[PATCH 0/6] t: add lint-style.pl and convert grep to test_grep

[PATCH 0/6] t: add lint-style.pl and convert grep to test_grep

[Michael Montalbo via GitGitGadget]

The test suite has a test_grep wrapper that prints file contents on
assertion failure, making debugging easier. Many tests still use bare 'grep'
for assertions, which silently swallows context on failure.

This series adds a lint tool (lint-style.pl) to mechanically detect and
convert these, then applies it across the test suite.

The tool reuses the shared shell parser (t/lib-shell-parser.pl) rather than
reimplementing shell parsing. This gives us proper handling of heredocs,
$(...), pipes, quoting, case patterns, and control flow structures for free.
The only new parsing logic is the grep assertion classifier, which works on
the already-parsed token stream.

The classifier distinguishes grep used as an assertion (checking exit status
against PATTERN + FILE) from grep used as a filter (pipes, redirects, $(),
control flow conditions). Only assertions are converted. Greps at assertion
level with no file argument are flagged as likely bugs; three pre-existing
instances were found and fixed in patch 5.

The --fix mode converts mechanically: 'grep' becomes 'test_grep', '! grep'
becomes 'test_grep !'.

Structure:

1/6 t/README: document test_grep helper 2/6 t: extract chainlint's parser
into shared module 3/6 t: fix Lexer line count for $() inside double-quoted
strings 4/6 t: add lint-style.pl with test_grep negation rule 5/6 t: fix
grep assertions missing file arguments 6/6 t: lint and convert grep
assertions to test_grep

Patch 2 extracts chainlint.pl's Lexer, ShellParser, and ScriptParser into
t/lib-shell-parser.pl. ScriptParser's check_test() becomes a no-op in the
module; chainlint.pl defines ChainlintParser (a ScriptParser subclass that
runs TestParser for &&-chain detection), and lint-style.pl defines
LintParser (a ScriptParser subclass that runs grep lint rules).

Patch 3 fixes a pre-existing bug in scan_dqstring where the post-loop
newline counter re-counted newlines that were already counted during
recursive $() parsing. The fix counts newlines inline as non-special
characters are consumed, removing the catch-all counter entirely. chainlint
is unaffected (it uses byte offsets), but lint-style.pl needs accurate token
line numbers to locate and fix specific lines in the original file.

Patch 4 introduces the lint-style.pl framework (LintParser subclass,
Makefile targets, fixture infrastructure) with a small, complete rule (!
test_grep -> test_grep !) so reviewers can see the machinery in action
before the bulk conversion.

Patch 5 fixes three test bugs where grep assertions were missing their file
arguments, causing them to pass vacuously (all three pass with the corrected
arguments). These were independently discovered by the missing-file
detection rule introduced in patch 6.

Patch 6 adds the main rule, its fixtures, and the mechanical conversion of
~2800 assertions across ~340 files, including sourced test fragments in
t/t5411/ and heredoc test bodies in t/t5564/.

To verify the conversion (patch 6 adds both the rule and the mechanical
conversion in the same commit, so apply the full series and re-run --fix to
confirm it produces no further changes):

git checkout && perl t/lint-style.pl --fix t/t*.sh t/test-lib*.sh t/lib-.sh
t/-tests.sh t/perf/.sh t/t5411/.sh

As an independent completeness check:

grep -rn '^\s*!\sgrep\s' t/t*.sh t/lib-.sh t/-tests.sh
t/test-lib*.sh t/perf/*.sh | grep -v test_grep | grep -v lint-ok | grep -v
'#.*grep'

Future rules:

The framework is designed to make adding new rules cheap. Each rule is a
function that receives parsed commands and the token stream. The harness
handles tokenization, line mapping, --fix, and fixture testing. Three
natural follow-ups:

 * 'test_must_fail grep': test_must_fail distinguishes expected failures
   from crashes (signals), which only makes sense for git commands. Using it
   with grep or test_grep should be '! grep' or 'test_grep !' instead.

 * '! git cmd': should use test_must_fail, which distinguishes controlled
   failures from crashes. The README explicitly documents this as a "don't".

 * 'test -f' / 'test -d' / 'test -e': should use test_path_is_file,
   test_path_is_dir, test_path_exists. The helpers print the actual
   directory listing on failure; bare 'test' just says "failed".

Known limitations:

 * One grep in t/t1400 asserts against .git/packed-refs which does not exist
   on the reftable backend; suppressed with '# lint-ok'.

 * One grep in t/t7450 checks a path inside a clone that may have failed
   (MINGW-only test); the file may not exist, so test_grep's existence check
   would trip; suppressed with '# lint-ok'.

 * Two greps in t/t3901 inside case branches that inherit piped stdin from
   two lines above are suppressed with '# lint-ok'.

 * One grep in t/t6437 uses glob expansion (grep -q content *) which breaks
   test_grep's file check; suppressed with '# lint-ok'.

 * One grep in t/t7527 captures $? for later use rather than asserting
   inline; suppressed with '# lint-ok'.

Michael Montalbo (6):
  t/README: document test_grep helper
  t: extract chainlint's parser into shared module
  t: fix Lexer line count for $() inside double-quoted strings
  t: add lint-style.pl with test_grep negation rule
  t: fix grep assertions missing file arguments
  t: lint and convert grep assertions to test_grep

 t/.gitattributes                             |   2 +
 t/Makefile                                   |  37 +-
 t/README                                     |  21 +
 t/chainlint.pl                               | 521 +-----------------
 t/check-shell-parser.pl                      |  58 +++
 t/for-each-ref-tests.sh                      |  12 +-
 t/lib-bitmap.sh                              |  12 +-
 t/lib-bundle-uri-protocol.sh                 |  26 +-
 t/lib-httpd.sh                               |   2 +-
 t/lib-shell-parser.pl                        | 522 +++++++++++++++++++
 t/lint-style.pl                              | 425 +++++++++++++++
 t/lint-style/grep-assert.expect              |  13 +
 t/lint-style/grep-assert.test                |  24 +
 t/lint-style/grep-fix.expect                 |  16 +
 t/lint-style/grep-fix.test                   |  16 +
 t/lint-style/grep-missing-file.expect        |   4 +
 t/lint-style/grep-missing-file.test          |   6 +
 t/lint-style/grep-negated.expect             |   5 +
 t/lint-style/grep-negated.test               |   9 +
 t/lint-style/grep-not-assert.expect          |   0
 t/lint-style/grep-not-assert.test            |  43 ++
 t/lint-style/heredoc.expect                  |   3 +
 t/lint-style/heredoc.test                    |  14 +
 t/lint-style/test-grep-negation-fix.expect   |   4 +
 t/lint-style/test-grep-negation-fix.test     |   4 +
 t/lint-style/test-grep-negation.expect       |   3 +
 t/lint-style/test-grep-negation.test         |   4 +
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 t/t9001-send-email.sh                        | 190 +++----
 t/t9003-help-autocorrect.sh                  |   6 +-
 t/t9106-git-svn-commit-diff-clobber.sh       |   2 +-
 t/t9107-git-svn-migrate.sh                   |  30 +-
 t/t9110-git-svn-use-svm-props.sh             |  20 +-
 t/t9111-git-svn-use-svnsync-props.sh         |  18 +-
 t/t9114-git-svn-dcommit-merge.sh             |   6 +-
 t/t9116-git-svn-log.sh                       |   8 +-
 t/t9117-git-svn-init-clone.sh                |  12 +-
 t/t9119-git-svn-info.sh                      |  16 +-
 t/t9122-git-svn-author.sh                    |   8 +-
 t/t9130-git-svn-authors-file.sh              |   8 +-
 t/t9138-git-svn-authors-prog.sh              |  14 +-
 t/t9140-git-svn-reset.sh                     |   4 +-
 t/t9153-git-svn-rewrite-uuid.sh              |   4 +-
 t/t9200-git-cvsexportcommit.sh               |   2 +-
 t/t9210-scalar.sh                            |  34 +-
 t/t9211-scalar-clone.sh                      |  16 +-
 t/t9300-fast-import.sh                       |  10 +-
 t/t9350-fast-export.sh                       |  54 +-
 t/t9351-fast-export-anonymize.sh             |  36 +-
 t/t9400-git-cvsserver-server.sh              |   4 +-
 t/t9501-gitweb-standalone-http-status.sh     |  58 +--
 t/t9502-gitweb-standalone-parse-output.sh    |  38 +-
 t/t9800-git-p4-basic.sh                      |  10 +-
 t/t9801-git-p4-branch.sh                     |  48 +-
 t/t9806-git-p4-options.sh                    |  10 +-
 t/t9807-git-p4-submit.sh                     |   2 +-
 t/t9810-git-p4-rcs.sh                        |   8 +-
 t/t9813-git-p4-preserve-users.sh             |   8 +-
 t/t9814-git-p4-rename.sh                     |   8 +-
 t/t9827-git-p4-change-filetype.sh            |   4 +-
 t/t9832-unshelve.sh                          |   6 +-
 t/t9833-errors.sh                            |   4 +-
 t/t9835-git-p4-metadata-encoding-python2.sh  |  36 +-
 t/t9836-git-p4-metadata-encoding-python3.sh  |  38 +-
 t/t9850-shell.sh                             |   2 +-
 t/t9902-completion.sh                        |  26 +-
 363 files changed, 4067 insertions(+), 3334 deletions(-)
 create mode 100644 t/check-shell-parser.pl
 create mode 100644 t/lib-shell-parser.pl
 create mode 100755 t/lint-style.pl
 create mode 100644 t/lint-style/grep-assert.expect
 create mode 100644 t/lint-style/grep-assert.test
 create mode 100644 t/lint-style/grep-fix.expect
 create mode 100644 t/lint-style/grep-fix.test
 create mode 100644 t/lint-style/grep-missing-file.expect
 create mode 100644 t/lint-style/grep-missing-file.test
 create mode 100644 t/lint-style/grep-negated.expect
 create mode 100644 t/lint-style/grep-negated.test
 create mode 100644 t/lint-style/grep-not-assert.expect
 create mode 100644 t/lint-style/grep-not-assert.test
 create mode 100644 t/lint-style/heredoc.expect
 create mode 100644 t/lint-style/heredoc.test
 create mode 100644 t/lint-style/test-grep-negation-fix.expect
 create mode 100644 t/lint-style/test-grep-negation-fix.test
 create mode 100644 t/lint-style/test-grep-negation.expect
 create mode 100644 t/lint-style/test-grep-negation.test


base-commit: 9ac3f193c05c2237e2b14ebaa1149e9fc8a1abe0
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2135%2Fmmontalbo%2Fmm%2Ftest-grep-docs-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2135/mmontalbo/mm/test-grep-docs-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/2135
-- 
gitgitgadget

[PATCH 1/6] t/README: document test_grep helper

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

test_grep is a wrapper around grep for test assertions that prints
the file contents on failure for easier debugging.  It also accepts
'!' as its first argument for negation, which preserves the
diagnostic output that '! test_grep' would suppress.

Despite being widely used (and the preferred replacement for bare
grep in assertions), test_grep has no entry in t/README alongside
the other documented helpers like test_cmp and test_line_count.
Add one.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 t/README | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/t/README b/t/README
index adbbd9acf4..c12a1c317a 100644
--- a/t/README
+++ b/t/README
@@ -1039,6 +1039,27 @@ see test-lib-functions.sh for the full list and their options.
 
    Check whether a file has the length it is expected to.
 
+ - test_grep [!] [<grep-options>] <pattern> <file>
+
+   Check whether <file> contains a line matching <pattern>, or
+   with '!' that no line matches.  Use this instead of bare
+   'grep <pattern> <file>' in test assertions.  On failure,
+   test_grep prints the contents of <file> for easier debugging,
+   whereas a bare 'grep' would fail silently.
+
+   For negation, pass '!' as the first argument:
+
+	test_grep ! "^diff --git" actual
+
+   Do not negate by writing '! test_grep', as that suppresses the
+   diagnostic output.
+
+   test_grep should only be used as a test assertion.  When grep
+   is used as a data filter (e.g. 'grep -v "^index" actual >filtered')
+   or inside a command substitution (e.g. '$(grep -c ...)'), plain
+   'grep' is the right choice because the exit code is not the
+   assertion itself.
+
  - test_path_is_file <path>
    test_path_is_dir <path>
    test_path_is_missing <path>
-- 
gitgitgadget

[PATCH 2/6] t: extract chainlint's parser into shared module

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

Move the Lexer, ShellParser, and ScriptParser packages from
chainlint.pl into t/lib-shell-parser.pl so they can be reused by
other tools.  ScriptParser's check_test() is a no-op in the shared
module; callers subclass ScriptParser and override it.

chainlint.pl defines TestParser (&&-chain detection) and
ChainlintParser (a ScriptParser subclass whose check_test runs
TestParser and formats the results).  The shared module is loaded
via do() for portability with minimal Perl installations.

A subsequent commit introduces lint-style.pl which needs the same
shell parser to properly tokenize test scripts.  Sharing the parser
avoids reimplementing heredoc handling, $(...) nesting, pipe
tracking, quoting, and test body extraction.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 t/chainlint.pl        | 521 ++----------------------------------------
 t/lib-shell-parser.pl | 517 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 530 insertions(+), 508 deletions(-)
 create mode 100644 t/lib-shell-parser.pl

diff --git a/t/chainlint.pl b/t/chainlint.pl
index f0598e3934..49b7cc6cb8 100755
--- a/t/chainlint.pl
+++ b/t/chainlint.pl
@@ -23,458 +23,10 @@ my $jobs = -1;
 my $show_stats;
 my $emit_all;
 
-# Lexer tokenizes POSIX shell scripts. It is roughly modeled after section 2.3
-# "Token Recognition" of POSIX chapter 2 "Shell Command Language". Although
-# similar to lexical analyzers for other languages, this one differs in a few
-# substantial ways due to quirks of the shell command language.
-#
-# For instance, in many languages, newline is just whitespace like space or
-# TAB, but in shell a newline is a command separator, thus a distinct lexical
-# token. A newline is significant and returned as a distinct token even at the
-# end of a shell comment.
-#
-# In other languages, `1+2` would typically be scanned as three tokens
-# (`1`, `+`, and `2`), but in shell it is a single token. However, the similar
-# `1 + 2`, which embeds whitepace, is scanned as three token in shell, as well.
-# In shell, several characters with special meaning lose that meaning when not
-# surrounded by whitespace. For instance, the negation operator `!` is special
-# when standing alone surrounded by whitespace; whereas in `foo!uucp` it is
-# just a plain character in the longer token "foo!uucp". In many other
-# languages, `"string"/foo:'string'` might be scanned as five tokens ("string",
-# `/`, `foo`, `:`, and 'string'), but in shell, it is just a single token.
-#
-# The lexical analyzer for the shell command language is also somewhat unusual
-# in that it recursively invokes the parser to handle the body of `$(...)`
-# expressions which can contain arbitrary shell code. Such expressions may be
-# encountered both inside and outside of double-quoted strings.
-#
-# The lexical analyzer is responsible for consuming shell here-doc bodies which
-# extend from the line following a `<<TAG` operator until a line consisting
-# solely of `TAG`. Here-doc consumption begins when a newline is encountered.
-# It is legal for multiple here-doc `<<TAG` operators to be present on a single
-# line, in which case their bodies must be present one following the next, and
-# are consumed in the (left-to-right) order the `<<TAG` operators appear on the
-# line. A special complication is that the bodies of all here-docs must be
-# consumed when the newline is encountered even if the parse context depth has
-# changed. For instance, in `cat <<A && x=$(cat <<B &&\n`, bodies of here-docs
-# "A" and "B" must be consumed even though "A" was introduced outside the
-# recursive parse context in which "B" was introduced and in which the newline
-# is encountered.
-package Lexer;
-
-sub new {
-	my ($class, $parser, $s) = @_;
-	bless {
-		parser => $parser,
-		buff => $s,
-		lineno => 1,
-		heretags => []
-	} => $class;
-}
-
-sub scan_heredoc_tag {
-	my $self = shift @_;
-	${$self->{buff}} =~ /\G(-?)/gc;
-	my $indented = $1;
-	my $token = $self->scan_token();
-	return "<<$indented" unless $token;
-	my $tag = $token->[0];
-	$tag =~ s/['"\\]//g;
-	$$token[0] = $indented ? "\t$tag" : "$tag";
-	push(@{$self->{heretags}}, $token);
-	return "<<$indented$tag";
-}
-
-sub scan_op {
-	my ($self, $c) = @_;
-	my $b = $self->{buff};
-	return $c unless $$b =~ /\G(.)/sgc;
-	my $cc = $c . $1;
-	return scan_heredoc_tag($self) if $cc eq '<<';
-	return $cc if $cc =~ /^(?:&&|\|\||>>|;;|<&|>&|<>|>\|)$/;
-	pos($$b)--;
-	return $c;
-}
-
-sub scan_sqstring {
-	my $self = shift @_;
-	${$self->{buff}} =~ /\G([^']*'|.*\z)/sgc;
-	my $s = $1;
-	$self->{lineno} += () = $s =~ /\n/sg;
-	return "'" . $s;
-}
-
-sub scan_dqstring {
-	my $self = shift @_;
-	my $b = $self->{buff};
-	my $s = '"';
-	while (1) {
-		# slurp up non-special characters
-		$s .= $1 if $$b =~ /\G([^"\$\\]+)/gc;
-		# handle special characters
-		last unless $$b =~ /\G(.)/sgc;
-		my $c = $1;
-		$s .= '"', last if $c eq '"';
-		$s .= '$' . $self->scan_dollar(), next if $c eq '$';
-		if ($c eq '\\') {
-			$s .= '\\', last unless $$b =~ /\G(.)/sgc;
-			$c = $1;
-			$self->{lineno}++, next if $c eq "\n"; # line splice
-			# backslash escapes only $, `, ", \ in dq-string
-			$s .= '\\' unless $c =~ /^[\$`"\\]$/;
-			$s .= $c;
-			next;
-		}
-		die("internal error scanning dq-string '$c'\n");
-	}
-	$self->{lineno} += () = $s =~ /\n/sg;
-	return $s;
-}
-
-sub scan_balanced {
-	my ($self, $c1, $c2) = @_;
-	my $b = $self->{buff};
-	my $depth = 1;
-	my $s = $c1;
-	while ($$b =~ /\G([^\Q$c1$c2\E]*(?:[\Q$c1$c2\E]|\z))/gc) {
-		$s .= $1;
-		$depth++, next if $s =~ /\Q$c1\E$/;
-		$depth--;
-		last if $depth == 0;
-	}
-	$self->{lineno} += () = $s =~ /\n/sg;
-	return $s;
-}
-
-sub scan_subst {
-	my $self = shift @_;
-	my @tokens = $self->{parser}->parse(qr/^\)$/);
-	$self->{parser}->next_token(); # closing ")"
-	return @tokens;
-}
-
-sub scan_dollar {
-	my $self = shift @_;
-	my $b = $self->{buff};
-	return $self->scan_balanced('(', ')') if $$b =~ /\G\((?=\()/gc; # $((...))
-	return '(' . join(' ', map {$_->[0]} $self->scan_subst()) . ')' if $$b =~ /\G\(/gc; # $(...)
-	return $self->scan_balanced('{', '}') if $$b =~ /\G\{/gc; # ${...}
-	return $1 if $$b =~ /\G(\w+)/gc; # $var
-	return $1 if $$b =~ /\G([@*#?$!0-9-])/gc; # $*, $1, $$, etc.
-	return '';
-}
-
-sub swallow_heredocs {
-	my $self = shift @_;
-	my $b = $self->{buff};
-	my $tags = $self->{heretags};
-	while (my $tag = shift @$tags) {
-		my $start = pos($$b);
-		my $indent = $$tag[0] =~ s/^\t// ? '\\s*' : '';
-		$$b =~ /(?:\G|\n)$indent\Q$$tag[0]\E(?:\n|\z)/gc;
-		if (pos($$b) > $start) {
-			my $body = substr($$b, $start, pos($$b) - $start);
-			$self->{parser}->{heredocs}->{$$tag[0]} = {
-				content => substr($body, 0, length($body) - length($&)),
-				start_line => $self->{lineno},
-		        };
-			$self->{lineno} += () = $body =~ /\n/sg;
-			next;
-		}
-		push(@{$self->{parser}->{problems}}, ['HEREDOC', $tag]);
-		$$b =~ /(?:\G|\n).*\z/gc; # consume rest of input
-		my $body = substr($$b, $start, pos($$b) - $start);
-		$self->{lineno} += () = $body =~ /\n/sg;
-		last;
-	}
-}
-
-sub scan_token {
-	my $self = shift @_;
-	my $b = $self->{buff};
-	my $token = '';
-	my ($start, $startln);
-RESTART:
-	$startln = $self->{lineno};
-	$$b =~ /\G[ \t]+/gc; # skip whitespace (but not newline)
-	$start = pos($$b) || 0;
-	$self->{lineno}++, return ["\n", $start, pos($$b), $startln, $startln] if $$b =~ /\G#[^\n]*(?:\n|\z)/gc; # comment
-	while (1) {
-		# slurp up non-special characters
-		$token .= $1 if $$b =~ /\G([^\\;&|<>(){}'"\$\s]+)/gc;
-		# handle special characters
-		last unless $$b =~ /\G(.)/sgc;
-		my $c = $1;
-		pos($$b)--, last if $c =~ /^[ \t]$/; # whitespace ends token
-		pos($$b)--, last if length($token) && $c =~ /^[;&|<>(){}\n]$/;
-		$token .= $self->scan_sqstring(), next if $c eq "'";
-		$token .= $self->scan_dqstring(), next if $c eq '"';
-		$token .= $c . $self->scan_dollar(), next if $c eq '$';
-		$self->{lineno}++, $self->swallow_heredocs(), $token = $c, last if $c eq "\n";
-		$token = $self->scan_op($c), last if $c =~ /^[;&|<>]$/;
-		$token = $c, last if $c =~ /^[(){}]$/;
-		if ($c eq '\\') {
-			$token .= '\\', last unless $$b =~ /\G(.)/sgc;
-			$c = $1;
-			$self->{lineno}++, next if $c eq "\n" && length($token); # line splice
-			$self->{lineno}++, goto RESTART if $c eq "\n"; # line splice
-			$token .= '\\' . $c;
-			next;
-		}
-		die("internal error scanning character '$c'\n");
-	}
-	return length($token) ? [$token, $start, pos($$b), $startln, $self->{lineno}] : undef;
-}
-
-# ShellParser parses POSIX shell scripts (with minor extensions for Bash). It
-# is a recursive descent parser very roughly modeled after section 2.10 "Shell
-# Grammar" of POSIX chapter 2 "Shell Command Language".
-package ShellParser;
-
-sub new {
-	my ($class, $s) = @_;
-	my $self = bless {
-		buff => [],
-		stop => [],
-		output => [],
-		heredocs => {},
-		insubshell => 0,
-	} => $class;
-	$self->{lexer} = Lexer->new($self, $s);
-	return $self;
-}
-
-sub next_token {
-	my $self = shift @_;
-	return pop(@{$self->{buff}}) if @{$self->{buff}};
-	return $self->{lexer}->scan_token();
-}
-
-sub untoken {
-	my $self = shift @_;
-	push(@{$self->{buff}}, @_);
-}
-
-sub peek {
-	my $self = shift @_;
-	my $token = $self->next_token();
-	return undef unless defined($token);
-	$self->untoken($token);
-	return $token;
-}
-
-sub stop_at {
-	my ($self, $token) = @_;
-	return 1 unless defined($token);
-	my $stop = ${$self->{stop}}[-1] if @{$self->{stop}};
-	return defined($stop) && $token->[0] =~ $stop;
-}
-
-sub expect {
-	my ($self, $expect) = @_;
-	my $token = $self->next_token();
-	return $token if defined($token) && $token->[0] eq $expect;
-	push(@{$self->{output}}, "?!ERR?! expected '$expect' but found '" . (defined($token) ? $token->[0] : "<end-of-input>") . "'\n");
-	$self->untoken($token) if defined($token);
-	return ();
-}
-
-sub optional_newlines {
-	my $self = shift @_;
-	my @tokens;
-	while (my $token = $self->peek()) {
-		last unless $token->[0] eq "\n";
-		push(@tokens, $self->next_token());
-	}
-	return @tokens;
-}
-
-sub parse_group {
-	my $self = shift @_;
-	return ($self->parse(qr/^}$/),
-		$self->expect('}'));
-}
-
-sub parse_subshell {
-	my $self = shift @_;
-	$self->{insubshell}++;
-	my @tokens = ($self->parse(qr/^\)$/),
-		      $self->expect(')'));
-	$self->{insubshell}--;
-	return @tokens;
-}
-
-sub parse_case_pattern {
-	my $self = shift @_;
-	my @tokens;
-	while (defined(my $token = $self->next_token())) {
-		push(@tokens, $token);
-		last if $token->[0] eq ')';
-	}
-	return @tokens;
-}
-
-sub parse_case {
-	my $self = shift @_;
-	my @tokens;
-	push(@tokens,
-	     $self->next_token(), # subject
-	     $self->optional_newlines(),
-	     $self->expect('in'),
-	     $self->optional_newlines());
-	while (1) {
-		my $token = $self->peek();
-		last unless defined($token) && $token->[0] ne 'esac';
-		push(@tokens,
-		     $self->parse_case_pattern(),
-		     $self->optional_newlines(),
-		     $self->parse(qr/^(?:;;|esac)$/)); # item body
-		$token = $self->peek();
-		last unless defined($token) && $token->[0] ne 'esac';
-		push(@tokens,
-		     $self->expect(';;'),
-		     $self->optional_newlines());
-	}
-	push(@tokens, $self->expect('esac'));
-	return @tokens;
-}
-
-sub parse_for {
-	my $self = shift @_;
-	my @tokens;
-	push(@tokens,
-	     $self->next_token(), # variable
-	     $self->optional_newlines());
-	my $token = $self->peek();
-	if (defined($token) && $token->[0] eq 'in') {
-		push(@tokens,
-		     $self->expect('in'),
-		     $self->optional_newlines());
-	}
-	push(@tokens,
-	     $self->parse(qr/^do$/), # items
-	     $self->expect('do'),
-	     $self->optional_newlines(),
-	     $self->parse_loop_body(),
-	     $self->expect('done'));
-	return @tokens;
-}
-
-sub parse_if {
-	my $self = shift @_;
-	my @tokens;
-	while (1) {
-		push(@tokens,
-		     $self->parse(qr/^then$/), # if/elif condition
-		     $self->expect('then'),
-		     $self->optional_newlines(),
-		     $self->parse(qr/^(?:elif|else|fi)$/)); # if/elif body
-		my $token = $self->peek();
-		last unless defined($token) && $token->[0] eq 'elif';
-		push(@tokens, $self->expect('elif'));
-	}
-	my $token = $self->peek();
-	if (defined($token) && $token->[0] eq 'else') {
-		push(@tokens,
-		     $self->expect('else'),
-		     $self->optional_newlines(),
-		     $self->parse(qr/^fi$/)); # else body
-	}
-	push(@tokens, $self->expect('fi'));
-	return @tokens;
-}
-
-sub parse_loop_body {
-	my $self = shift @_;
-	return $self->parse(qr/^done$/);
-}
-
-sub parse_loop {
-	my $self = shift @_;
-	return ($self->parse(qr/^do$/), # condition
-		$self->expect('do'),
-		$self->optional_newlines(),
-		$self->parse_loop_body(),
-		$self->expect('done'));
-}
-
-sub parse_func {
-	my $self = shift @_;
-	return ($self->expect('('),
-		$self->expect(')'),
-		$self->optional_newlines(),
-		$self->parse_cmd()); # body
-}
-
-sub parse_bash_array_assignment {
-	my $self = shift @_;
-	my @tokens = $self->expect('(');
-	while (defined(my $token = $self->next_token())) {
-		push(@tokens, $token);
-		last if $token->[0] eq ')';
-	}
-	return @tokens;
-}
-
-my %compound = (
-	'{' => \&parse_group,
-	'(' => \&parse_subshell,
-	'case' => \&parse_case,
-	'for' => \&parse_for,
-	'if' => \&parse_if,
-	'until' => \&parse_loop,
-	'while' => \&parse_loop);
-
-sub parse_cmd {
-	my $self = shift @_;
-	my $cmd = $self->next_token();
-	return () unless defined($cmd);
-	return $cmd if $cmd->[0] eq "\n";
-
-	my $token;
-	my @tokens = $cmd;
-	if ($cmd->[0] eq '!') {
-		push(@tokens, $self->parse_cmd());
-		return @tokens;
-	} elsif (my $f = $compound{$cmd->[0]}) {
-		push(@tokens, $self->$f());
-	} elsif (defined($token = $self->peek()) && $token->[0] eq '(') {
-		if ($cmd->[0] !~ /\w=$/) {
-			push(@tokens, $self->parse_func());
-			return @tokens;
-		}
-		my @array = $self->parse_bash_array_assignment();
-		$tokens[-1]->[0] .= join(' ', map {$_->[0]} @array);
-		$tokens[-1]->[2] = $array[$#array][2] if @array;
-	}
-
-	while (defined(my $token = $self->next_token())) {
-		$self->untoken($token), last if $self->stop_at($token);
-		push(@tokens, $token);
-		last if $token->[0] =~ /^(?:[;&\n|]|&&|\|\|)$/;
-	}
-	push(@tokens, $self->next_token()) if $tokens[-1]->[0] ne "\n" && defined($token = $self->peek()) && $token->[0] eq "\n";
-	return @tokens;
-}
-
-sub accumulate {
-	my ($self, $tokens, $cmd) = @_;
-	push(@$tokens, @$cmd);
-}
-
-sub parse {
-	my ($self, $stop) = @_;
-	push(@{$self->{stop}}, $stop);
-	goto DONE if $self->stop_at($self->peek());
-	my @tokens;
-	while (my @cmd = $self->parse_cmd()) {
-		$self->accumulate(\@tokens, \@cmd);
-		last if $self->stop_at($self->peek());
-	}
-DONE:
-	pop(@{$self->{stop}});
-	return @tokens;
-}
+use File::Basename;
+my $_lib = dirname($0) . "/lib-shell-parser.pl";
+$_lib = "./$_lib" unless $_lib =~ m{^/};
+do $_lib or die "failed to load $_lib: $@$!\n";
 
 # TestParser is a subclass of ShellParser which, beyond parsing shell script
 # code, is also imbued with semantic knowledge of test construction, and checks
@@ -484,7 +36,7 @@ DONE:
 # scripts in which the tests are defined.
 package TestParser;
 
-use base 'ShellParser';
+our @ISA = ('ShellParser');
 
 sub new {
 	my $class = shift @_;
@@ -578,14 +130,12 @@ DONE:
 	$self->SUPER::accumulate($tokens, $cmd);
 }
 
-# ScriptParser is a subclass of ShellParser which identifies individual test
-# definitions within test scripts, and passes each test body through TestParser
-# to identify possible problems. ShellParser detects test definitions not only
-# at the top-level of test scripts but also within compound commands such as
-# loops and function definitions.
-package ScriptParser;
+# ChainlintParser is a subclass of ScriptParser which checks each test
+# body for broken &&-chains via TestParser, then formats and collects
+# the results.
+package ChainlintParser;
 
-use base 'ShellParser';
+our @ISA = ('ScriptParser');
 
 sub new {
 	my $class = shift @_;
@@ -595,35 +145,6 @@ sub new {
 	return $self;
 }
 
-# extract the raw content of a token, which may be a single string or a
-# composition of multiple strings and non-string character runs; for instance,
-# `"test body"` unwraps to `test body`; `word"a b"42'c d'` to `worda b42c d`
-sub unwrap {
-	my $token = (@_ ? shift @_ : $_)->[0];
-	# simple case: 'sqstring' or "dqstring"
-	return $token if $token =~ s/^'([^']*)'$/$1/;
-	return $token if $token =~ s/^"([^"]*)"$/$1/;
-
-	# composite case
-	my ($s, $q, $escaped);
-	while (1) {
-		# slurp up non-special characters
-		$s .= $1 if $token =~ /\G([^\\'"]*)/gc;
-		# handle special characters
-		last unless $token =~ /\G(.)/sgc;
-		my $c = $1;
-		$q = undef, next if defined($q) && $c eq $q;
-		$q = $c, next if !defined($q) && $c =~ /^['"]$/;
-		if ($c eq '\\') {
-			last unless $token =~ /\G(.)/sgc;
-			$c = $1;
-			$s .= '\\' if $c eq "\n"; # preserve line splice
-		}
-		$s .= $c;
-	}
-	return $s
-}
-
 sub format_problem {
 	local $_ = shift;
 	/^AMP$/ && return "missing '&&'";
@@ -635,10 +156,10 @@ sub format_problem {
 
 sub check_test {
 	my $self = shift @_;
-	my $title = unwrap(shift @_);
+	my $title = ScriptParser::unwrap(shift @_);
 	my $body = shift @_;
 	my $lineno = $body->[3];
-	$body = unwrap($body);
+	$body = ScriptParser::unwrap($body);
 	if ($body eq '-') {
 		my $herebody = shift @_;
 		$body = $herebody->{content};
@@ -673,22 +194,6 @@ sub check_test {
 	push(@{$self->{output}}, "$c->{blue}# chainlint: $title$c->{reset}\n$checked");
 }
 
-sub parse_cmd {
-	my $self = shift @_;
-	my @tokens = $self->SUPER::parse_cmd();
-	return @tokens unless @tokens && $tokens[0]->[0] =~ /^test_expect_(?:success|failure)$/;
-	my $n = $#tokens;
-	$n-- while $n >= 0 && $tokens[$n]->[0] =~ /^(?:[;&\n|]|&&|\|\|)$/;
-	my $herebody;
-	if ($n >= 2 && $tokens[$n-1]->[0] eq '-' && $tokens[$n]->[0] =~ /^<<-?(.+)$/) {
-		$herebody = $self->{heredocs}->{$1};
-		$n--;
-	}
-	$self->check_test($tokens[1], $tokens[2], $herebody) if $n == 2; # title body
-	$self->check_test($tokens[2], $tokens[3], $herebody) if $n > 2;  # prereq title body
-	return @tokens;
-}
-
 # main contains high-level functionality for processing command-line switches,
 # feeding input test scripts to ScriptParser, and reporting results.
 package main;
@@ -803,7 +308,7 @@ sub check_script {
 		}
 		my $s = do { local $/; <$fh> };
 		close($fh);
-		my $parser = ScriptParser->new(\$s);
+		my $parser = ChainlintParser->new(\$s);
 		1 while $parser->parse_cmd();
 		if (@{$parser->{output}}) {
 			my $c = fd_colors(1);
diff --git a/t/lib-shell-parser.pl b/t/lib-shell-parser.pl
new file mode 100644
index 0000000000..1e521a94f8
--- /dev/null
+++ b/t/lib-shell-parser.pl
@@ -0,0 +1,517 @@
+use strict;
+use warnings;
+
+# Copyright (c) 2021-2022 Eric Sunshine <sunshine@sunshineco.com>
+#
+# Lexer tokenizes POSIX shell scripts. It is roughly modeled after section 2.3
+# "Token Recognition" of POSIX chapter 2 "Shell Command Language". Although
+# similar to lexical analyzers for other languages, this one differs in a few
+# substantial ways due to quirks of the shell command language.
+#
+# For instance, in many languages, newline is just whitespace like space or
+# TAB, but in shell a newline is a command separator, thus a distinct lexical
+# token. A newline is significant and returned as a distinct token even at the
+# end of a shell comment.
+#
+# In other languages, `1+2` would typically be scanned as three tokens
+# (`1`, `+`, and `2`), but in shell it is a single token. However, the similar
+# `1 + 2`, which embeds whitepace, is scanned as three token in shell, as well.
+# In shell, several characters with special meaning lose that meaning when not
+# surrounded by whitespace. For instance, the negation operator `!` is special
+# when standing alone surrounded by whitespace; whereas in `foo!uucp` it is
+# just a plain character in the longer token "foo!uucp". In many other
+# languages, `"string"/foo:'string'` might be scanned as five tokens ("string",
+# `/`, `foo`, `:`, and 'string'), but in shell, it is just a single token.
+#
+# The lexical analyzer for the shell command language is also somewhat unusual
+# in that it recursively invokes the parser to handle the body of `$(...)`
+# expressions which can contain arbitrary shell code. Such expressions may be
+# encountered both inside and outside of double-quoted strings.
+#
+# The lexical analyzer is responsible for consuming shell here-doc bodies which
+# extend from the line following a `<<TAG` operator until a line consisting
+# solely of `TAG`. Here-doc consumption begins when a newline is encountered.
+# It is legal for multiple here-doc `<<TAG` operators to be present on a single
+# line, in which case their bodies must be present one following the next, and
+# are consumed in the (left-to-right) order the `<<TAG` operators appear on the
+# line. A special complication is that the bodies of all here-docs must be
+# consumed when the newline is encountered even if the parse context depth has
+# changed. For instance, in `cat <<A && x=$(cat <<B &&\n`, bodies of here-docs
+# "A" and "B" must be consumed even though "A" was introduced outside the
+# recursive parse context in which "B" was introduced and in which the newline
+# is encountered.
+package Lexer;
+
+sub new {
+	my ($class, $parser, $s) = @_;
+	bless {
+		parser => $parser,
+		buff => $s,
+		lineno => 1,
+		heretags => []
+	} => $class;
+}
+
+sub scan_heredoc_tag {
+	my $self = shift @_;
+	${$self->{buff}} =~ /\G(-?)/gc;
+	my $indented = $1;
+	my $token = $self->scan_token();
+	return "<<$indented" unless $token;
+	my $tag = $token->[0];
+	$tag =~ s/['"\\]//g;
+	$$token[0] = $indented ? "\t$tag" : "$tag";
+	push(@{$self->{heretags}}, $token);
+	return "<<$indented$tag";
+}
+
+sub scan_op {
+	my ($self, $c) = @_;
+	my $b = $self->{buff};
+	return $c unless $$b =~ /\G(.)/sgc;
+	my $cc = $c . $1;
+	return scan_heredoc_tag($self) if $cc eq '<<';
+	return $cc if $cc =~ /^(?:&&|\|\||>>|;;|<&|>&|<>|>\|)$/;
+	pos($$b)--;
+	return $c;
+}
+
+sub scan_sqstring {
+	my $self = shift @_;
+	${$self->{buff}} =~ /\G([^']*'|.*\z)/sgc;
+	my $s = $1;
+	$self->{lineno} += () = $s =~ /\n/sg;
+	return "'" . $s;
+}
+
+sub scan_dqstring {
+	my $self = shift @_;
+	my $b = $self->{buff};
+	my $s = '"';
+	while (1) {
+		# slurp up non-special characters
+		$s .= $1 if $$b =~ /\G([^"\$\\]+)/gc;
+		# handle special characters
+		last unless $$b =~ /\G(.)/sgc;
+		my $c = $1;
+		$s .= '"', last if $c eq '"';
+		$s .= '$' . $self->scan_dollar(), next if $c eq '$';
+		if ($c eq '\\') {
+			$s .= '\\', last unless $$b =~ /\G(.)/sgc;
+			$c = $1;
+			$self->{lineno}++, next if $c eq "\n"; # line splice
+			# backslash escapes only $, `, ", \ in dq-string
+			$s .= '\\' unless $c =~ /^[\$`"\\]$/;
+			$s .= $c;
+			next;
+		}
+		die("internal error scanning dq-string '$c'\n");
+	}
+	$self->{lineno} += () = $s =~ /\n/sg;
+	return $s;
+}
+
+sub scan_balanced {
+	my ($self, $c1, $c2) = @_;
+	my $b = $self->{buff};
+	my $depth = 1;
+	my $s = $c1;
+	while ($$b =~ /\G([^\Q$c1$c2\E]*(?:[\Q$c1$c2\E]|\z))/gc) {
+		$s .= $1;
+		$depth++, next if $s =~ /\Q$c1\E$/;
+		$depth--;
+		last if $depth == 0;
+	}
+	$self->{lineno} += () = $s =~ /\n/sg;
+	return $s;
+}
+
+sub scan_subst {
+	my $self = shift @_;
+	my @tokens = $self->{parser}->parse(qr/^\)$/);
+	$self->{parser}->next_token(); # closing ")"
+	return @tokens;
+}
+
+sub scan_dollar {
+	my $self = shift @_;
+	my $b = $self->{buff};
+	return $self->scan_balanced('(', ')') if $$b =~ /\G\((?=\()/gc; # $((...))
+	return '(' . join(' ', map {$_->[0]} $self->scan_subst()) . ')' if $$b =~ /\G\(/gc; # $(...)
+	return $self->scan_balanced('{', '}') if $$b =~ /\G\{/gc; # ${...}
+	return $1 if $$b =~ /\G(\w+)/gc; # $var
+	return $1 if $$b =~ /\G([@*#?$!0-9-])/gc; # $*, $1, $$, etc.
+	return '';
+}
+
+sub swallow_heredocs {
+	my $self = shift @_;
+	my $b = $self->{buff};
+	my $tags = $self->{heretags};
+	while (my $tag = shift @$tags) {
+		my $start = pos($$b);
+		my $indent = $$tag[0] =~ s/^\t// ? '\\s*' : '';
+		$$b =~ /(?:\G|\n)$indent\Q$$tag[0]\E(?:\n|\z)/gc;
+		if (pos($$b) > $start) {
+			my $body = substr($$b, $start, pos($$b) - $start);
+			$self->{parser}->{heredocs}->{$$tag[0]} = {
+				content => substr($body, 0, length($body) - length($&)),
+				start_line => $self->{lineno},
+		        };
+			$self->{lineno} += () = $body =~ /\n/sg;
+			next;
+		}
+		push(@{$self->{parser}->{problems}}, ['HEREDOC', $tag]);
+		$$b =~ /(?:\G|\n).*\z/gc; # consume rest of input
+		my $body = substr($$b, $start, pos($$b) - $start);
+		$self->{lineno} += () = $body =~ /\n/sg;
+		last;
+	}
+}
+
+sub scan_token {
+	my $self = shift @_;
+	my $b = $self->{buff};
+	my $token = '';
+	my ($start, $startln);
+RESTART:
+	$startln = $self->{lineno};
+	$$b =~ /\G[ \t]+/gc; # skip whitespace (but not newline)
+	$start = pos($$b) || 0;
+	$self->{lineno}++, return ["\n", $start, pos($$b), $startln, $startln] if $$b =~ /\G#[^\n]*(?:\n|\z)/gc; # comment
+	while (1) {
+		# slurp up non-special characters
+		$token .= $1 if $$b =~ /\G([^\\;&|<>(){}'"\$\s]+)/gc;
+		# handle special characters
+		last unless $$b =~ /\G(.)/sgc;
+		my $c = $1;
+		pos($$b)--, last if $c =~ /^[ \t]$/; # whitespace ends token
+		pos($$b)--, last if length($token) && $c =~ /^[;&|<>(){}\n]$/;
+		$token .= $self->scan_sqstring(), next if $c eq "'";
+		$token .= $self->scan_dqstring(), next if $c eq '"';
+		$token .= $c . $self->scan_dollar(), next if $c eq '$';
+		$self->{lineno}++, $self->swallow_heredocs(), $token = $c, last if $c eq "\n";
+		$token = $self->scan_op($c), last if $c =~ /^[;&|<>]$/;
+		$token = $c, last if $c =~ /^[(){}]$/;
+		if ($c eq '\\') {
+			$token .= '\\', last unless $$b =~ /\G(.)/sgc;
+			$c = $1;
+			$self->{lineno}++, next if $c eq "\n" && length($token); # line splice
+			$self->{lineno}++, goto RESTART if $c eq "\n"; # line splice
+			$token .= '\\' . $c;
+			next;
+		}
+		die("internal error scanning character '$c'\n");
+	}
+	return length($token) ? [$token, $start, pos($$b), $startln, $self->{lineno}] : undef;
+}
+
+# ShellParser parses POSIX shell scripts (with minor extensions for Bash). It
+# is a recursive descent parser very roughly modeled after section 2.10 "Shell
+# Grammar" of POSIX chapter 2 "Shell Command Language".
+package ShellParser;
+
+sub new {
+	my ($class, $s) = @_;
+	my $self = bless {
+		buff => [],
+		stop => [],
+		output => [],
+		heredocs => {},
+		insubshell => 0,
+	} => $class;
+	$self->{lexer} = Lexer->new($self, $s);
+	return $self;
+}
+
+sub next_token {
+	my $self = shift @_;
+	return pop(@{$self->{buff}}) if @{$self->{buff}};
+	return $self->{lexer}->scan_token();
+}
+
+sub untoken {
+	my $self = shift @_;
+	push(@{$self->{buff}}, @_);
+}
+
+sub peek {
+	my $self = shift @_;
+	my $token = $self->next_token();
+	return undef unless defined($token);
+	$self->untoken($token);
+	return $token;
+}
+
+sub stop_at {
+	my ($self, $token) = @_;
+	return 1 unless defined($token);
+	my $stop = ${$self->{stop}}[-1] if @{$self->{stop}};
+	return defined($stop) && $token->[0] =~ $stop;
+}
+
+sub expect {
+	my ($self, $expect) = @_;
+	my $token = $self->next_token();
+	return $token if defined($token) && $token->[0] eq $expect;
+	push(@{$self->{output}}, "?!ERR?! expected '$expect' but found '" . (defined($token) ? $token->[0] : "<end-of-input>") . "'\n");
+	$self->untoken($token) if defined($token);
+	return ();
+}
+
+sub optional_newlines {
+	my $self = shift @_;
+	my @tokens;
+	while (my $token = $self->peek()) {
+		last unless $token->[0] eq "\n";
+		push(@tokens, $self->next_token());
+	}
+	return @tokens;
+}
+
+sub parse_group {
+	my $self = shift @_;
+	return ($self->parse(qr/^}$/),
+		$self->expect('}'));
+}
+
+sub parse_subshell {
+	my $self = shift @_;
+	$self->{insubshell}++;
+	my @tokens = ($self->parse(qr/^\)$/),
+		      $self->expect(')'));
+	$self->{insubshell}--;
+	return @tokens;
+}
+
+sub parse_case_pattern {
+	my $self = shift @_;
+	my @tokens;
+	while (defined(my $token = $self->next_token())) {
+		push(@tokens, $token);
+		last if $token->[0] eq ')';
+	}
+	return @tokens;
+}
+
+sub parse_case {
+	my $self = shift @_;
+	my @tokens;
+	push(@tokens,
+	     $self->next_token(), # subject
+	     $self->optional_newlines(),
+	     $self->expect('in'),
+	     $self->optional_newlines());
+	while (1) {
+		my $token = $self->peek();
+		last unless defined($token) && $token->[0] ne 'esac';
+		push(@tokens,
+		     $self->parse_case_pattern(),
+		     $self->optional_newlines(),
+		     $self->parse(qr/^(?:;;|esac)$/)); # item body
+		$token = $self->peek();
+		last unless defined($token) && $token->[0] ne 'esac';
+		push(@tokens,
+		     $self->expect(';;'),
+		     $self->optional_newlines());
+	}
+	push(@tokens, $self->expect('esac'));
+	return @tokens;
+}
+
+sub parse_for {
+	my $self = shift @_;
+	my @tokens;
+	push(@tokens,
+	     $self->next_token(), # variable
+	     $self->optional_newlines());
+	my $token = $self->peek();
+	if (defined($token) && $token->[0] eq 'in') {
+		push(@tokens,
+		     $self->expect('in'),
+		     $self->optional_newlines());
+	}
+	push(@tokens,
+	     $self->parse(qr/^do$/), # items
+	     $self->expect('do'),
+	     $self->optional_newlines(),
+	     $self->parse_loop_body(),
+	     $self->expect('done'));
+	return @tokens;
+}
+
+sub parse_if {
+	my $self = shift @_;
+	my @tokens;
+	while (1) {
+		push(@tokens,
+		     $self->parse(qr/^then$/), # if/elif condition
+		     $self->expect('then'),
+		     $self->optional_newlines(),
+		     $self->parse(qr/^(?:elif|else|fi)$/)); # if/elif body
+		my $token = $self->peek();
+		last unless defined($token) && $token->[0] eq 'elif';
+		push(@tokens, $self->expect('elif'));
+	}
+	my $token = $self->peek();
+	if (defined($token) && $token->[0] eq 'else') {
+		push(@tokens,
+		     $self->expect('else'),
+		     $self->optional_newlines(),
+		     $self->parse(qr/^fi$/)); # else body
+	}
+	push(@tokens, $self->expect('fi'));
+	return @tokens;
+}
+
+sub parse_loop_body {
+	my $self = shift @_;
+	return $self->parse(qr/^done$/);
+}
+
+sub parse_loop {
+	my $self = shift @_;
+	return ($self->parse(qr/^do$/), # condition
+		$self->expect('do'),
+		$self->optional_newlines(),
+		$self->parse_loop_body(),
+		$self->expect('done'));
+}
+
+sub parse_func {
+	my $self = shift @_;
+	return ($self->expect('('),
+		$self->expect(')'),
+		$self->optional_newlines(),
+		$self->parse_cmd()); # body
+}
+
+sub parse_bash_array_assignment {
+	my $self = shift @_;
+	my @tokens = $self->expect('(');
+	while (defined(my $token = $self->next_token())) {
+		push(@tokens, $token);
+		last if $token->[0] eq ')';
+	}
+	return @tokens;
+}
+
+my %compound = (
+	'{' => \&parse_group,
+	'(' => \&parse_subshell,
+	'case' => \&parse_case,
+	'for' => \&parse_for,
+	'if' => \&parse_if,
+	'until' => \&parse_loop,
+	'while' => \&parse_loop);
+
+sub parse_cmd {
+	my $self = shift @_;
+	my $cmd = $self->next_token();
+	return () unless defined($cmd);
+	return $cmd if $cmd->[0] eq "\n";
+
+	my $token;
+	my @tokens = $cmd;
+	if ($cmd->[0] eq '!') {
+		push(@tokens, $self->parse_cmd());
+		return @tokens;
+	} elsif (my $f = $compound{$cmd->[0]}) {
+		push(@tokens, $self->$f());
+	} elsif (defined($token = $self->peek()) && $token->[0] eq '(') {
+		if ($cmd->[0] !~ /\w=$/) {
+			push(@tokens, $self->parse_func());
+			return @tokens;
+		}
+		my @array = $self->parse_bash_array_assignment();
+		$tokens[-1]->[0] .= join(' ', map {$_->[0]} @array);
+		$tokens[-1]->[2] = $array[$#array][2] if @array;
+	}
+
+	while (defined(my $token = $self->next_token())) {
+		$self->untoken($token), last if $self->stop_at($token);
+		push(@tokens, $token);
+		last if $token->[0] =~ /^(?:[;&\n|]|&&|\|\|)$/;
+	}
+	push(@tokens, $self->next_token()) if $tokens[-1]->[0] ne "\n" && defined($token = $self->peek()) && $token->[0] eq "\n";
+	return @tokens;
+}
+
+sub accumulate {
+	my ($self, $tokens, $cmd) = @_;
+	push(@$tokens, @$cmd);
+}
+
+sub parse {
+	my ($self, $stop) = @_;
+	push(@{$self->{stop}}, $stop);
+	goto DONE if $self->stop_at($self->peek());
+	my @tokens;
+	while (my @cmd = $self->parse_cmd()) {
+		$self->accumulate(\@tokens, \@cmd);
+		last if $self->stop_at($self->peek());
+	}
+DONE:
+	pop(@{$self->{stop}});
+	return @tokens;
+}
+
+# ScriptParser is a subclass of ShellParser which identifies individual test
+# definitions within test scripts and calls check_test() for each test body
+# found.  Callers subclass ScriptParser and override check_test() to
+# implement specific checks (e.g. chainlint checks &&-chains, lint-style
+# checks grep usage).
+package ScriptParser;
+
+our @ISA = ('ShellParser');
+
+# extract the raw content of a token, which may be a single string or a
+# composition of multiple strings and non-string character runs; for instance,
+# `"test body"` unwraps to `test body`; `word"a b"42'c d'` to `worda b42c d`
+sub unwrap {
+	my $token = (@_ ? shift @_ : $_)->[0];
+	# simple case: 'sqstring' or "dqstring"
+	return $token if $token =~ s/^'([^']*)'$/$1/;
+	return $token if $token =~ s/^"([^"]*)"$/$1/;
+
+	# composite case
+	my ($s, $q, $escaped);
+	while (1) {
+		# slurp up non-special characters
+		$s .= $1 if $token =~ /\G([^\\'"]*)/gc;
+		# handle special characters
+		last unless $token =~ /\G(.)/sgc;
+		my $c = $1;
+		$q = undef, next if defined($q) && $c eq $q;
+		$q = $c, next if !defined($q) && $c =~ /^['"]$/;
+		if ($c eq '\\') {
+			last unless $token =~ /\G(.)/sgc;
+			$c = $1;
+			$s .= '\\' if $c eq "\n"; # preserve line splice
+		}
+		$s .= $c;
+	}
+	return $s
+}
+
+sub check_test {
+	# no-op; subclasses override to implement specific checks
+}
+
+sub parse_cmd {
+	my $self = shift @_;
+	my @tokens = $self->SUPER::parse_cmd();
+	return @tokens unless @tokens && $tokens[0]->[0] =~ /^test_expect_(?:success|failure)$/;
+	my $n = $#tokens;
+	$n-- while $n >= 0 && $tokens[$n]->[0] =~ /^(?:[;&\n|]|&&|\|\|)$/;
+	my $herebody;
+	if ($n >= 2 && $tokens[$n-1]->[0] eq '-' && $tokens[$n]->[0] =~ /^<<-?(.+)$/) {
+		$herebody = $self->{heredocs}->{$1};
+		$n--;
+	}
+	$self->check_test($tokens[1], $tokens[2], $herebody) if $n == 2; # title body
+	$self->check_test($tokens[2], $tokens[3], $herebody) if $n > 2;  # prereq title body
+	return @tokens;
+}
+
+1;
-- 
gitgitgadget

[PATCH 3/6] t: fix Lexer line count for $() inside double-quoted strings

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

scan_dqstring's post-loop newline counter re-counts newlines that
were already counted during recursive parsing of $() bodies.  This
happens because scan_dollar's returned text can contain newlines
(from token text of multi-line strings and from \n command separator
tokens), and the catch-all counter at the end of scan_dqstring
counts all of them again.

Fix this by counting newlines inline as non-special characters are
consumed, and removing the post-loop catch-all.  Each newline is
now counted exactly once: literal newlines at the inline match,
line splices at the \<newline> handler, and $() newlines by
scan_token during the recursive parse.

This does not affect chainlint's output because chainlint annotates
the original body text using byte offsets, not token line numbers.
It does matter for tools like lint-style.pl (introduced in a
subsequent commit) that use token line numbers to locate and fix
specific lines in the original file.

Add check-shell-parser.pl to verify that the Lexer reports correct
line numbers after multi-line $() in double-quoted strings.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 t/Makefile              |  7 +++--
 t/check-shell-parser.pl | 58 +++++++++++++++++++++++++++++++++++++++++
 t/lib-shell-parser.pl   | 11 +++++---
 3 files changed, 71 insertions(+), 5 deletions(-)
 create mode 100644 t/check-shell-parser.pl

diff --git a/t/Makefile b/t/Makefile
index ab8a5b54aa..25f923fed9 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -139,7 +139,7 @@ check-meson:
 test-lint: test-lint-duplicates test-lint-executable \
 	test-lint-filenames
 ifneq ($(PERL_PATH),)
-test-lint: test-lint-shell-syntax
+test-lint: test-lint-shell-syntax check-shell-parser
 else
 GIT_TEST_CHAIN_LINT = 0
 endif
@@ -160,6 +160,8 @@ test-lint-executable:
 test-lint-shell-syntax:
 	@'$(PERL_PATH_SQ)' check-non-portable-shell.pl $(T) $(THELPERS) $(TPERF)
 
+check-shell-parser:
+	@'$(PERL_PATH_SQ)' check-shell-parser.pl
 test-lint-filenames:
 	@# We do *not* pass a glob to ls-files but use grep instead, to catch
 	@# non-ASCII characters (which are quoted within double-quotes)
@@ -185,7 +187,8 @@ perf:
 	$(MAKE) -C perf/ all
 
 .PHONY: pre-clean $(T) aggregate-results clean valgrind perf \
-	check-chainlint clean-chainlint test-chainlint $(UNIT_TESTS)
+	check-chainlint clean-chainlint test-chainlint \
+	check-shell-parser $(UNIT_TESTS)
 
 .PHONY: libgit-sys-test libgit-rs-test
 libgit-sys-test:
diff --git a/t/check-shell-parser.pl b/t/check-shell-parser.pl
new file mode 100644
index 0000000000..7d4ba6da7f
--- /dev/null
+++ b/t/check-shell-parser.pl
@@ -0,0 +1,58 @@
+#!/usr/bin/perl
+
+# Tests for the shared shell parser (lib-shell-parser.pl).
+
+use strict;
+use warnings;
+use File::Basename;
+
+my $_lib = dirname($0) . "/lib-shell-parser.pl";
+$_lib = "./$_lib" unless $_lib =~ m{^/};
+do $_lib or die "$0: failed to load $_lib: $@$!\n";
+
+my $rc = 0;
+
+sub check {
+	my ($desc, $body, $want_token, $want_line) = @_;
+	my $parser = ShellParser->new(\$body);
+	my @tokens = $parser->parse();
+	for my $t (reverse @tokens) {
+		next unless $t->[0] eq $want_token && defined $t->[3];
+		if ($t->[3] != $want_line) {
+			print STDERR "FAIL: $desc: " .
+				"'$want_token' at line $t->[3], " .
+				"expected line $want_line\n";
+			$rc = 1;
+		}
+		return;
+	}
+	print STDERR "FAIL: $desc: token '$want_token' not found\n";
+	$rc = 1;
+}
+
+# Multi-line $() inside a dq-string: MARKER should be at line 3.
+check('dq-string with multi-line $()', <<'BODY', 'MARKER', 3);
+	x="$(echo one
+	echo two)" &&
+	MARKER here
+BODY
+
+# Two multi-line $() substitutions: verifies drift does not accumulate.
+# MARKER should be at line 5.
+check('two dq-string $()', <<'BODY', 'MARKER', 5);
+	x="$(echo a
+	b)" &&
+	y="$(echo c
+	d)" &&
+	MARKER here
+BODY
+
+# $() outside a dq-string: no double-counting either way.
+# MARKER should be at line 3.
+check('bare $() spanning lines', <<'BODY', 'MARKER', 3);
+	x=$(echo one
+	echo two) &&
+	MARKER here
+BODY
+
+exit $rc;
diff --git a/t/lib-shell-parser.pl b/t/lib-shell-parser.pl
index 1e521a94f8..fa9b44d6ec 100644
--- a/t/lib-shell-parser.pl
+++ b/t/lib-shell-parser.pl
@@ -89,8 +89,14 @@ sub scan_dqstring {
 	my $b = $self->{buff};
 	my $s = '"';
 	while (1) {
-		# slurp up non-special characters
-		$s .= $1 if $$b =~ /\G([^"\$\\]+)/gc;
+		# slurp up non-special characters; count newlines
+		# inline so we don't need a catch-all counter that
+		# would miscount newlines from recursive $() parsing
+		if ($$b =~ /\G([^"\$\\]+)/gc) {
+			my $chunk = $1;
+			$self->{lineno} += () = $chunk =~ /\n/sg;
+			$s .= $chunk;
+		}
 		# handle special characters
 		last unless $$b =~ /\G(.)/sgc;
 		my $c = $1;
@@ -107,7 +113,6 @@ sub scan_dqstring {
 		}
 		die("internal error scanning dq-string '$c'\n");
 	}
-	$self->{lineno} += () = $s =~ /\n/sg;
 	return $s;
 }
 
-- 
gitgitgadget

[PATCH 4/6] t: add lint-style.pl with test_grep negation rule

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

Add a mechanical lint checker for test scripts, similar in spirit to
check-non-portable-shell.pl but focused on test conventions rather
than portability.

The tool defines LintParser, a subclass of ScriptParser (from the
shared lib-shell-parser.pl module).  ScriptParser's
parse_cmd() finds test_expect_success blocks and calls check_test()
for each body; LintParser overrides check_test() to run lint rules
on the parsed commands.  A "# lint-ok" comment suppresses all
checks for intentional style violations.

The first rule detects '! test_grep' and replaces it with
'test_grep !'.  Shell-level negation suppresses the diagnostic
output that test_grep prints on failure; the built-in negation
preserves it.

Three violations inside test bodies are converted via --fix.  One
additional violation in a helper function outside test_expect_success
(t7900's test_geometric_repack_needed) is converted manually, since
the parser only processes test bodies.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 t/.gitattributes                           |   2 +
 t/Makefile                                 |  32 +++-
 t/lint-style.pl                            | 200 +++++++++++++++++++++
 t/lint-style/heredoc.expect                |   3 +
 t/lint-style/heredoc.test                  |  14 ++
 t/lint-style/test-grep-negation-fix.expect |   4 +
 t/lint-style/test-grep-negation-fix.test   |   4 +
 t/lint-style/test-grep-negation.expect     |   3 +
 t/lint-style/test-grep-negation.test       |   4 +
 t/t0031-lockfile-pid.sh                    |   2 +-
 t/t5300-pack-object.sh                     |   2 +-
 t/t5319-multi-pack-index.sh                |   2 +-
 t/t7900-maintenance.sh                     |   2 +-
 13 files changed, 268 insertions(+), 6 deletions(-)
 create mode 100755 t/lint-style.pl
 create mode 100644 t/lint-style/heredoc.expect
 create mode 100644 t/lint-style/heredoc.test
 create mode 100644 t/lint-style/test-grep-negation-fix.expect
 create mode 100644 t/lint-style/test-grep-negation-fix.test
 create mode 100644 t/lint-style/test-grep-negation.expect
 create mode 100644 t/lint-style/test-grep-negation.test

diff --git a/t/.gitattributes b/t/.gitattributes
index 7664c6e027..aea6889d03 100644
--- a/t/.gitattributes
+++ b/t/.gitattributes
@@ -1,5 +1,7 @@
 t[0-9][0-9][0-9][0-9]/* -whitespace
 /chainlint/*.expect eol=lf -whitespace
+/lint-style/*.expect eol=lf -whitespace
+/lint-style/*.test eol=lf -whitespace
 /t0110/url-* binary
 /t3206/* eol=lf
 /t3900/*.txt eol=lf
diff --git a/t/Makefile b/t/Makefile
index 25f923fed9..3a5fa4ce37 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -46,6 +46,7 @@ TPERF = $(sort $(wildcard perf/p[0-9][0-9][0-9][0-9]-*.sh))
 TINTEROP = $(sort $(wildcard interop/i[0-9][0-9][0-9][0-9]-*.sh))
 CHAINLINTTESTS = $(sort $(patsubst chainlint/%.test,%,$(wildcard chainlint/*.test)))
 CHAINLINT = '$(PERL_PATH_SQ)' chainlint.pl
+LINT_STYLE_TESTS = $(sort $(wildcard lint-style/*.test))
 UNIT_TEST_SOURCES = $(wildcard unit-tests/t-*.c)
 UNIT_TEST_PROGRAMS = $(patsubst unit-tests/%.c,unit-tests/bin/%$(X),$(UNIT_TEST_SOURCES))
 UNIT_TEST_PROGRAMS += unit-tests/bin/unit-tests$(X)
@@ -139,7 +140,7 @@ check-meson:
 test-lint: test-lint-duplicates test-lint-executable \
 	test-lint-filenames
 ifneq ($(PERL_PATH),)
-test-lint: test-lint-shell-syntax check-shell-parser
+test-lint: test-lint-shell-syntax test-lint-style check-lint-style check-shell-parser
 else
 GIT_TEST_CHAIN_LINT = 0
 endif
@@ -162,6 +163,32 @@ test-lint-shell-syntax:
 
 check-shell-parser:
 	@'$(PERL_PATH_SQ)' check-shell-parser.pl
+
+test-lint-style:
+	@'$(PERL_PATH_SQ)' lint-style.pl $(T) $(THELPERS) $(TPERF)
+
+check-lint-style:
+	@rc=0; for t in $(LINT_STYLE_TESTS); do \
+		base=$${t%.test}; \
+		case $$base in \
+		*-fix) \
+			cp "$$t" "$$t.tmp" && \
+			'$(PERL_PATH_SQ)' lint-style.pl --fix "$$t.tmp" >/dev/null 2>&1; \
+			fix_rc=$$?; \
+			if test $$fix_rc != 0; then \
+				echo "FAIL: $$t (--fix exit code $$fix_rc)"; rc=1; \
+			elif ! diff -u "$$base.expect" "$$t.tmp"; then \
+				echo "FAIL: $$t (--fix output)"; rc=1; \
+			fi; \
+			rm -f "$$t.tmp" ;; \
+		*) \
+			if ! '$(PERL_PATH_SQ)' lint-style.pl "$$t" 2>&1 | \
+				diff -u "$$base.expect" -; then \
+				echo "FAIL: $$t"; rc=1; \
+			fi ;; \
+		esac; \
+	done; test $$rc = 0
+
 test-lint-filenames:
 	@# We do *not* pass a glob to ls-files but use grep instead, to catch
 	@# non-ASCII characters (which are quoted within double-quotes)
@@ -188,7 +215,8 @@ perf:
 
 .PHONY: pre-clean $(T) aggregate-results clean valgrind perf \
 	check-chainlint clean-chainlint test-chainlint \
-	check-shell-parser $(UNIT_TESTS)
+	check-shell-parser \
+	check-lint-style test-lint-style $(UNIT_TESTS)
 
 .PHONY: libgit-sys-test libgit-rs-test
 libgit-sys-test:
diff --git a/t/lint-style.pl b/t/lint-style.pl
new file mode 100755
index 0000000000..9268577f9b
--- /dev/null
+++ b/t/lint-style.pl
@@ -0,0 +1,200 @@
+#!/usr/bin/perl
+
+# Check test scripts for style violations that can be detected
+# mechanically, such as using bare 'grep' where test_grep should
+# be used.  Use --fix to automatically apply suggested replacements.
+#
+# Detection uses parsed tokens from the shared shell parser for
+# correct handling of heredocs, $(...), pipes, and quoting.
+# Fixes modify the original file text to preserve formatting.
+
+use strict;
+use warnings;
+use File::Basename;
+# Force LF output so check-lint-style's diff against the
+# pre-committed .expect files works on Windows.
+binmode(STDOUT, ':unix');
+binmode(STDERR, ':unix');
+
+my $fix_mode = 0;
+if (@ARGV && $ARGV[0] eq '--fix') {
+	$fix_mode = 1;
+	shift @ARGV;
+}
+
+# Load the shared shell parser (Lexer, ShellParser, ScriptParser).
+my $_lib = dirname($0) . "/lib-shell-parser.pl";
+$_lib = "./$_lib" unless $_lib =~ m{^/};
+do $_lib or die "$0: failed to load $_lib: $@$!\n";
+
+# LintParser is a subclass of ScriptParser which runs lint rules
+# on each test body.  Per-file state (file name, raw lines, dirty
+# flag) is stored on the instance before calling parse().
+#
+# Subroutines defined below (parse_commands, check_test_grep_negation,
+# etc.) are in package main and called with the main:: prefix.
+# File-scoped lexicals ($fix_mode, $has_fixable, etc.) are visible
+# across packages since 'package' does not introduce a new scope.
+package LintParser;
+our @ISA = ('ScriptParser');
+
+package main;
+
+my $exit_code = 0;
+my $has_fixable = 0;
+
+sub err {
+	my ($file, $lineno, $line, $msg, %opts) = @_;
+	$line =~ s/^\s+//;
+	$line =~ s/\s+$//;
+	$line =~ s/\s+/ /g;
+	my $prefix = ($fix_mode && $opts{fixable}) ? 'fixed' : 'error';
+	print "$file:$lineno: $prefix: $msg: $line\n";
+	$exit_code = 1 unless $fix_mode && $opts{fixable};
+}
+
+# Report a lint violation found by a rule.  In --fix mode, apply
+# the regex substitution on the raw line and report success.
+# Otherwise just report.  Returns 1 if the line was modified.
+sub report_violation {
+	my ($file, $cmd, $line_ref, $match, $fix, $from) = @_;
+	my $lineno = $cmd->{lineno};
+	my $display = join(' ', @{$cmd->{tokens}});
+	$has_fixable++;  # count for the "--fix" hint
+	if ($fix_mode) {
+		if ($$line_ref =~ s/$match/$fix/) {
+			err $file, $lineno, $display,
+				"replace '$from' with '$fix'",
+				fixable => 1;
+			return 1;
+		}
+		err $file, $lineno, $display,
+			"replace '$from' with '$fix' (could not auto-fix)";
+	} else {
+		err $file, $lineno, $display,
+			"replace '$from' with '$fix'";
+	}
+	return 0;
+}
+
+# Split a token stream into commands at &&, ||, ;;, and \n.
+sub parse_commands {
+	my ($content) = @_;
+	my $parser = ShellParser->new(\$content);
+	my @all_tokens = $parser->parse();
+
+	my @commands;
+	my @current;
+	my $lineno = 1;
+
+	for (my $ti = 0; $ti < @all_tokens; $ti++) {
+		my $text = $all_tokens[$ti]->[0];
+		if ($text =~ /^(?:&&|\|\||;;|\n)$/) {
+			if (@current) {
+				push @commands, {
+					tokens => [@current],
+					lineno => $lineno,
+				};
+				@current = ();
+			}
+		} else {
+			$lineno = $all_tokens[$ti]->[3]
+				if !@current && defined $all_tokens[$ti]->[3];
+			push @current, $text;
+		}
+	}
+	if (@current) {
+		push @commands, {
+			tokens => [@current],
+			lineno => $lineno,
+		};
+	}
+	return @commands;
+}
+
+# --- Rule: '! test_grep' should be 'test_grep !' ---
+# Shell-level negation suppresses test_grep's diagnostic output
+# on failure.  Built-in negation preserves it.
+sub check_test_grep_negation {
+	my ($cmd, $file, $line_ref) = @_;
+	my @tokens = @{$cmd->{tokens}};
+	return unless @tokens >= 2 && $tokens[0] eq '!' && $tokens[1] eq 'test_grep';
+
+	return report_violation($file, $cmd, $line_ref,
+		qr/!\s*test_grep/, 'test_grep !', '! test_grep');
+}
+
+# Map parsed commands back to raw file lines for --fix.
+# Detection uses parsed tokens (correct handling of quoting,
+# heredocs, pipes) but fixes must modify the original text
+# to preserve formatting.
+package LintParser;
+
+sub check_test {
+	# Called by ScriptParser::parse_cmd for each test_expect_success
+	# or test_expect_failure block.
+	my $self = shift @_;
+	my $title = ScriptParser::unwrap(shift @_);
+
+	# Two test body formats:
+	#   Quoted:  test_expect_success 'title' '..body..'
+	#   Heredoc: test_expect_success 'title' - <<\EOF
+	#              ..body..
+	#            EOF
+	# For quoted, the body token is the quoted string.
+	# For heredoc, the body token is '-' and the actual
+	# code arrives as the next argument from the Lexer.
+	my $body_token = shift @_;
+	my $lineno_base = $body_token->[3] || 1;
+	my $body = ScriptParser::unwrap($body_token);
+
+	if ($body eq '-') {
+		my $herebody = shift @_;
+		if ($herebody) {
+			$body = $herebody->{content};
+			$lineno_base = $herebody->{start_line} || 1;
+		}
+	}
+	return unless $body;
+
+	# Map each command back to its file line number.
+	# $lineno_base is where the body starts in the file;
+	# $cmd->{lineno} is relative to the body (starting at 1).
+	my $raw_lines = $self->{raw_lines};
+	for my $cmd (main::parse_commands($body)) {
+		my $ln = ($cmd->{lineno} || 0) + $lineno_base - 1;
+		$cmd->{lineno} = $ln;
+		next unless $ln >= 1 && $ln <= @$raw_lines;
+		next if $raw_lines->[$ln - 1] =~ /#.*lint-ok/;
+
+		if (main::check_test_grep_negation($cmd, $self->{file}, \$raw_lines->[$ln - 1])) {
+			$self->{dirty} = 1;
+		}
+	}
+}
+
+package main;
+
+for my $file (@ARGV) {
+	# :unix:crlf strips \r on Windows (same as chainlint.pl)
+	open(my $fh, '<:unix:crlf', $file) or die "$0: $file: $!\n";
+	my @raw_lines = <$fh>;
+	close $fh;
+
+	my $parser = LintParser->new(\join('', @raw_lines));
+	$parser->{file} = $file;
+	$parser->{raw_lines} = \@raw_lines;
+	$parser->{dirty} = 0;
+	$parser->parse();
+
+	if ($fix_mode && $parser->{dirty}) {
+		open(my $out, '>', $file) or die "$0: $file: $!\n";
+		print $out @{$parser->{raw_lines}};
+		close $out;
+	}
+}
+
+if ($has_fixable && !$fix_mode) {
+	print "hint: run with --fix to apply the suggested replacements.\n";
+}
+exit $exit_code;
diff --git a/t/lint-style/heredoc.expect b/t/lint-style/heredoc.expect
new file mode 100644
index 0000000000..7ff6d4a52d
--- /dev/null
+++ b/t/lint-style/heredoc.expect
@@ -0,0 +1,3 @@
+lint-style/heredoc.test:8: error: replace '! test_grep' with 'test_grep !': ! test_grep "after-heredoc-is-caught" actual
+lint-style/heredoc.test:13: error: replace '! test_grep' with 'test_grep !': ! test_grep "not-inside-sed-heredoc" actual
+hint: run with --fix to apply the suggested replacements.
diff --git a/t/lint-style/heredoc.test b/t/lint-style/heredoc.test
new file mode 100644
index 0000000000..4c05831cfb
--- /dev/null
+++ b/t/lint-style/heredoc.test
@@ -0,0 +1,14 @@
+test_expect_success 'greps inside heredocs are skipped' '
+	cat <<-EOF &&
+	grep "inside-strip-tabs" file
+	EOF
+	cat <<-\EOF &&
+	grep "inside-no-expand" file
+	EOF
+	! test_grep "after-heredoc-is-caught" actual
+'
+
+test_expect_success 'sed with << does not start a heredoc' '
+	sed "s/<< foo/bar/" file &&
+	! test_grep "not-inside-sed-heredoc" actual
+'
diff --git a/t/lint-style/test-grep-negation-fix.expect b/t/lint-style/test-grep-negation-fix.expect
new file mode 100644
index 0000000000..28ecde1073
--- /dev/null
+++ b/t/lint-style/test-grep-negation-fix.expect
@@ -0,0 +1,4 @@
+test_expect_success 'negated test_grep' '
+	test_grep ! "pattern" actual &&
+	test_grep ! -i "insensitive" actual
+'
diff --git a/t/lint-style/test-grep-negation-fix.test b/t/lint-style/test-grep-negation-fix.test
new file mode 100644
index 0000000000..571c150031
--- /dev/null
+++ b/t/lint-style/test-grep-negation-fix.test
@@ -0,0 +1,4 @@
+test_expect_success 'negated test_grep' '
+	! test_grep "pattern" actual &&
+	! test_grep -i "insensitive" actual
+'
diff --git a/t/lint-style/test-grep-negation.expect b/t/lint-style/test-grep-negation.expect
new file mode 100644
index 0000000000..1fa9e124aa
--- /dev/null
+++ b/t/lint-style/test-grep-negation.expect
@@ -0,0 +1,3 @@
+lint-style/test-grep-negation.test:2: error: replace '! test_grep' with 'test_grep !': ! test_grep "pattern" actual
+lint-style/test-grep-negation.test:3: error: replace '! test_grep' with 'test_grep !': ! test_grep -i "insensitive" actual
+hint: run with --fix to apply the suggested replacements.
diff --git a/t/lint-style/test-grep-negation.test b/t/lint-style/test-grep-negation.test
new file mode 100644
index 0000000000..571c150031
--- /dev/null
+++ b/t/lint-style/test-grep-negation.test
@@ -0,0 +1,4 @@
+test_expect_success 'negated test_grep' '
+	! test_grep "pattern" actual &&
+	! test_grep -i "insensitive" actual
+'
diff --git a/t/t0031-lockfile-pid.sh b/t/t0031-lockfile-pid.sh
index 8ef87addf5..e9e2f04049 100755
--- a/t/t0031-lockfile-pid.sh
+++ b/t/t0031-lockfile-pid.sh
@@ -29,7 +29,7 @@ test_expect_success 'PID info not shown by default' '
 		test_must_fail git add . 2>err &&
 		# Should not crash, just show normal error without PID
 		test_grep "Unable to create" err &&
-		! test_grep "is held by process" err
+		test_grep ! "is held by process" err
 	)
 '
 
diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
index 73445782e7..3179b4963e 100755
--- a/t/t5300-pack-object.sh
+++ b/t/t5300-pack-object.sh
@@ -720,7 +720,7 @@ test_expect_success '--name-hash-version=2 and --write-bitmap-index are incompat
 
 	# --stdout option silently removes --write-bitmap-index
 	git pack-objects --stdout --all --name-hash-version=2 --write-bitmap-index >out 2>err &&
-	! test_grep "currently, --write-bitmap-index requires --name-hash-version=1" err
+	test_grep ! "currently, --write-bitmap-index requires --name-hash-version=1" err
 '
 
 test_expect_success '--path-walk pack everything' '
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index fa0d4046f7..9154d9795f 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -1175,7 +1175,7 @@ test_expect_success 'load reverse index when missing .idx, .pack' '
 
 test_expect_success 'usage shown without sub-command' '
 	test_expect_code 129 git multi-pack-index 2>err &&
-	! test_grep "unrecognized subcommand" err
+	test_grep ! "unrecognized subcommand" err
 '
 
 test_expect_success 'complains when run outside of a repository' '
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index d7f82e1bec..9db4a76f67 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -664,7 +664,7 @@ test_geometric_repack_needed () {
 	true)
 		test_grep "\[\"git\",\"repack\"," trace2.txt;;
 	false)
-		! test_grep "\[\"git\",\"repack\"," trace2.txt;;
+		test_grep ! "\[\"git\",\"repack\"," trace2.txt;;
 	*)
 		BUG "invalid parameter: $NEEDED";;
 	esac
-- 
gitgitgadget

Re: [PATCH 4/6] t: add lint-style.pl with test_grep negation rule

[D. Ben Knoble]

Hi Michael,

This sounds like a neat effort!

One drive-by comment…

On Thu, Jun 4, 2026 at 3:46 AM Michael Montalbo via GitGitGadget
<gitgitgadget@gmail.com> wrote:
>
> From: Michael Montalbo <mmontalbo@gmail.com>
>
> Add a mechanical lint checker for test scripts, similar in spirit to
> check-non-portable-shell.pl but focused on test conventions rather
> than portability.
>
> The tool defines LintParser, a subclass of ScriptParser (from the
> shared lib-shell-parser.pl module).  ScriptParser's
> parse_cmd() finds test_expect_success blocks and calls check_test()
> for each body; LintParser overrides check_test() to run lint rules
> on the parsed commands.  A "# lint-ok" comment suppresses all
> checks for intentional style violations.
>
> The first rule detects '! test_grep' and replaces it with
> 'test_grep !'.  Shell-level negation suppresses the diagnostic
> output that test_grep prints on failure; the built-in negation
> preserves it.
>
> Three violations inside test bodies are converted via --fix.  One
> additional violation in a helper function outside test_expect_success
> (t7900's test_geometric_repack_needed) is converted manually, since
> the parser only processes test bodies.
>
> Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
> ---
>  t/.gitattributes                           |   2 +
>  t/Makefile                                 |  32 +++-
>  t/lint-style.pl                            | 200 +++++++++++++++++++++
>  t/lint-style/heredoc.expect                |   3 +
>  t/lint-style/heredoc.test                  |  14 ++
>  t/lint-style/test-grep-negation-fix.expect |   4 +
>  t/lint-style/test-grep-negation-fix.test   |   4 +
>  t/lint-style/test-grep-negation.expect     |   3 +
>  t/lint-style/test-grep-negation.test       |   4 +
>  t/t0031-lockfile-pid.sh                    |   2 +-
>  t/t5300-pack-object.sh                     |   2 +-
>  t/t5319-multi-pack-index.sh                |   2 +-
>  t/t7900-maintenance.sh                     |   2 +-
>  13 files changed, 268 insertions(+), 6 deletions(-)
>  create mode 100755 t/lint-style.pl
>  create mode 100644 t/lint-style/heredoc.expect
>  create mode 100644 t/lint-style/heredoc.test
>  create mode 100644 t/lint-style/test-grep-negation-fix.expect
>  create mode 100644 t/lint-style/test-grep-negation-fix.test
>  create mode 100644 t/lint-style/test-grep-negation.expect
>  create mode 100644 t/lint-style/test-grep-negation.test
>
> diff --git a/t/.gitattributes b/t/.gitattributes
> index 7664c6e027..aea6889d03 100644
> --- a/t/.gitattributes
> +++ b/t/.gitattributes
> @@ -1,5 +1,7 @@
>  t[0-9][0-9][0-9][0-9]/* -whitespace
>  /chainlint/*.expect eol=lf -whitespace
> +/lint-style/*.expect eol=lf -whitespace
> +/lint-style/*.test eol=lf -whitespace
>  /t0110/url-* binary
>  /t3206/* eol=lf
>  /t3900/*.txt eol=lf
> diff --git a/t/Makefile b/t/Makefile
> index 25f923fed9..3a5fa4ce37 100644
> --- a/t/Makefile
> +++ b/t/Makefile
> @@ -46,6 +46,7 @@ TPERF = $(sort $(wildcard perf/p[0-9][0-9][0-9][0-9]-*.sh))
>  TINTEROP = $(sort $(wildcard interop/i[0-9][0-9][0-9][0-9]-*.sh))
>  CHAINLINTTESTS = $(sort $(patsubst chainlint/%.test,%,$(wildcard chainlint/*.test)))
>  CHAINLINT = '$(PERL_PATH_SQ)' chainlint.pl
> +LINT_STYLE_TESTS = $(sort $(wildcard lint-style/*.test))
>  UNIT_TEST_SOURCES = $(wildcard unit-tests/t-*.c)
>  UNIT_TEST_PROGRAMS = $(patsubst unit-tests/%.c,unit-tests/bin/%$(X),$(UNIT_TEST_SOURCES))
>  UNIT_TEST_PROGRAMS += unit-tests/bin/unit-tests$(X)
> @@ -139,7 +140,7 @@ check-meson:
>  test-lint: test-lint-duplicates test-lint-executable \
>         test-lint-filenames
>  ifneq ($(PERL_PATH),)
> -test-lint: test-lint-shell-syntax check-shell-parser
> +test-lint: test-lint-shell-syntax test-lint-style check-lint-style check-shell-parser
>  else
>  GIT_TEST_CHAIN_LINT = 0
>  endif
> @@ -162,6 +163,32 @@ test-lint-shell-syntax:
>
>  check-shell-parser:
>         @'$(PERL_PATH_SQ)' check-shell-parser.pl
> +
> +test-lint-style:
> +       @'$(PERL_PATH_SQ)' lint-style.pl $(T) $(THELPERS) $(TPERF)
> +
> +check-lint-style:
> +       @rc=0; for t in $(LINT_STYLE_TESTS); do \
> +               base=$${t%.test}; \
> +               case $$base in \
> +               *-fix) \
> +                       cp "$$t" "$$t.tmp" && \
> +                       '$(PERL_PATH_SQ)' lint-style.pl --fix "$$t.tmp" >/dev/null 2>&1; \
> +                       fix_rc=$$?; \
> +                       if test $$fix_rc != 0; then \
> +                               echo "FAIL: $$t (--fix exit code $$fix_rc)"; rc=1; \
> +                       elif ! diff -u "$$base.expect" "$$t.tmp"; then \
> +                               echo "FAIL: $$t (--fix output)"; rc=1; \
> +                       fi; \
> +                       rm -f "$$t.tmp" ;; \
> +               *) \
> +                       if ! '$(PERL_PATH_SQ)' lint-style.pl "$$t" 2>&1 | \
> +                               diff -u "$$base.expect" -; then \
> +                               echo "FAIL: $$t"; rc=1; \
> +                       fi ;; \
> +               esac; \
> +       done; test $$rc = 0
> +

…I wonder if it would be easier to maintain this recipe as a separate
shell script and have make give LINT_STYLE_TESTS and PERL_PATH (w/o
SQ? idk) to the script. That's a lot of inline code otherwise!

>  test-lint-filenames:
>         @# We do *not* pass a glob to ls-files but use grep instead, to catch
>         @# non-ASCII characters (which are quoted within double-quotes)
> @@ -188,7 +215,8 @@ perf:
>
>  .PHONY: pre-clean $(T) aggregate-results clean valgrind perf \
>         check-chainlint clean-chainlint test-chainlint \
> -       check-shell-parser $(UNIT_TESTS)
> +       check-shell-parser \
> +       check-lint-style test-lint-style $(UNIT_TESTS)
>
>  .PHONY: libgit-sys-test libgit-rs-test
>  libgit-sys-test:
> diff --git a/t/lint-style.pl b/t/lint-style.pl
> new file mode 100755
> index 0000000000..9268577f9b
> --- /dev/null
> +++ b/t/lint-style.pl
> @@ -0,0 +1,200 @@
> +#!/usr/bin/perl
> +
> +# Check test scripts for style violations that can be detected
> +# mechanically, such as using bare 'grep' where test_grep should
> +# be used.  Use --fix to automatically apply suggested replacements.
> +#
> +# Detection uses parsed tokens from the shared shell parser for
> +# correct handling of heredocs, $(...), pipes, and quoting.
> +# Fixes modify the original file text to preserve formatting.
> +
> +use strict;
> +use warnings;
> +use File::Basename;
> +# Force LF output so check-lint-style's diff against the
> +# pre-committed .expect files works on Windows.
> +binmode(STDOUT, ':unix');
> +binmode(STDERR, ':unix');
> +
> +my $fix_mode = 0;
> +if (@ARGV && $ARGV[0] eq '--fix') {
> +       $fix_mode = 1;
> +       shift @ARGV;
> +}
> +
> +# Load the shared shell parser (Lexer, ShellParser, ScriptParser).
> +my $_lib = dirname($0) . "/lib-shell-parser.pl";
> +$_lib = "./$_lib" unless $_lib =~ m{^/};
> +do $_lib or die "$0: failed to load $_lib: $@$!\n";
> +
> +# LintParser is a subclass of ScriptParser which runs lint rules
> +# on each test body.  Per-file state (file name, raw lines, dirty
> +# flag) is stored on the instance before calling parse().
> +#
> +# Subroutines defined below (parse_commands, check_test_grep_negation,
> +# etc.) are in package main and called with the main:: prefix.
> +# File-scoped lexicals ($fix_mode, $has_fixable, etc.) are visible
> +# across packages since 'package' does not introduce a new scope.
> +package LintParser;
> +our @ISA = ('ScriptParser');
> +
> +package main;
> +
> +my $exit_code = 0;
> +my $has_fixable = 0;
> +
> +sub err {
> +       my ($file, $lineno, $line, $msg, %opts) = @_;
> +       $line =~ s/^\s+//;
> +       $line =~ s/\s+$//;
> +       $line =~ s/\s+/ /g;
> +       my $prefix = ($fix_mode && $opts{fixable}) ? 'fixed' : 'error';
> +       print "$file:$lineno: $prefix: $msg: $line\n";
> +       $exit_code = 1 unless $fix_mode && $opts{fixable};
> +}
> +
> +# Report a lint violation found by a rule.  In --fix mode, apply
> +# the regex substitution on the raw line and report success.
> +# Otherwise just report.  Returns 1 if the line was modified.
> +sub report_violation {
> +       my ($file, $cmd, $line_ref, $match, $fix, $from) = @_;
> +       my $lineno = $cmd->{lineno};
> +       my $display = join(' ', @{$cmd->{tokens}});
> +       $has_fixable++;  # count for the "--fix" hint
> +       if ($fix_mode) {
> +               if ($$line_ref =~ s/$match/$fix/) {
> +                       err $file, $lineno, $display,
> +                               "replace '$from' with '$fix'",
> +                               fixable => 1;
> +                       return 1;
> +               }
> +               err $file, $lineno, $display,
> +                       "replace '$from' with '$fix' (could not auto-fix)";
> +       } else {
> +               err $file, $lineno, $display,
> +                       "replace '$from' with '$fix'";
> +       }
> +       return 0;
> +}
> +
> +# Split a token stream into commands at &&, ||, ;;, and \n.
> +sub parse_commands {
> +       my ($content) = @_;
> +       my $parser = ShellParser->new(\$content);
> +       my @all_tokens = $parser->parse();
> +
> +       my @commands;
> +       my @current;
> +       my $lineno = 1;
> +
> +       for (my $ti = 0; $ti < @all_tokens; $ti++) {
> +               my $text = $all_tokens[$ti]->[0];
> +               if ($text =~ /^(?:&&|\|\||;;|\n)$/) {
> +                       if (@current) {
> +                               push @commands, {
> +                                       tokens => [@current],
> +                                       lineno => $lineno,
> +                               };
> +                               @current = ();
> +                       }
> +               } else {
> +                       $lineno = $all_tokens[$ti]->[3]
> +                               if !@current && defined $all_tokens[$ti]->[3];
> +                       push @current, $text;
> +               }
> +       }
> +       if (@current) {
> +               push @commands, {
> +                       tokens => [@current],
> +                       lineno => $lineno,
> +               };
> +       }
> +       return @commands;
> +}
> +
> +# --- Rule: '! test_grep' should be 'test_grep !' ---
> +# Shell-level negation suppresses test_grep's diagnostic output
> +# on failure.  Built-in negation preserves it.
> +sub check_test_grep_negation {
> +       my ($cmd, $file, $line_ref) = @_;
> +       my @tokens = @{$cmd->{tokens}};
> +       return unless @tokens >= 2 && $tokens[0] eq '!' && $tokens[1] eq 'test_grep';
> +
> +       return report_violation($file, $cmd, $line_ref,
> +               qr/!\s*test_grep/, 'test_grep !', '! test_grep');
> +}
> +
> +# Map parsed commands back to raw file lines for --fix.
> +# Detection uses parsed tokens (correct handling of quoting,
> +# heredocs, pipes) but fixes must modify the original text
> +# to preserve formatting.
> +package LintParser;
> +
> +sub check_test {
> +       # Called by ScriptParser::parse_cmd for each test_expect_success
> +       # or test_expect_failure block.
> +       my $self = shift @_;
> +       my $title = ScriptParser::unwrap(shift @_);
> +
> +       # Two test body formats:
> +       #   Quoted:  test_expect_success 'title' '..body..'
> +       #   Heredoc: test_expect_success 'title' - <<\EOF
> +       #              ..body..
> +       #            EOF
> +       # For quoted, the body token is the quoted string.
> +       # For heredoc, the body token is '-' and the actual
> +       # code arrives as the next argument from the Lexer.
> +       my $body_token = shift @_;
> +       my $lineno_base = $body_token->[3] || 1;
> +       my $body = ScriptParser::unwrap($body_token);
> +
> +       if ($body eq '-') {
> +               my $herebody = shift @_;
> +               if ($herebody) {
> +                       $body = $herebody->{content};
> +                       $lineno_base = $herebody->{start_line} || 1;
> +               }
> +       }
> +       return unless $body;
> +
> +       # Map each command back to its file line number.
> +       # $lineno_base is where the body starts in the file;
> +       # $cmd->{lineno} is relative to the body (starting at 1).
> +       my $raw_lines = $self->{raw_lines};
> +       for my $cmd (main::parse_commands($body)) {
> +               my $ln = ($cmd->{lineno} || 0) + $lineno_base - 1;
> +               $cmd->{lineno} = $ln;
> +               next unless $ln >= 1 && $ln <= @$raw_lines;
> +               next if $raw_lines->[$ln - 1] =~ /#.*lint-ok/;
> +
> +               if (main::check_test_grep_negation($cmd, $self->{file}, \$raw_lines->[$ln - 1])) {
> +                       $self->{dirty} = 1;
> +               }
> +       }
> +}
> +
> +package main;
> +
> +for my $file (@ARGV) {
> +       # :unix:crlf strips \r on Windows (same as chainlint.pl)
> +       open(my $fh, '<:unix:crlf', $file) or die "$0: $file: $!\n";
> +       my @raw_lines = <$fh>;
> +       close $fh;
> +
> +       my $parser = LintParser->new(\join('', @raw_lines));
> +       $parser->{file} = $file;
> +       $parser->{raw_lines} = \@raw_lines;
> +       $parser->{dirty} = 0;
> +       $parser->parse();
> +
> +       if ($fix_mode && $parser->{dirty}) {
> +               open(my $out, '>', $file) or die "$0: $file: $!\n";
> +               print $out @{$parser->{raw_lines}};
> +               close $out;
> +       }
> +}
> +
> +if ($has_fixable && !$fix_mode) {
> +       print "hint: run with --fix to apply the suggested replacements.\n";
> +}
> +exit $exit_code;
> diff --git a/t/lint-style/heredoc.expect b/t/lint-style/heredoc.expect
> new file mode 100644
> index 0000000000..7ff6d4a52d
> --- /dev/null
> +++ b/t/lint-style/heredoc.expect
> @@ -0,0 +1,3 @@
> +lint-style/heredoc.test:8: error: replace '! test_grep' with 'test_grep !': ! test_grep "after-heredoc-is-caught" actual
> +lint-style/heredoc.test:13: error: replace '! test_grep' with 'test_grep !': ! test_grep "not-inside-sed-heredoc" actual
> +hint: run with --fix to apply the suggested replacements.
> diff --git a/t/lint-style/heredoc.test b/t/lint-style/heredoc.test
> new file mode 100644
> index 0000000000..4c05831cfb
> --- /dev/null
> +++ b/t/lint-style/heredoc.test
> @@ -0,0 +1,14 @@
> +test_expect_success 'greps inside heredocs are skipped' '
> +       cat <<-EOF &&
> +       grep "inside-strip-tabs" file
> +       EOF
> +       cat <<-\EOF &&
> +       grep "inside-no-expand" file
> +       EOF
> +       ! test_grep "after-heredoc-is-caught" actual
> +'
> +
> +test_expect_success 'sed with << does not start a heredoc' '
> +       sed "s/<< foo/bar/" file &&
> +       ! test_grep "not-inside-sed-heredoc" actual
> +'
> diff --git a/t/lint-style/test-grep-negation-fix.expect b/t/lint-style/test-grep-negation-fix.expect
> new file mode 100644
> index 0000000000..28ecde1073
> --- /dev/null
> +++ b/t/lint-style/test-grep-negation-fix.expect
> @@ -0,0 +1,4 @@
> +test_expect_success 'negated test_grep' '
> +       test_grep ! "pattern" actual &&
> +       test_grep ! -i "insensitive" actual
> +'
> diff --git a/t/lint-style/test-grep-negation-fix.test b/t/lint-style/test-grep-negation-fix.test
> new file mode 100644
> index 0000000000..571c150031
> --- /dev/null
> +++ b/t/lint-style/test-grep-negation-fix.test
> @@ -0,0 +1,4 @@
> +test_expect_success 'negated test_grep' '
> +       ! test_grep "pattern" actual &&
> +       ! test_grep -i "insensitive" actual
> +'
> diff --git a/t/lint-style/test-grep-negation.expect b/t/lint-style/test-grep-negation.expect
> new file mode 100644
> index 0000000000..1fa9e124aa
> --- /dev/null
> +++ b/t/lint-style/test-grep-negation.expect
> @@ -0,0 +1,3 @@
> +lint-style/test-grep-negation.test:2: error: replace '! test_grep' with 'test_grep !': ! test_grep "pattern" actual
> +lint-style/test-grep-negation.test:3: error: replace '! test_grep' with 'test_grep !': ! test_grep -i "insensitive" actual
> +hint: run with --fix to apply the suggested replacements.
> diff --git a/t/lint-style/test-grep-negation.test b/t/lint-style/test-grep-negation.test
> new file mode 100644
> index 0000000000..571c150031
> --- /dev/null
> +++ b/t/lint-style/test-grep-negation.test
> @@ -0,0 +1,4 @@
> +test_expect_success 'negated test_grep' '
> +       ! test_grep "pattern" actual &&
> +       ! test_grep -i "insensitive" actual
> +'
> diff --git a/t/t0031-lockfile-pid.sh b/t/t0031-lockfile-pid.sh
> index 8ef87addf5..e9e2f04049 100755
> --- a/t/t0031-lockfile-pid.sh
> +++ b/t/t0031-lockfile-pid.sh
> @@ -29,7 +29,7 @@ test_expect_success 'PID info not shown by default' '
>                 test_must_fail git add . 2>err &&
>                 # Should not crash, just show normal error without PID
>                 test_grep "Unable to create" err &&
> -               ! test_grep "is held by process" err
> +               test_grep ! "is held by process" err
>         )
>  '
>
> diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
> index 73445782e7..3179b4963e 100755
> --- a/t/t5300-pack-object.sh
> +++ b/t/t5300-pack-object.sh
> @@ -720,7 +720,7 @@ test_expect_success '--name-hash-version=2 and --write-bitmap-index are incompat
>
>         # --stdout option silently removes --write-bitmap-index
>         git pack-objects --stdout --all --name-hash-version=2 --write-bitmap-index >out 2>err &&
> -       ! test_grep "currently, --write-bitmap-index requires --name-hash-version=1" err
> +       test_grep ! "currently, --write-bitmap-index requires --name-hash-version=1" err
>  '
>
>  test_expect_success '--path-walk pack everything' '
> diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
> index fa0d4046f7..9154d9795f 100755
> --- a/t/t5319-multi-pack-index.sh
> +++ b/t/t5319-multi-pack-index.sh
> @@ -1175,7 +1175,7 @@ test_expect_success 'load reverse index when missing .idx, .pack' '
>
>  test_expect_success 'usage shown without sub-command' '
>         test_expect_code 129 git multi-pack-index 2>err &&
> -       ! test_grep "unrecognized subcommand" err
> +       test_grep ! "unrecognized subcommand" err
>  '
>
>  test_expect_success 'complains when run outside of a repository' '
> diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
> index d7f82e1bec..9db4a76f67 100755
> --- a/t/t7900-maintenance.sh
> +++ b/t/t7900-maintenance.sh
> @@ -664,7 +664,7 @@ test_geometric_repack_needed () {
>         true)
>                 test_grep "\[\"git\",\"repack\"," trace2.txt;;
>         false)
> -               ! test_grep "\[\"git\",\"repack\"," trace2.txt;;
> +               test_grep ! "\[\"git\",\"repack\"," trace2.txt;;
>         *)
>                 BUG "invalid parameter: $NEEDED";;
>         esac
> --
> gitgitgadget
>


-- 
D. Ben Knoble

Re: [PATCH 4/6] t: add lint-style.pl with test_grep negation rule

[Michael Montalbo]

On Thu, Jun 4, 2026 at 11:35 AM D. Ben Knoble <ben.knoble@gmail.com> wrote:
>
> Hi Michael,
>
> This sounds like a neat effort!
>
> One drive-by comment…
>
> On Thu, Jun 4, 2026 at 3:46 AM Michael Montalbo via GitGitGadget
> <gitgitgadget@gmail.com> wrote:
> >
> > From: Michael Montalbo <mmontalbo@gmail.com>
> >
> > Add a mechanical lint checker for test scripts, similar in spirit to
> > check-non-portable-shell.pl but focused on test conventions rather
> > than portability.
> >
> > The tool defines LintParser, a subclass of ScriptParser (from the
> > shared lib-shell-parser.pl module).  ScriptParser's
> > parse_cmd() finds test_expect_success blocks and calls check_test()
> > for each body; LintParser overrides check_test() to run lint rules
> > on the parsed commands.  A "# lint-ok" comment suppresses all
> > checks for intentional style violations.
> >
> > The first rule detects '! test_grep' and replaces it with
> > 'test_grep !'.  Shell-level negation suppresses the diagnostic
> > output that test_grep prints on failure; the built-in negation
> > preserves it.
> >
> > Three violations inside test bodies are converted via --fix.  One
> > additional violation in a helper function outside test_expect_success
> > (t7900's test_geometric_repack_needed) is converted manually, since
> > the parser only processes test bodies.
> >
> > Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
> > ---
> >  t/.gitattributes                           |   2 +
> >  t/Makefile                                 |  32 +++-
> >  t/lint-style.pl                            | 200 +++++++++++++++++++++
> >  t/lint-style/heredoc.expect                |   3 +
> >  t/lint-style/heredoc.test                  |  14 ++
> >  t/lint-style/test-grep-negation-fix.expect |   4 +
> >  t/lint-style/test-grep-negation-fix.test   |   4 +
> >  t/lint-style/test-grep-negation.expect     |   3 +
> >  t/lint-style/test-grep-negation.test       |   4 +
> >  t/t0031-lockfile-pid.sh                    |   2 +-
> >  t/t5300-pack-object.sh                     |   2 +-
> >  t/t5319-multi-pack-index.sh                |   2 +-
> >  t/t7900-maintenance.sh                     |   2 +-
> >  13 files changed, 268 insertions(+), 6 deletions(-)
> >  create mode 100755 t/lint-style.pl
> >  create mode 100644 t/lint-style/heredoc.expect
> >  create mode 100644 t/lint-style/heredoc.test
> >  create mode 100644 t/lint-style/test-grep-negation-fix.expect
> >  create mode 100644 t/lint-style/test-grep-negation-fix.test
> >  create mode 100644 t/lint-style/test-grep-negation.expect
> >  create mode 100644 t/lint-style/test-grep-negation.test
> >
> > diff --git a/t/.gitattributes b/t/.gitattributes
> > index 7664c6e027..aea6889d03 100644
> > --- a/t/.gitattributes
> > +++ b/t/.gitattributes
> > @@ -1,5 +1,7 @@
> >  t[0-9][0-9][0-9][0-9]/* -whitespace
> >  /chainlint/*.expect eol=lf -whitespace
> > +/lint-style/*.expect eol=lf -whitespace
> > +/lint-style/*.test eol=lf -whitespace
> >  /t0110/url-* binary
> >  /t3206/* eol=lf
> >  /t3900/*.txt eol=lf
> > diff --git a/t/Makefile b/t/Makefile
> > index 25f923fed9..3a5fa4ce37 100644
> > --- a/t/Makefile
> > +++ b/t/Makefile
> > @@ -46,6 +46,7 @@ TPERF = $(sort $(wildcard perf/p[0-9][0-9][0-9][0-9]-*.sh))
> >  TINTEROP = $(sort $(wildcard interop/i[0-9][0-9][0-9][0-9]-*.sh))
> >  CHAINLINTTESTS = $(sort $(patsubst chainlint/%.test,%,$(wildcard chainlint/*.test)))
> >  CHAINLINT = '$(PERL_PATH_SQ)' chainlint.pl
> > +LINT_STYLE_TESTS = $(sort $(wildcard lint-style/*.test))
> >  UNIT_TEST_SOURCES = $(wildcard unit-tests/t-*.c)
> >  UNIT_TEST_PROGRAMS = $(patsubst unit-tests/%.c,unit-tests/bin/%$(X),$(UNIT_TEST_SOURCES))
> >  UNIT_TEST_PROGRAMS += unit-tests/bin/unit-tests$(X)
> > @@ -139,7 +140,7 @@ check-meson:
> >  test-lint: test-lint-duplicates test-lint-executable \
> >         test-lint-filenames
> >  ifneq ($(PERL_PATH),)
> > -test-lint: test-lint-shell-syntax check-shell-parser
> > +test-lint: test-lint-shell-syntax test-lint-style check-lint-style check-shell-parser
> >  else
> >  GIT_TEST_CHAIN_LINT = 0
> >  endif
> > @@ -162,6 +163,32 @@ test-lint-shell-syntax:
> >
> >  check-shell-parser:
> >         @'$(PERL_PATH_SQ)' check-shell-parser.pl
> > +
> > +test-lint-style:
> > +       @'$(PERL_PATH_SQ)' lint-style.pl $(T) $(THELPERS) $(TPERF)
> > +
> > +check-lint-style:
> > +       @rc=0; for t in $(LINT_STYLE_TESTS); do \
> > +               base=$${t%.test}; \
> > +               case $$base in \
> > +               *-fix) \
> > +                       cp "$$t" "$$t.tmp" && \
> > +                       '$(PERL_PATH_SQ)' lint-style.pl --fix "$$t.tmp" >/dev/null 2>&1; \
> > +                       fix_rc=$$?; \
> > +                       if test $$fix_rc != 0; then \
> > +                               echo "FAIL: $$t (--fix exit code $$fix_rc)"; rc=1; \
> > +                       elif ! diff -u "$$base.expect" "$$t.tmp"; then \
> > +                               echo "FAIL: $$t (--fix output)"; rc=1; \
> > +                       fi; \
> > +                       rm -f "$$t.tmp" ;; \
> > +               *) \
> > +                       if ! '$(PERL_PATH_SQ)' lint-style.pl "$$t" 2>&1 | \
> > +                               diff -u "$$base.expect" -; then \
> > +                               echo "FAIL: $$t"; rc=1; \
> > +                       fi ;; \
> > +               esac; \
> > +       done; test $$rc = 0
> > +
>
> …I wonder if it would be easier to maintain this recipe as a separate
> shell script and have make give LINT_STYLE_TESTS and PERL_PATH (w/o
> SQ? idk) to the script. That's a lot of inline code otherwise!
>

Yeah that's a good call out, will fix in a follow-up. Thank you for
taking a look!

> >  test-lint-filenames:
> >         @# We do *not* pass a glob to ls-files but use grep instead, to catch
> >         @# non-ASCII characters (which are quoted within double-quotes)
> > @@ -188,7 +215,8 @@ perf:
> >
> >  .PHONY: pre-clean $(T) aggregate-results clean valgrind perf \
> >         check-chainlint clean-chainlint test-chainlint \
> > -       check-shell-parser $(UNIT_TESTS)
> > +       check-shell-parser \
> > +       check-lint-style test-lint-style $(UNIT_TESTS)
> >
> >  .PHONY: libgit-sys-test libgit-rs-test
> >  libgit-sys-test:
> > diff --git a/t/lint-style.pl b/t/lint-style.pl
> > new file mode 100755
> > index 0000000000..9268577f9b
> > --- /dev/null
> > +++ b/t/lint-style.pl
> > @@ -0,0 +1,200 @@
> > +#!/usr/bin/perl
> > +
> > +# Check test scripts for style violations that can be detected
> > +# mechanically, such as using bare 'grep' where test_grep should
> > +# be used.  Use --fix to automatically apply suggested replacements.
> > +#
> > +# Detection uses parsed tokens from the shared shell parser for
> > +# correct handling of heredocs, $(...), pipes, and quoting.
> > +# Fixes modify the original file text to preserve formatting.
> > +
> > +use strict;
> > +use warnings;
> > +use File::Basename;
> > +# Force LF output so check-lint-style's diff against the
> > +# pre-committed .expect files works on Windows.
> > +binmode(STDOUT, ':unix');
> > +binmode(STDERR, ':unix');
> > +
> > +my $fix_mode = 0;
> > +if (@ARGV && $ARGV[0] eq '--fix') {
> > +       $fix_mode = 1;
> > +       shift @ARGV;
> > +}
> > +
> > +# Load the shared shell parser (Lexer, ShellParser, ScriptParser).
> > +my $_lib = dirname($0) . "/lib-shell-parser.pl";
> > +$_lib = "./$_lib" unless $_lib =~ m{^/};
> > +do $_lib or die "$0: failed to load $_lib: $@$!\n";
> > +
> > +# LintParser is a subclass of ScriptParser which runs lint rules
> > +# on each test body.  Per-file state (file name, raw lines, dirty
> > +# flag) is stored on the instance before calling parse().
> > +#
> > +# Subroutines defined below (parse_commands, check_test_grep_negation,
> > +# etc.) are in package main and called with the main:: prefix.
> > +# File-scoped lexicals ($fix_mode, $has_fixable, etc.) are visible
> > +# across packages since 'package' does not introduce a new scope.
> > +package LintParser;
> > +our @ISA = ('ScriptParser');
> > +
> > +package main;
> > +
> > +my $exit_code = 0;
> > +my $has_fixable = 0;
> > +
> > +sub err {
> > +       my ($file, $lineno, $line, $msg, %opts) = @_;
> > +       $line =~ s/^\s+//;
> > +       $line =~ s/\s+$//;
> > +       $line =~ s/\s+/ /g;
> > +       my $prefix = ($fix_mode && $opts{fixable}) ? 'fixed' : 'error';
> > +       print "$file:$lineno: $prefix: $msg: $line\n";
> > +       $exit_code = 1 unless $fix_mode && $opts{fixable};
> > +}
> > +
> > +# Report a lint violation found by a rule.  In --fix mode, apply
> > +# the regex substitution on the raw line and report success.
> > +# Otherwise just report.  Returns 1 if the line was modified.
> > +sub report_violation {
> > +       my ($file, $cmd, $line_ref, $match, $fix, $from) = @_;
> > +       my $lineno = $cmd->{lineno};
> > +       my $display = join(' ', @{$cmd->{tokens}});
> > +       $has_fixable++;  # count for the "--fix" hint
> > +       if ($fix_mode) {
> > +               if ($$line_ref =~ s/$match/$fix/) {
> > +                       err $file, $lineno, $display,
> > +                               "replace '$from' with '$fix'",
> > +                               fixable => 1;
> > +                       return 1;
> > +               }
> > +               err $file, $lineno, $display,
> > +                       "replace '$from' with '$fix' (could not auto-fix)";
> > +       } else {
> > +               err $file, $lineno, $display,
> > +                       "replace '$from' with '$fix'";
> > +       }
> > +       return 0;
> > +}
> > +
> > +# Split a token stream into commands at &&, ||, ;;, and \n.
> > +sub parse_commands {
> > +       my ($content) = @_;
> > +       my $parser = ShellParser->new(\$content);
> > +       my @all_tokens = $parser->parse();
> > +
> > +       my @commands;
> > +       my @current;
> > +       my $lineno = 1;
> > +
> > +       for (my $ti = 0; $ti < @all_tokens; $ti++) {
> > +               my $text = $all_tokens[$ti]->[0];
> > +               if ($text =~ /^(?:&&|\|\||;;|\n)$/) {
> > +                       if (@current) {
> > +                               push @commands, {
> > +                                       tokens => [@current],
> > +                                       lineno => $lineno,
> > +                               };
> > +                               @current = ();
> > +                       }
> > +               } else {
> > +                       $lineno = $all_tokens[$ti]->[3]
> > +                               if !@current && defined $all_tokens[$ti]->[3];
> > +                       push @current, $text;
> > +               }
> > +       }
> > +       if (@current) {
> > +               push @commands, {
> > +                       tokens => [@current],
> > +                       lineno => $lineno,
> > +               };
> > +       }
> > +       return @commands;
> > +}
> > +
> > +# --- Rule: '! test_grep' should be 'test_grep !' ---
> > +# Shell-level negation suppresses test_grep's diagnostic output
> > +# on failure.  Built-in negation preserves it.
> > +sub check_test_grep_negation {
> > +       my ($cmd, $file, $line_ref) = @_;
> > +       my @tokens = @{$cmd->{tokens}};
> > +       return unless @tokens >= 2 && $tokens[0] eq '!' && $tokens[1] eq 'test_grep';
> > +
> > +       return report_violation($file, $cmd, $line_ref,
> > +               qr/!\s*test_grep/, 'test_grep !', '! test_grep');
> > +}
> > +
> > +# Map parsed commands back to raw file lines for --fix.
> > +# Detection uses parsed tokens (correct handling of quoting,
> > +# heredocs, pipes) but fixes must modify the original text
> > +# to preserve formatting.
> > +package LintParser;
> > +
> > +sub check_test {
> > +       # Called by ScriptParser::parse_cmd for each test_expect_success
> > +       # or test_expect_failure block.
> > +       my $self = shift @_;
> > +       my $title = ScriptParser::unwrap(shift @_);
> > +
> > +       # Two test body formats:
> > +       #   Quoted:  test_expect_success 'title' '..body..'
> > +       #   Heredoc: test_expect_success 'title' - <<\EOF
> > +       #              ..body..
> > +       #            EOF
> > +       # For quoted, the body token is the quoted string.
> > +       # For heredoc, the body token is '-' and the actual
> > +       # code arrives as the next argument from the Lexer.
> > +       my $body_token = shift @_;
> > +       my $lineno_base = $body_token->[3] || 1;
> > +       my $body = ScriptParser::unwrap($body_token);
> > +
> > +       if ($body eq '-') {
> > +               my $herebody = shift @_;
> > +               if ($herebody) {
> > +                       $body = $herebody->{content};
> > +                       $lineno_base = $herebody->{start_line} || 1;
> > +               }
> > +       }
> > +       return unless $body;
> > +
> > +       # Map each command back to its file line number.
> > +       # $lineno_base is where the body starts in the file;
> > +       # $cmd->{lineno} is relative to the body (starting at 1).
> > +       my $raw_lines = $self->{raw_lines};
> > +       for my $cmd (main::parse_commands($body)) {
> > +               my $ln = ($cmd->{lineno} || 0) + $lineno_base - 1;
> > +               $cmd->{lineno} = $ln;
> > +               next unless $ln >= 1 && $ln <= @$raw_lines;
> > +               next if $raw_lines->[$ln - 1] =~ /#.*lint-ok/;
> > +
> > +               if (main::check_test_grep_negation($cmd, $self->{file}, \$raw_lines->[$ln - 1])) {
> > +                       $self->{dirty} = 1;
> > +               }
> > +       }
> > +}
> > +
> > +package main;
> > +
> > +for my $file (@ARGV) {
> > +       # :unix:crlf strips \r on Windows (same as chainlint.pl)
> > +       open(my $fh, '<:unix:crlf', $file) or die "$0: $file: $!\n";
> > +       my @raw_lines = <$fh>;
> > +       close $fh;
> > +
> > +       my $parser = LintParser->new(\join('', @raw_lines));
> > +       $parser->{file} = $file;
> > +       $parser->{raw_lines} = \@raw_lines;
> > +       $parser->{dirty} = 0;
> > +       $parser->parse();
> > +
> > +       if ($fix_mode && $parser->{dirty}) {
> > +               open(my $out, '>', $file) or die "$0: $file: $!\n";
> > +               print $out @{$parser->{raw_lines}};
> > +               close $out;
> > +       }
> > +}
> > +
> > +if ($has_fixable && !$fix_mode) {
> > +       print "hint: run with --fix to apply the suggested replacements.\n";
> > +}
> > +exit $exit_code;
> > diff --git a/t/lint-style/heredoc.expect b/t/lint-style/heredoc.expect
> > new file mode 100644
> > index 0000000000..7ff6d4a52d
> > --- /dev/null
> > +++ b/t/lint-style/heredoc.expect
> > @@ -0,0 +1,3 @@
> > +lint-style/heredoc.test:8: error: replace '! test_grep' with 'test_grep !': ! test_grep "after-heredoc-is-caught" actual
> > +lint-style/heredoc.test:13: error: replace '! test_grep' with 'test_grep !': ! test_grep "not-inside-sed-heredoc" actual
> > +hint: run with --fix to apply the suggested replacements.
> > diff --git a/t/lint-style/heredoc.test b/t/lint-style/heredoc.test
> > new file mode 100644
> > index 0000000000..4c05831cfb
> > --- /dev/null
> > +++ b/t/lint-style/heredoc.test
> > @@ -0,0 +1,14 @@
> > +test_expect_success 'greps inside heredocs are skipped' '
> > +       cat <<-EOF &&
> > +       grep "inside-strip-tabs" file
> > +       EOF
> > +       cat <<-\EOF &&
> > +       grep "inside-no-expand" file
> > +       EOF
> > +       ! test_grep "after-heredoc-is-caught" actual
> > +'
> > +
> > +test_expect_success 'sed with << does not start a heredoc' '
> > +       sed "s/<< foo/bar/" file &&
> > +       ! test_grep "not-inside-sed-heredoc" actual
> > +'
> > diff --git a/t/lint-style/test-grep-negation-fix.expect b/t/lint-style/test-grep-negation-fix.expect
> > new file mode 100644
> > index 0000000000..28ecde1073
> > --- /dev/null
> > +++ b/t/lint-style/test-grep-negation-fix.expect
> > @@ -0,0 +1,4 @@
> > +test_expect_success 'negated test_grep' '
> > +       test_grep ! "pattern" actual &&
> > +       test_grep ! -i "insensitive" actual
> > +'
> > diff --git a/t/lint-style/test-grep-negation-fix.test b/t/lint-style/test-grep-negation-fix.test
> > new file mode 100644
> > index 0000000000..571c150031
> > --- /dev/null
> > +++ b/t/lint-style/test-grep-negation-fix.test
> > @@ -0,0 +1,4 @@
> > +test_expect_success 'negated test_grep' '
> > +       ! test_grep "pattern" actual &&
> > +       ! test_grep -i "insensitive" actual
> > +'
> > diff --git a/t/lint-style/test-grep-negation.expect b/t/lint-style/test-grep-negation.expect
> > new file mode 100644
> > index 0000000000..1fa9e124aa
> > --- /dev/null
> > +++ b/t/lint-style/test-grep-negation.expect
> > @@ -0,0 +1,3 @@
> > +lint-style/test-grep-negation.test:2: error: replace '! test_grep' with 'test_grep !': ! test_grep "pattern" actual
> > +lint-style/test-grep-negation.test:3: error: replace '! test_grep' with 'test_grep !': ! test_grep -i "insensitive" actual
> > +hint: run with --fix to apply the suggested replacements.
> > diff --git a/t/lint-style/test-grep-negation.test b/t/lint-style/test-grep-negation.test
> > new file mode 100644
> > index 0000000000..571c150031
> > --- /dev/null
> > +++ b/t/lint-style/test-grep-negation.test
> > @@ -0,0 +1,4 @@
> > +test_expect_success 'negated test_grep' '
> > +       ! test_grep "pattern" actual &&
> > +       ! test_grep -i "insensitive" actual
> > +'
> > diff --git a/t/t0031-lockfile-pid.sh b/t/t0031-lockfile-pid.sh
> > index 8ef87addf5..e9e2f04049 100755
> > --- a/t/t0031-lockfile-pid.sh
> > +++ b/t/t0031-lockfile-pid.sh
> > @@ -29,7 +29,7 @@ test_expect_success 'PID info not shown by default' '
> >                 test_must_fail git add . 2>err &&
> >                 # Should not crash, just show normal error without PID
> >                 test_grep "Unable to create" err &&
> > -               ! test_grep "is held by process" err
> > +               test_grep ! "is held by process" err
> >         )
> >  '
> >
> > diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
> > index 73445782e7..3179b4963e 100755
> > --- a/t/t5300-pack-object.sh
> > +++ b/t/t5300-pack-object.sh
> > @@ -720,7 +720,7 @@ test_expect_success '--name-hash-version=2 and --write-bitmap-index are incompat
> >
> >         # --stdout option silently removes --write-bitmap-index
> >         git pack-objects --stdout --all --name-hash-version=2 --write-bitmap-index >out 2>err &&
> > -       ! test_grep "currently, --write-bitmap-index requires --name-hash-version=1" err
> > +       test_grep ! "currently, --write-bitmap-index requires --name-hash-version=1" err
> >  '
> >
> >  test_expect_success '--path-walk pack everything' '
> > diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
> > index fa0d4046f7..9154d9795f 100755
> > --- a/t/t5319-multi-pack-index.sh
> > +++ b/t/t5319-multi-pack-index.sh
> > @@ -1175,7 +1175,7 @@ test_expect_success 'load reverse index when missing .idx, .pack' '
> >
> >  test_expect_success 'usage shown without sub-command' '
> >         test_expect_code 129 git multi-pack-index 2>err &&
> > -       ! test_grep "unrecognized subcommand" err
> > +       test_grep ! "unrecognized subcommand" err
> >  '
> >
> >  test_expect_success 'complains when run outside of a repository' '
> > diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
> > index d7f82e1bec..9db4a76f67 100755
> > --- a/t/t7900-maintenance.sh
> > +++ b/t/t7900-maintenance.sh
> > @@ -664,7 +664,7 @@ test_geometric_repack_needed () {
> >         true)
> >                 test_grep "\[\"git\",\"repack\"," trace2.txt;;
> >         false)
> > -               ! test_grep "\[\"git\",\"repack\"," trace2.txt;;
> > +               test_grep ! "\[\"git\",\"repack\"," trace2.txt;;
> >         *)
> >                 BUG "invalid parameter: $NEEDED";;
> >         esac
> > --
> > gitgitgadget
> >
>
>
> --
> D. Ben Knoble

[PATCH 5/6] t: fix grep assertions missing file arguments

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

Three grep assertions were missing their file arguments, causing
them to read from empty stdin instead of the intended file:

- t2402: '! grep ...' should read from 'out', matching the
  grep on the preceding line.
- t7507: the closing quote is in the wrong place, making the
  entire 'diff --git actual' a single pattern with no file
  argument instead of pattern 'diff --git' and file 'actual'.
- t7700: '! grep ...' should read from 'packlist', matching
  the redirect on the preceding line.

Without file arguments these greps always succeed (empty stdin
matches nothing), so the assertions were not actually checking
anything.  All three tests pass with the corrected file arguments,
confirming the intended behavior is sound.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 t/t2402-worktree-list.sh  | 2 +-
 t/t7507-commit-verbose.sh | 2 +-
 t/t7700-repack.sh         | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/t/t2402-worktree-list.sh b/t/t2402-worktree-list.sh
index e0c6abd2f5..93f92e854a 100755
--- a/t/t2402-worktree-list.sh
+++ b/t/t2402-worktree-list.sh
@@ -144,7 +144,7 @@ test_expect_success '"list" all worktrees with prunable annotation' '
 	rm -rf prunable &&
 	git worktree list >out &&
 	grep "/prunable  *[0-9a-f].* prunable$" out &&
-	! grep "/unprunable  *[0-9a-f].* prunable$"
+	! grep "/unprunable  *[0-9a-f].* prunable$" out
 '
 
 test_expect_success '"list" all worktrees --porcelain with prunable' '
diff --git a/t/t7507-commit-verbose.sh b/t/t7507-commit-verbose.sh
index b53d71c086..acdb6b1455 100755
--- a/t/t7507-commit-verbose.sh
+++ b/t/t7507-commit-verbose.sh
@@ -163,7 +163,7 @@ done
 
 test_expect_success "status ignores commit.verbose=true" '
 	git -c commit.verbose=true status >actual &&
-	! grep "^diff --git actual"
+	! grep "^diff --git" actual
 '
 
 test_done
diff --git a/t/t7700-repack.sh b/t/t7700-repack.sh
index 63ef63fc50..c6ff3aed30 100755
--- a/t/t7700-repack.sh
+++ b/t/t7700-repack.sh
@@ -194,7 +194,7 @@ test_expect_success 'local packed unreachable obs that exist in alternate ODB ar
 	rm -f .git/objects/pack/* &&
 	mv pack-* .git/objects/pack/ &&
 	git verify-pack -v -- .git/objects/pack/*.idx >packlist &&
-	! grep "^$coid " &&
+	! grep "^$coid " packlist &&
 	echo >.git/objects/info/alternates &&
 	test_must_fail git show $coid
 '
-- 
gitgitgadget

[PATCH 6/6] t: lint and convert grep assertions to test_grep

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

Extend lint-style.pl with a rule that detects bare 'grep' used as a
test assertion and converts it to test_grep.  test_grep prints the
file contents on failure, making test debugging significantly easier.

parse_commands() is extended to split at shell structural tokens
({, }, (, ), |) and keywords (if, then, for, etc.), and each
command gains a token_pos index so that rules can scan backward and
forward in the token stream for context.

Three new functions implement the grep-assertion rule:

 - is_filter_context() scans the surrounding tokens for pipes,
   control-flow keywords (if/elif/while/until), for-in value
   lists, and brace groups with output redirects.

 - is_grep_assertion() classifies a grep command: convertible
   assertion (pattern and file present), filter (not an assertion),
   or missing file argument (flagged as a likely bug).

 - check_bare_grep() ties them together and calls
   report_violation() with the appropriate fix.

The --fix mode handles:
 - Replacing 'grep' with 'test_grep'
 - Moving negation from '! grep' to 'test_grep !'
 - Stripping the -q flag (test_grep inherently checks match status)

Five files require '# lint-ok' annotations for intentional grep
usage that cannot be mechanically converted: t1400 (packed-refs
may not exist on reftable), t3901 (piped stdin via case block),
t6437 (glob argument breaks test_grep's test -f check), t7450
(file may not exist after failed MINGW clone), and t7527 ($?
capture on the next line).

The test-lint-style scope is extended to include sourced test
fragments in subdirectories (t5411/*.sh and similar) via a new
TSOURCED variable.

Run '--fix' to convert all ~2800 grep assertions across ~340 files
in the test suite.  test-lib-functions.sh and lib-rebase.sh are
excluded from linting since they implement test infrastructure
rather than test assertions.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 t/Makefile                                   |   4 +-
 t/for-each-ref-tests.sh                      |  12 +-
 t/lib-bitmap.sh                              |  12 +-
 t/lib-bundle-uri-protocol.sh                 |  26 +-
 t/lib-httpd.sh                               |   2 +-
 t/lint-style.pl                              | 289 ++++++++++++++--
 t/lint-style/grep-assert.expect              |  13 +
 t/lint-style/grep-assert.test                |  24 ++
 t/lint-style/grep-fix.expect                 |  16 +
 t/lint-style/grep-fix.test                   |  16 +
 t/lint-style/grep-missing-file.expect        |   4 +
 t/lint-style/grep-missing-file.test          |   6 +
 t/lint-style/grep-negated.expect             |   5 +
 t/lint-style/grep-negated.test               |   9 +
 t/lint-style/grep-not-assert.expect          |   0
 t/lint-style/grep-not-assert.test            |  43 +++
 t/pack-refs-tests.sh                         |   2 +-
 t/show-ref-exists-tests.sh                   |   2 +-
 t/t0000-basic.sh                             |  16 +-
 t/t0001-init.sh                              |  18 +-
 t/t0008-ignores.sh                           |   8 +-
 t/t0009-git-dir-validation.sh                |   6 +-
 t/t0012-help.sh                              |   4 +-
 t/t0013-sha1dc.sh                            |   2 +-
 t/t0017-env-helper.sh                        |   4 +-
 t/t0021-conversion.sh                        |  18 +-
 t/t0029-core-unsetenvvars.sh                 |   4 +-
 t/t0030-stripspace.sh                        |   4 +-
 t/t0040-parse-options.sh                     |  52 +--
 t/t0041-usage.sh                             |   2 +-
 t/t0052-simple-ipc.sh                        |  10 +-
 t/t0061-run-command.sh                       |   2 +-
 t/t0066-dir-iterator.sh                      |   2 +-
 t/t0068-for-each-repo.sh                     |  16 +-
 t/t0070-fundamental.sh                       |   6 +-
 t/t0081-find-pack.sh                         |  12 +-
 t/t0091-bugreport.sh                         |  18 +-
 t/t0092-diagnose.sh                          |  12 +-
 t/t0100-previous.sh                          |   2 +-
 t/t0200-gettext-basic.sh                     |  14 +-
 t/t0203-gettext-setlocale-sanity.sh          |   4 +-
 t/t0204-gettext-reencode-sanity.sh           |   8 +-
 t/t0210-trace2-normal.sh                     |   6 +-
 t/t0211-trace2-perf.sh                       |  80 ++---
 t/t0212-trace2-event.sh                      |   8 +-
 t/t0300-credentials.sh                       |   4 +-
 t/t0410-partial-clone.sh                     |  82 ++---
 t/t0450-txt-doc-vs-help.sh                   |   2 +-
 t/t0500-progress-display.sh                  |  18 +-
 t/t0610-reftable-basics.sh                   |   8 +-
 t/t1004-read-tree-m-u-wf.sh                  |   8 +-
 t/t1006-cat-file.sh                          |  18 +-
 t/t1007-hash-object.sh                       |   8 +-
 t/t1011-read-tree-sparse-checkout.sh         |  10 +-
 t/t1050-large.sh                             |   6 +-
 t/t1091-sparse-checkout-builtin.sh           |  24 +-
 t/t1092-sparse-checkout-compatibility.sh     |  44 +--
 t/t1300-config.sh                            |  16 +-
 t/t1305-config-include.sh                    |   2 +-
 t/t1308-config-set.sh                        |   6 +-
 t/t1400-update-ref.sh                        | 170 ++++-----
 t/t1403-show-ref.sh                          |  18 +-
 t/t1410-reflog.sh                            |   4 +-
 t/t1415-worktree-refs.sh                     |   4 +-
 t/t1430-bad-ref-name.sh                      |  56 +--
 t/t1450-fsck.sh                              |  12 +-
 t/t1451-fsck-buffer.sh                       |   6 +-
 t/t1460-refs-migrate.sh                      |   2 +-
 t/t1500-rev-parse.sh                         |   6 +-
 t/t1502-rev-parse-parseopt.sh                |   2 +-
 t/t1503-rev-parse-verify.sh                  |  10 +-
 t/t1510-repo-setup.sh                        |  10 +-
 t/t1512-rev-parse-disambiguation.sh          |   4 +-
 t/t1515-rev-parse-outside-repo.sh            |   2 +-
 t/t1800-hook.sh                              |  18 +-
 t/t2004-checkout-cache-temp.sh               |   4 +-
 t/t2019-checkout-ambiguous-ref.sh            |   4 +-
 t/t2024-checkout-dwim.sh                     |   8 +-
 t/t2030-unresolve-info.sh                    |   6 +-
 t/t2060-switch.sh                            |   6 +-
 t/t2070-restore.sh                           |   2 +-
 t/t2080-parallel-checkout-basics.sh          |  14 +-
 t/t2081-parallel-checkout-collisions.sh      |  24 +-
 t/t2082-parallel-checkout-attributes.sh      |  12 +-
 t/t2103-update-index-ignore-missing.sh       |   6 +-
 t/t2200-add-update.sh                        |   2 +-
 t/t2203-add-intent.sh                        |   6 +-
 t/t2400-worktree-add.sh                      |  24 +-
 t/t2402-worktree-list.sh                     |  16 +-
 t/t2403-worktree-move.sh                     |   6 +-
 t/t2405-worktree-submodule.sh                |   6 +-
 t/t2407-worktree-heads.sh                    |  26 +-
 t/t2500-untracked-overwriting.sh             |   8 +-
 t/t2501-cwd-empty.sh                         |   4 +-
 t/t3001-ls-files-others-exclude.sh           |   6 +-
 t/t3007-ls-files-recurse-submodules.sh       |   6 +-
 t/t3200-branch.sh                            |  12 +-
 t/t3202-show-branch.sh                       |  10 +-
 t/t3203-branch-output.sh                     |   4 +-
 t/t3206-range-diff.sh                        |  78 ++---
 t/t3207-branch-submodule.sh                  |   4 +-
 t/t3301-notes.sh                             |  32 +-
 t/t3310-notes-merge-manual-resolve.sh        |  16 +-
 t/t3320-notes-merge-worktrees.sh             |   2 +-
 t/t3400-rebase.sh                            |  16 +-
 t/t3402-rebase-merge.sh                      |  16 +-
 t/t3404-rebase-interactive.sh                |  72 ++--
 t/t3406-rebase-message.sh                    |   6 +-
 t/t3415-rebase-autosquash.sh                 |  10 +-
 t/t3416-rebase-onto-threedots.sh             |   4 +-
 t/t3418-rebase-continue.sh                   |  10 +-
 t/t3420-rebase-autostash.sh                  |  25 +-
 t/t3422-rebase-incompatible-options.sh       |   4 +-
 t/t3429-rebase-edit-todo.sh                  |   2 +-
 t/t3430-rebase-merges.sh                     |  32 +-
 t/t3500-cherry.sh                            |   4 +-
 t/t3501-revert-cherry-pick.sh                |   6 +-
 t/t3504-cherry-pick-rerere.sh                |   6 +-
 t/t3510-cherry-pick-sequence.sh              |  24 +-
 t/t3602-rm-sparse-checkout.sh                |   4 +-
 t/t3705-add-sparse-checkout.sh               |  10 +-
 t/t3800-mktag.sh                             |   4 +-
 t/t3901-i18n-patch.sh                        |  20 +-
 t/t3903-stash.sh                             |  28 +-
 t/t3904-stash-patch.sh                       |   4 +-
 t/t3908-stash-in-worktree.sh                 |   2 +-
 t/t4000-diff-format.sh                       |   2 +-
 t/t4001-diff-rename.sh                       |   4 +-
 t/t4011-diff-symlink.sh                      |   2 +-
 t/t4013-diff-various.sh                      |   2 +-
 t/t4014-format-patch.sh                      | 344 +++++++++----------
 t/t4015-diff-whitespace.sh                   |  16 +-
 t/t4017-diff-retval.sh                       |   2 +-
 t/t4018-diff-funcname.sh                     |   2 +-
 t/t4019-diff-wserror.sh                      |   8 +-
 t/t4020-diff-external.sh                     |  18 +-
 t/t4021-format-patch-numbered.sh             |   4 +-
 t/t4022-diff-rewrite.sh                      |  14 +-
 t/t4028-format-patch-mime-headers.sh         |   6 +-
 t/t4031-diff-rewrite-binary.sh               |  18 +-
 t/t4033-diff-patience.sh                     |   2 +-
 t/t4036-format-patch-signer-mime.sh          |   6 +-
 t/t4038-diff-combined.sh                     |   6 +-
 t/t4051-diff-function-context.sh             |  38 +-
 t/t4053-diff-no-index.sh                     |   4 +-
 t/t4063-diff-blobs.sh                        |   2 +-
 t/t4065-diff-anchored.sh                     |  26 +-
 t/t4067-diff-partial-clone.sh                |  12 +-
 t/t4073-diff-stat-name-width.sh              |  24 +-
 t/t4103-apply-binary.sh                      |   2 +-
 t/t4120-apply-popt.sh                        |   2 +-
 t/t4124-apply-ws-rule.sh                     |  10 +-
 t/t4128-apply-root.sh                        |   2 +-
 t/t4140-apply-ita.sh                         |   4 +-
 t/t4141-apply-too-large.sh                   |   2 +-
 t/t4150-am.sh                                |  48 +--
 t/t4200-rerere.sh                            |   6 +-
 t/t4201-shortlog.sh                          |   2 +-
 t/t4202-log.sh                               |  84 ++---
 t/t4204-patch-id.sh                          |   2 +-
 t/t4205-log-pretty-formats.sh                |   2 +-
 t/t4209-log-pickaxe.sh                       |  10 +-
 t/t4211-line-log.sh                          |  72 ++--
 t/t4216-log-bloom.sh                         |  18 +-
 t/t4252-am-options.sh                        |  22 +-
 t/t4254-am-corrupt.sh                        |   6 +-
 t/t4258-am-quoted-cr.sh                      |   2 +-
 t/t4301-merge-tree-write-tree.sh             |  18 +-
 t/t5000-tar-tree.sh                          |  10 +-
 t/t5004-archive-corner-cases.sh              |   2 +-
 t/t5100-mailinfo.sh                          |   2 +-
 t/t5150-request-pull.sh                      |  18 +-
 t/t5300-pack-object.sh                       |  20 +-
 t/t5302-pack-index.sh                        |   6 +-
 t/t5304-prune.sh                             |   8 +-
 t/t5310-pack-bitmaps.sh                      |  14 +-
 t/t5317-pack-objects-filter-objects.sh       |  12 +-
 t/t5318-commit-graph.sh                      |   8 +-
 t/t5319-multi-pack-index.sh                  |  14 +-
 t/t5324-split-commit-graph.sh                |  10 +-
 t/t5325-reverse-index.sh                     |   2 +-
 t/t5326-multi-pack-bitmaps.sh                |  28 +-
 t/t5328-commit-graph-64bit-time.sh           |   2 +-
 t/t5329-pack-objects-cruft.sh                |   8 +-
 t/t5334-incremental-multi-pack-index.sh      |   2 +-
 t/t5335-compact-multi-pack-index.sh          |   4 +-
 t/t5351-unpack-large-objects.sh              |   2 +-
 t/t5402-post-merge-hook.sh                   |   4 +-
 t/t5403-post-checkout-hook.sh                |   2 +-
 t/t5404-tracking-branches.sh                 |   2 +-
 t/t5406-remote-rejects.sh                    |   2 +-
 t/t5407-post-rewrite-hook.sh                 |   8 +-
 t/t5409-colorize-remote-messages.sh          |  36 +-
 t/t5411/test-0013-bad-protocol.sh            |  14 +-
 t/t5411/test-0014-bad-protocol--porcelain.sh |  14 +-
 t/t5500-fetch-pack.sh                        |  38 +-
 t/t5504-fetch-receive-strict.sh              |  14 +-
 t/t5505-remote.sh                            |  20 +-
 t/t5510-fetch.sh                             |  10 +-
 t/t5512-ls-remote.sh                         |   8 +-
 t/t5514-fetch-multiple.sh                    |   2 +-
 t/t5516-fetch-push.sh                        |  20 +-
 t/t5520-pull.sh                              |   4 +-
 t/t5524-pull-msg.sh                          |   6 +-
 t/t5526-fetch-submodules.sh                  |  16 +-
 t/t5529-push-errors.sh                       |   4 +-
 t/t5530-upload-pack-error.sh                 |  18 +-
 t/t5531-deep-submodule-push.sh               |   2 +-
 t/t5532-fetch-proxy.sh                       |   2 +-
 t/t5533-push-cas.sh                          |  12 +-
 t/t5534-push-signed.sh                       |  22 +-
 t/t5537-fetch-shallow.sh                     |   2 +-
 t/t5538-push-shallow.sh                      |   2 +-
 t/t5539-fetch-http-shallow.sh                |   4 +-
 t/t5541-http-push-smart.sh                   |  32 +-
 t/t5544-pack-objects-hook.sh                 |  12 +-
 t/t5550-http-fetch-dumb.sh                   |   4 +-
 t/t5551-http-fetch-smart.sh                  |  46 +--
 t/t5552-skipping-fetch-negotiator.sh         |   6 +-
 t/t5554-noop-fetch-negotiator.sh             |   4 +-
 t/t5557-http-get.sh                          |   2 +-
 t/t5558-clone-bundle-uri.sh                  |  38 +-
 t/t5562-http-backend-content-length.sh       |   2 +-
 t/t5564-http-proxy.sh                        |  10 +-
 t/t5581-http-curl-verbose.sh                 |   2 +-
 t/t5583-push-branches.sh                     |   8 +-
 t/t5601-clone.sh                             |  28 +-
 t/t5604-clone-reference.sh                   |   8 +-
 t/t5605-clone-local.sh                       |   2 +-
 t/t5606-clone-options.sh                     |   6 +-
 t/t5612-clone-refspec.sh                     |   2 +-
 t/t5616-partial-clone.sh                     |  60 ++--
 t/t5619-clone-local-ambiguous-transport.sh   |   2 +-
 t/t5620-backfill.sh                          |  12 +-
 t/t5700-protocol-v1.sh                       |  46 +--
 t/t5701-git-serve.sh                         |  14 +-
 t/t5702-protocol-v2.sh                       | 152 ++++----
 t/t5703-upload-pack-ref-in-want.sh           |  22 +-
 t/t5705-session-id-in-capabilities.sh        |  12 +-
 t/t5750-bundle-uri-parse.sh                  |   8 +-
 t/t5801-remote-helpers.sh                    |   4 +-
 t/t5810-proto-disable-local.sh               |   2 +-
 t/t5813-proto-disable-ssh.sh                 |   4 +-
 t/t6000-rev-list-misc.sh                     |  26 +-
 t/t6005-rev-list-count.sh                    |   8 +-
 t/t6006-rev-list-format.sh                   |   4 +-
 t/t6009-rev-list-parent.sh                   |   4 +-
 t/t6020-bundle-misc.sh                       |  12 +-
 t/t6022-rev-list-missing.sh                  |   4 +-
 t/t6030-bisect-porcelain.sh                  | 150 ++++----
 t/t6040-tracking-info.sh                     |   2 +-
 t/t6112-rev-list-filters-objects.sh          |  24 +-
 t/t6115-rev-list-du.sh                       |   4 +-
 t/t6120-describe.sh                          |  14 +-
 t/t6200-fmt-merge-msg.sh                     |  82 ++---
 t/t6402-merge-rename.sh                      |   4 +-
 t/t6403-merge-file.sh                        |   6 +-
 t/t6404-recursive-merge.sh                   |   2 +-
 t/t6406-merge-attr.sh                        |  20 +-
 t/t6417-merge-ours-theirs.sh                 |  30 +-
 t/t6418-merge-text-auto.sh                   |   2 +-
 t/t6422-merge-rename-corner-cases.sh         |   8 +-
 t/t6423-merge-rename-directories.sh          |  72 ++--
 t/t6424-merge-unrelated-index-changes.sh     |   6 +-
 t/t6427-diff3-conflict-markers.sh            |  10 +-
 t/t6432-merge-recursive-space-options.sh     |   4 +-
 t/t6436-merge-overwrite.sh                   |   6 +-
 t/t6437-submodule-merge.sh                   |  12 +-
 t/t6500-gc.sh                                |   8 +-
 t/t6600-test-reach.sh                        |   4 +-
 t/t7001-mv.sh                                |  16 +-
 t/t7002-mv-sparse-checkout.sh                |  38 +-
 t/t7003-filter-branch.sh                     |  16 +-
 t/t7004-tag.sh                               |   2 +-
 t/t7006-pager.sh                             |  16 +-
 t/t7012-skip-worktree-writing.sh             |   6 +-
 t/t7030-verify-tag.sh                        |  52 +--
 t/t7031-verify-tag-signed-ssh.sh             |  46 +--
 t/t7102-reset.sh                             |   2 +-
 t/t7110-reset-merge.sh                       |  40 +--
 t/t7201-co.sh                                |   6 +-
 t/t7300-clean.sh                             |   2 +-
 t/t7301-clean-interactive.sh                 |   2 +-
 t/t7400-submodule-basic.sh                   |  32 +-
 t/t7402-submodule-rebase.sh                  |   2 +-
 t/t7406-submodule-update.sh                  |  26 +-
 t/t7416-submodule-dash-url.sh                |  20 +-
 t/t7417-submodule-path-url.sh                |   2 +-
 t/t7450-bad-git-dotfiles.sh                  |  14 +-
 t/t7501-commit-basic-functionality.sh        |  14 +-
 t/t7502-commit-porcelain.sh                  |   2 +-
 t/t7507-commit-verbose.sh                    |   6 +-
 t/t7508-status.sh                            |   6 +-
 t/t7510-signed-commit.sh                     |  68 ++--
 t/t7516-commit-races.sh                      |   4 +-
 t/t7519-status-fsmonitor.sh                  |  14 +-
 t/t7527-builtin-fsmonitor.sh                 |  84 ++---
 t/t7528-signed-commit-ssh.sh                 |  68 ++--
 t/t7600-merge.sh                             |  10 +-
 t/t7603-merge-reduce-heads.sh                |  20 +-
 t/t7606-merge-custom.sh                      |   2 +-
 t/t7607-merge-state.sh                       |   4 +-
 t/t7610-mergetool.sh                         |  18 +-
 t/t7700-repack.sh                            |  14 +-
 t/t7703-repack-geometric.sh                  |   4 +-
 t/t7704-repack-cruft.sh                      |  12 +-
 t/t7800-difftool.sh                          |  26 +-
 t/t7810-grep.sh                              |  22 +-
 t/t7814-grep-recurse-submodules.sh           |   2 +-
 t/t7900-maintenance.sh                       |  34 +-
 t/t8008-blame-formats.sh                     |   2 +-
 t/t8010-cat-file-filters.sh                  |   2 +-
 t/t8012-blame-colors.sh                      |   2 +-
 t/t9001-send-email.sh                        | 190 +++++-----
 t/t9003-help-autocorrect.sh                  |   6 +-
 t/t9106-git-svn-commit-diff-clobber.sh       |   2 +-
 t/t9107-git-svn-migrate.sh                   |  30 +-
 t/t9110-git-svn-use-svm-props.sh             |  20 +-
 t/t9111-git-svn-use-svnsync-props.sh         |  18 +-
 t/t9114-git-svn-dcommit-merge.sh             |   6 +-
 t/t9116-git-svn-log.sh                       |   8 +-
 t/t9117-git-svn-init-clone.sh                |  12 +-
 t/t9119-git-svn-info.sh                      |  16 +-
 t/t9122-git-svn-author.sh                    |   8 +-
 t/t9130-git-svn-authors-file.sh              |   8 +-
 t/t9138-git-svn-authors-prog.sh              |  14 +-
 t/t9140-git-svn-reset.sh                     |   4 +-
 t/t9153-git-svn-rewrite-uuid.sh              |   4 +-
 t/t9200-git-cvsexportcommit.sh               |   2 +-
 t/t9210-scalar.sh                            |  34 +-
 t/t9211-scalar-clone.sh                      |  16 +-
 t/t9300-fast-import.sh                       |  10 +-
 t/t9350-fast-export.sh                       |  54 +--
 t/t9351-fast-export-anonymize.sh             |  36 +-
 t/t9400-git-cvsserver-server.sh              |   4 +-
 t/t9501-gitweb-standalone-http-status.sh     |  58 ++--
 t/t9502-gitweb-standalone-parse-output.sh    |  38 +-
 t/t9800-git-p4-basic.sh                      |  10 +-
 t/t9801-git-p4-branch.sh                     |  48 +--
 t/t9806-git-p4-options.sh                    |  10 +-
 t/t9807-git-p4-submit.sh                     |   2 +-
 t/t9810-git-p4-rcs.sh                        |   8 +-
 t/t9813-git-p4-preserve-users.sh             |   8 +-
 t/t9814-git-p4-rename.sh                     |   8 +-
 t/t9827-git-p4-change-filetype.sh            |   4 +-
 t/t9832-unshelve.sh                          |   6 +-
 t/t9833-errors.sh                            |   4 +-
 t/t9835-git-p4-metadata-encoding-python2.sh  |  36 +-
 t/t9836-git-p4-metadata-encoding-python3.sh  |  38 +-
 t/t9850-shell.sh                             |   2 +-
 t/t9902-completion.sh                        |  26 +-
 351 files changed, 3215 insertions(+), 2853 deletions(-)
 create mode 100644 t/lint-style/grep-assert.expect
 create mode 100644 t/lint-style/grep-assert.test
 create mode 100644 t/lint-style/grep-fix.expect
 create mode 100644 t/lint-style/grep-fix.test
 create mode 100644 t/lint-style/grep-missing-file.expect
 create mode 100644 t/lint-style/grep-missing-file.test
 create mode 100644 t/lint-style/grep-negated.expect
 create mode 100644 t/lint-style/grep-negated.test
 create mode 100644 t/lint-style/grep-not-assert.expect
 create mode 100644 t/lint-style/grep-not-assert.test

diff --git a/t/Makefile b/t/Makefile
index 3a5fa4ce37..9492195511 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -164,8 +164,10 @@ test-lint-shell-syntax:
 check-shell-parser:
 	@'$(PERL_PATH_SQ)' check-shell-parser.pl
 
+TSOURCED = $(sort $(wildcard t[0-9]*/*.sh))
+
 test-lint-style:
-	@'$(PERL_PATH_SQ)' lint-style.pl $(T) $(THELPERS) $(TPERF)
+	@'$(PERL_PATH_SQ)' lint-style.pl $(T) $(THELPERS) $(TPERF) $(TSOURCED)
 
 check-lint-style:
 	@rc=0; for t in $(LINT_STYLE_TESTS); do \
diff --git a/t/for-each-ref-tests.sh b/t/for-each-ref-tests.sh
index bd2d45c971..6b359d940e 100644
--- a/t/for-each-ref-tests.sh
+++ b/t/for-each-ref-tests.sh
@@ -523,7 +523,7 @@ test_expect_success 'Verify descending sort' '
 
 test_expect_success 'Give help even with invalid sort atoms' '
 	test_expect_code 129 ${git_for_each_ref} --sort=bogus -h >actual 2>&1 &&
-	grep "^usage: ${git_for_each_ref}" actual
+	test_grep "^usage: ${git_for_each_ref}" actual
 '
 
 cat >expected <<\EOF
@@ -622,7 +622,7 @@ test_expect_success 'Quoting style: tcl' '
 for i in "--perl --shell" "-s --python" "--python --tcl" "--tcl --perl"; do
 	test_expect_success "more than one quoting style: $i" "
 		test_must_fail ${git_for_each_ref} $i 2>err &&
-		grep '^error: more than one quoting style' err
+		test_grep '^error: more than one quoting style' err
 	"
 done
 
@@ -1892,7 +1892,7 @@ test_expect_success "${git_for_each_ref} --stdin: fails if extra args" '
 	>in &&
 	test_must_fail ${git_for_each_ref} --format="%(refname)" \
 		--stdin refs/heads/extra <in 2>err &&
-	grep "unknown arguments supplied with --stdin" err
+	test_grep "unknown arguments supplied with --stdin" err
 '
 
 test_expect_success "${git_for_each_ref} --stdin: matches" '
@@ -1955,11 +1955,11 @@ test_expect_success "${git_for_each_ref} with nested tags" '
 
 test_expect_success 'is-base atom with non-commits' '
 	${git_for_each_ref} --format="%(is-base:HEAD) %(refname)" >out 2>err &&
-	grep "(HEAD) refs/heads/main" out &&
+	test_grep "(HEAD) refs/heads/main" out &&
 
 	test_line_count = 2 err &&
-	grep "error: object .* is a commit, not a blob" err &&
-	grep "error: bad tag pointer to" err
+	test_grep "error: object .* is a commit, not a blob" err &&
+	test_grep "error: bad tag pointer to" err
 '
 
 GRADE_FORMAT="%(signature:grade)%0a%(signature:key)%0a%(signature:signer)%0a%(signature:fingerprint)%0a%(signature:primarykeyfingerprint)"
diff --git a/t/lib-bitmap.sh b/t/lib-bitmap.sh
index 62aa6744a6..2de6646128 100644
--- a/t/lib-bitmap.sh
+++ b/t/lib-bitmap.sh
@@ -173,7 +173,7 @@ rev_list_tests_head () {
 
 	test_expect_success "bitmap --objects handles non-commit objects ($state, $branch)" '
 		git rev-list --objects --use-bitmap-index $branch tagged-blob >actual &&
-		grep $blob actual
+		test_grep $blob actual
 	'
 }
 
@@ -242,16 +242,16 @@ basic_bitmap_tests () {
 		GIT_PROGRESS_DELAY=0 \
 			git pack-objects --all --stdout --progress \
 			</dev/null >/dev/null 2>stderr &&
-		grep "Enumerating objects: $count, done" stderr &&
-		grep "pack-reused $count" stderr &&
+		test_grep "Enumerating objects: $count, done" stderr &&
+		test_grep "pack-reused $count" stderr &&
 
 		# now the same but with one non-reused object
 		git commit --allow-empty -m "an extra commit object" &&
 		GIT_PROGRESS_DELAY=0 \
 			git pack-objects --all --stdout --progress \
 			</dev/null >/dev/null 2>stderr &&
-		grep "Enumerating objects: $((count+1)), done" stderr &&
-		grep "pack-reused $count" stderr
+		test_grep "Enumerating objects: $((count+1)), done" stderr &&
+		test_grep "pack-reused $count" stderr
 	'
 }
 
@@ -283,7 +283,7 @@ test_rev_exists () {
 		then
 			test_path_is_file $midx-$(midx_checksum $objdir).rev
 		fi &&
-		grep "\"category\":\"load_midx_revindex\",\"key\":\"source\",\"value\":\"$kind\"" event.trace
+		test_grep "\"category\":\"load_midx_revindex\",\"key\":\"source\",\"value\":\"$kind\"" event.trace
 	'
 }
 
diff --git a/t/lib-bundle-uri-protocol.sh b/t/lib-bundle-uri-protocol.sh
index de09b6b02e..ecf3284297 100644
--- a/t/lib-bundle-uri-protocol.sh
+++ b/t/lib-bundle-uri-protocol.sh
@@ -63,9 +63,9 @@ test_expect_success "connect with $BUNDLE_URI_PROTOCOL:// using protocol v2: no
 		>actual 2>err &&
 
 	# Server responded using protocol v2
-	grep "< version 2" log &&
+	test_grep "< version 2" log &&
 
-	! grep bundle-uri log
+	test_grep ! bundle-uri log
 '
 
 test_expect_success "connect with $BUNDLE_URI_PROTOCOL:// using protocol v2: have bundle-uri" '
@@ -78,10 +78,10 @@ test_expect_success "connect with $BUNDLE_URI_PROTOCOL:// using protocol v2: hav
 		>actual 2>err &&
 
 	# Server responded using protocol v2
-	grep "< version 2" log &&
+	test_grep "< version 2" log &&
 
 	# Server advertised bundle-uri capability
-	grep "< bundle-uri" log
+	test_grep "< bundle-uri" log
 '
 
 test_expect_success "clone with $BUNDLE_URI_PROTOCOL:// using protocol v2: request bundle-uris" '
@@ -95,13 +95,13 @@ test_expect_success "clone with $BUNDLE_URI_PROTOCOL:// using protocol v2: reque
 		>actual 2>err &&
 
 	# Server responded using protocol v2
-	grep "< version 2" log &&
+	test_grep "< version 2" log &&
 
 	# Server advertised bundle-uri capability
-	grep "< bundle-uri" log &&
+	test_grep "< bundle-uri" log &&
 
 	# Client did not issue bundle-uri command
-	! grep "> command=bundle-uri" log &&
+	test_grep ! "> command=bundle-uri" log &&
 
 	GIT_TRACE_PACKET="$PWD/log" \
 	git \
@@ -111,13 +111,13 @@ test_expect_success "clone with $BUNDLE_URI_PROTOCOL:// using protocol v2: reque
 		>actual 2>err &&
 
 	# Server responded using protocol v2
-	grep "< version 2" log &&
+	test_grep "< version 2" log &&
 
 	# Server advertised bundle-uri capability
-	grep "< bundle-uri" log &&
+	test_grep "< bundle-uri" log &&
 
 	# Client issued bundle-uri command
-	grep "> command=bundle-uri" log &&
+	test_grep "> command=bundle-uri" log &&
 
 	GIT_TRACE_PACKET="$PWD/log3" \
 	git \
@@ -128,13 +128,13 @@ test_expect_success "clone with $BUNDLE_URI_PROTOCOL:// using protocol v2: reque
 		>actual 2>err &&
 
 	# Server responded using protocol v2
-	grep "< version 2" log3 &&
+	test_grep "< version 2" log3 &&
 
 	# Server advertised bundle-uri capability
-	grep "< bundle-uri" log3 &&
+	test_grep "< bundle-uri" log3 &&
 
 	# Client did not issue bundle-uri command (--bundle-uri override)
-	! grep "> command=bundle-uri" log3
+	test_grep ! "> command=bundle-uri" log3
 '
 
 # The remaining tests will all assume transfer.bundleURI=true
diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index fc646447d5..a216e5376f 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -275,7 +275,7 @@ test_http_push_nonff () {
 	'
 
 	test_expect_success 'non-fast-forward push show ref status' '
-		grep "^ ! \[rejected\][ ]*$BRANCH -> $BRANCH (non-fast-forward)$" output
+		test_grep "^ ! \[rejected\][ ]*$BRANCH -> $BRANCH (non-fast-forward)$" output
 	'
 
 	test_expect_success 'non-fast-forward push shows help message' '
diff --git a/t/lint-style.pl b/t/lint-style.pl
index 9268577f9b..8b0b44c146 100755
--- a/t/lint-style.pl
+++ b/t/lint-style.pl
@@ -7,6 +7,11 @@
 # Detection uses parsed tokens from the shared shell parser for
 # correct handling of heredocs, $(...), pipes, and quoting.
 # Fixes modify the original file text to preserve formatting.
+#
+# Architecture: the harness (LintParser, parse_commands) tokenizes
+# test bodies and splits them into commands.  Rules are independent
+# functions that examine each command and its surrounding token
+# context to decide if there is a violation.
 
 use strict;
 use warnings;
@@ -31,10 +36,10 @@ do $_lib or die "$0: failed to load $_lib: $@$!\n";
 # on each test body.  Per-file state (file name, raw lines, dirty
 # flag) is stored on the instance before calling parse().
 #
-# Subroutines defined below (parse_commands, check_test_grep_negation,
-# etc.) are in package main and called with the main:: prefix.
-# File-scoped lexicals ($fix_mode, $has_fixable, etc.) are visible
-# across packages since 'package' does not introduce a new scope.
+# Subroutines defined below are in package main and called with
+# the main:: prefix.  File-scoped lexicals ($fix_mode, etc.) are
+# visible across packages since 'package' does not introduce a
+# new scope.
 package LintParser;
 our @ISA = ('ScriptParser');
 
@@ -43,6 +48,9 @@ package main;
 my $exit_code = 0;
 my $has_fixable = 0;
 
+my %skip_file = map { $_ => 1 }
+	grep { m{(?:test-lib-functions|lib-rebase)\.sh$} } @ARGV;
+
 sub err {
 	my ($file, $lineno, $line, $msg, %opts) = @_;
 	$line =~ s/^\s+//;
@@ -53,9 +61,8 @@ sub err {
 	$exit_code = 1 unless $fix_mode && $opts{fixable};
 }
 
-# Report a lint violation found by a rule.  In --fix mode, apply
-# the regex substitution on the raw line and report success.
-# Otherwise just report.  Returns 1 if the line was modified.
+# Report a lint violation.  In --fix mode, apply the regex
+# substitution on the raw line.  Returns 1 if modified.
 sub report_violation {
 	my ($file, $cmd, $line_ref, $match, $fix, $from) = @_;
 	my $lineno = $cmd->{lineno};
@@ -77,46 +84,70 @@ sub report_violation {
 	return 0;
 }
 
+# --- Harness: tokenize and split into commands ---
+#
 # Split a token stream into commands at &&, ||, ;;, and \n.
+# Each command is {tokens => [...], lineno => N, token_pos => I}
+# where token_pos is the index in @all_tokens where the command's
+# first token appeared (so rules can look backward for context).
 sub parse_commands {
-	my ($content) = @_;
-	my $parser = ShellParser->new(\$content);
-	my @all_tokens = $parser->parse();
-
+	my ($all_tokens) = @_;
 	my @commands;
 	my @current;
 	my $lineno = 1;
+	my $first_pos = 0;
+
+	my %shell_keyword;
+	@shell_keyword{qw(if then else elif fi for do done
+			   while until case in esac)} = ();
 
-	for (my $ti = 0; $ti < @all_tokens; $ti++) {
-		my $text = $all_tokens[$ti]->[0];
+	for (my $ti = 0; $ti < @$all_tokens; $ti++) {
+		my $text = $all_tokens->[$ti]->[0];
 		if ($text =~ /^(?:&&|\|\||;;|\n)$/) {
+			# Command separators: flush current command
+			if (@current) {
+				push @commands, {
+					tokens    => [@current],
+					lineno    => $lineno,
+					token_pos => $first_pos,
+				};
+				@current = ();
+			}
+		} elsif ($text =~ /^[{}()|]$/ || exists $shell_keyword{$text}) {
+			# Shell structural tokens and keywords:
+			# flush current command (these are boundaries,
+			# not part of the command's arguments)
 			if (@current) {
 				push @commands, {
-					tokens => [@current],
-					lineno => $lineno,
+					tokens    => [@current],
+					lineno    => $lineno,
+					token_pos => $first_pos,
 				};
 				@current = ();
 			}
 		} else {
-			$lineno = $all_tokens[$ti]->[3]
-				if !@current && defined $all_tokens[$ti]->[3];
+			if (!@current) {
+				# Record line number of the first token
+				$lineno = $all_tokens->[$ti]->[3]
+					if defined $all_tokens->[$ti]->[3];
+				$first_pos = $ti;
+			}
 			push @current, $text;
 		}
 	}
 	if (@current) {
 		push @commands, {
-			tokens => [@current],
-			lineno => $lineno,
+			tokens    => [@current],
+			lineno    => $lineno,
+			token_pos => $first_pos,
 		};
 	}
 	return @commands;
 }
 
 # --- Rule: '! test_grep' should be 'test_grep !' ---
-# Shell-level negation suppresses test_grep's diagnostic output
-# on failure.  Built-in negation preserves it.
 sub check_test_grep_negation {
-	my ($cmd, $file, $line_ref) = @_;
+	my ($cmd, $file, $line_ref, $all_tokens) = @_;
 	my @tokens = @{$cmd->{tokens}};
 	return unless @tokens >= 2 && $tokens[0] eq '!' && $tokens[1] eq 'test_grep';
 
@@ -124,15 +155,197 @@ sub check_test_grep_negation {
 		qr/!\s*test_grep/, 'test_grep !', '! test_grep');
 }
 
-# Map parsed commands back to raw file lines for --fix.
-# Detection uses parsed tokens (correct handling of quoting,
-# heredocs, pipes) but fixes must modify the original text
-# to preserve formatting.
+# --- Rule: bare 'grep' should be 'test_grep' ---
+
+# Check if this command is in a filter context by looking at
+# the surrounding tokens in the stream.  This is grep-rule
+# specific: it knows what contexts make a grep not an assertion.
+sub is_filter_context {
+	my ($all_tokens, $cmd) = @_;
+	my $pos = $cmd->{token_pos};
+
+	# Scan backward to the previous command separator.
+	# If we find '|', this command is part of a pipeline.
+	# If we find if/elif/while/until, it's a condition.
+	for (my $j = $pos - 1; $j >= 0; $j--) {
+		my $t = $all_tokens->[$j]->[0];
+		# Stop at command separators (but not \n after |)
+		last if $t =~ /^(?:&&|\|\||;;)$/;
+		if ($t eq "\n") {
+			# \n after | is a line continuation, keep scanning
+			next if $j > 0 && $all_tokens->[$j - 1]->[0] eq '|';
+			last;
+		}
+		return 1 if $t eq '|';
+		return 1 if $t =~ /^(?:if|elif|while|until)$/;
+		# for ... in ITEMS ... do: if we're between 'in' and 'do',
+		# we're in a value list, not a command
+		return 1 if $t eq 'in';
+	}
+
+	# Forward: pipe after command
+	for (my $j = $pos + @{$cmd->{tokens}}; $j < @$all_tokens; $j++) {
+		my $t = $all_tokens->[$j]->[0];
+		last if $t =~ /^(?:&&|\|\||;;|\n)$/;
+		return 1 if $t eq '|';
+	}
+
+	# { cmd; } >output
+	return 1 if is_in_redirected_brace($all_tokens, $pos);
+
+	return 0;
+}
+
+# Check if position $pos is inside a brace group whose output is
+# redirected: { grep ...; } >file.  Scan backward for the enclosing
+# '{', then forward for the matching '}', and check what follows it.
+sub is_in_redirected_brace {
+	my ($all_tokens, $pos) = @_;
+	my $brace_depth = 0;
+	for (my $j = $pos - 1; $j >= 0; $j--) {
+		my $t = $all_tokens->[$j]->[0];
+		$brace_depth++ if $t eq '}';
+		if ($t eq '{') {
+			return 0 if $brace_depth > 0;
+			$brace_depth--;
+			# Found our enclosing '{'. Find matching '}'
+			my $depth = 1;
+			for (my $k = $j + 1; $k < @$all_tokens; $k++) {
+				$depth++ if $all_tokens->[$k]->[0] eq '{';
+				$depth-- if $all_tokens->[$k]->[0] eq '}';
+				if ($depth == 0) {
+					my $after = $k + 1 < @$all_tokens ?
+						$all_tokens->[$k + 1]->[0] : '';
+					return $after =~ /^>{1,2}/;
+				}
+			}
+			return 0;
+		}
+	}
+	return 0;
+}
+
+# Classify a grep command: assertion, filter, or bug.
+#
+# Returns:
+#   1  assertion (PATTERN + FILE), can be converted to test_grep
+#   0  not a grep, or grep used as a filter
+#  -1  likely bug (e.g., missing file argument)
+sub is_grep_assertion {
+	my ($cmd, $all_tokens) = @_;
+	my @tokens = @{$cmd->{tokens}};
+
+	# Find grep, possibly after "!"
+	my $i = 0;
+	$i++ if $tokens[0] eq '!';
+	return 0 unless defined $tokens[$i] && $tokens[$i] eq 'grep';
+	return 0 if grep { $_ eq 'test_grep' } @tokens;
+
+	# Check surrounding context (pipes, control flow, brace redirects)
+	return 0 if is_filter_context($all_tokens, $cmd);
+
+	$i++;  # skip 'grep'
+
+	# Check grep's own flags and arguments
+	my @positional;
+	my $has_pattern_flag = 0;
+	my $end_of_flags = 0;
+	while ($i < @tokens) {
+		my $tok = $tokens[$i];
+		if ($tok eq '|' || $tok eq '<') {
+			return 0;
+		}
+		if ($tok =~ /^>{1,2}$/) {
+			# Stdout redirect means filter (grep ... >out).
+			# Stderr redirect (2>err) is fine: skip the fd
+			# and the target, and keep classifying.
+			my $prev = $i > 0 ? $tokens[$i - 1] : '';
+			return 0 unless $prev =~ /^\d+$/ && $prev >= 2;
+			pop @positional if @positional && $positional[-1] eq $prev;
+			$i += 2;
+			next;
+		}
+		if (!$end_of_flags && $tok =~ /^-\w*[clLrR]/) {
+			return 0;
+		}
+		if (!$end_of_flags && $tok eq '--') {
+			$end_of_flags = 1;
+		} elsif (!$end_of_flags && $tok =~ /^-\w*[ef]$/) {
+			$has_pattern_flag = 1;
+			$i++;
+		} elsif (!$end_of_flags && $tok =~ /^-/) {
+			# skip other flags
+		} else {
+			push @positional, $tok;
+		}
+		$i++;
+	}
+
+	my $need = $has_pattern_flag ? 1 : 2;
+	return 0 if !@positional && !$has_pattern_flag;
+	return -1 if @positional < $need;
+	return 0 if $positional[-1] =~ /^-/;
+	return 1;
+}
+
+sub check_bare_grep {
+	my ($cmd, $file, $line_ref, $all_tokens) = @_;
+	my @tokens = @{$cmd->{tokens}};
+
+	my $result = is_grep_assertion($cmd, $all_tokens);
+	return unless $result;
+
+	if ($result == -1) {
+		err $file, $cmd->{lineno}, join(' ', @tokens),
+			"grep assertion appears to be missing a file argument";
+		return 0;
+	}
+
+	# Determine negation and -q flag
+	my $negated = $tokens[0] eq '!';
+	my $has_q = 0;
+	my ($pre_q, $post_q) = ('', '');
+	for my $tok (@tokens) {
+		if ($tok =~ /^-(\w*)q(\w*)$/) {
+			$has_q = 1;
+			($pre_q, $post_q) = ($1, $2);
+			last;
+		}
+		last if $tok !~ /^-/ && $tok ne '!' && $tok ne 'grep';
+	}
+
+	# Build the replacement
+	my $fix = "test_grep";
+	$fix .= " !" if $negated;
+	if ($has_q) {
+		my $rest = "$pre_q$post_q";
+		$fix .= " -$rest" if $rest;
+	}
+
+	# Build the match pattern
+	my $neg_match = $negated ? '!\s*' : '\b';
+	my $neg_from  = $negated ? '! '   : '';
+	my ($match, $from);
+	if ($has_q) {
+		$match = qr/${neg_match}grep\s+-\w*q\w*/;
+		$from  = "${neg_from}grep -${pre_q}q${post_q}";
+	} else {
+		$match = qr/${neg_match}grep\b/;
+		$from  = "${neg_from}grep";
+	}
+
+	return report_violation($file, $cmd, $line_ref,
+		$match, $fix, $from);
+}
+
+# --- Harness: LintParser.check_test ---
+#
+# Called by ScriptParser::parse_cmd for each test_expect_success
+# or test_expect_failure block.  Extracts the body, tokenizes it,
+# splits into commands, and runs each rule.
 package LintParser;
 
 sub check_test {
-	# Called by ScriptParser::parse_cmd for each test_expect_success
-	# or test_expect_failure block.
 	my $self = shift @_;
 	my $title = ScriptParser::unwrap(shift @_);
 
@@ -157,25 +370,37 @@ sub check_test {
 	}
 	return unless $body;
 
+	# Tokenize the body once; commands and rules share the stream
+	my $parser = ShellParser->new(\$body);
+	my @all_tokens = $parser->parse();
+	my @commands = main::parse_commands(\@all_tokens);
+
 	# Map each command back to its file line number.
 	# $lineno_base is where the body starts in the file;
 	# $cmd->{lineno} is relative to the body (starting at 1).
 	my $raw_lines = $self->{raw_lines};
-	for my $cmd (main::parse_commands($body)) {
+	for my $cmd (@commands) {
 		my $ln = ($cmd->{lineno} || 0) + $lineno_base - 1;
 		$cmd->{lineno} = $ln;
 		next unless $ln >= 1 && $ln <= @$raw_lines;
 		next if $raw_lines->[$ln - 1] =~ /#.*lint-ok/;
 
-		if (main::check_test_grep_negation($cmd, $self->{file}, \$raw_lines->[$ln - 1])) {
-			$self->{dirty} = 1;
-		}
+		my $line_ref = \$raw_lines->[$ln - 1];
+		# Stop after the first fix: later rules should not
+		# re-match against already-modified text.
+		my $modified = 0;
+		$modified ||= main::check_test_grep_negation(
+			$cmd, $self->{file}, $line_ref, \@all_tokens);
+		$modified ||= main::check_bare_grep(
+			$cmd, $self->{file}, $line_ref, \@all_tokens);
+		$self->{dirty} = 1 if $modified;
 	}
 }
 
 package main;
 
 for my $file (@ARGV) {
+	next if $skip_file{$file};
 	# :unix:crlf strips \r on Windows (same as chainlint.pl)
 	open(my $fh, '<:unix:crlf', $file) or die "$0: $file: $!\n";
 	my @raw_lines = <$fh>;
diff --git a/t/lint-style/grep-assert.expect b/t/lint-style/grep-assert.expect
new file mode 100644
index 0000000000..93c518ed43
--- /dev/null
+++ b/t/lint-style/grep-assert.expect
@@ -0,0 +1,13 @@
+lint-style/grep-assert.test:2: error: replace 'grep' with 'test_grep': grep "pattern" actual
+lint-style/grep-assert.test:3: error: replace 'grep' with 'test_grep': grep -E "extended" actual
+lint-style/grep-assert.test:4: error: replace 'grep' with 'test_grep': grep -e "explicit" actual
+lint-style/grep-assert.test:5: error: replace 'grep' with 'test_grep': grep -f patterns.txt actual
+lint-style/grep-assert.test:6: error: replace 'grep' with 'test_grep': grep -Fe "fixed-explicit" actual
+lint-style/grep-assert.test:7: error: replace 'grep' with 'test_grep': grep "^-looks-like-flag" actual
+lint-style/grep-assert.test:8: error: replace 'grep' with 'test_grep': grep -v "inverted" actual
+lint-style/grep-assert.test:9: error: replace 'grep' with 'test_grep': grep -- "-e" actual
+lint-style/grep-assert.test:10: error: replace 'grep' with 'test_grep': grep "with-stderr-redirect" actual 2 > err
+lint-style/grep-assert.test:12: error: replace 'grep' with 'test_grep': grep "after-or" actual
+lint-style/grep-assert.test:17: error: replace 'grep' with 'test_grep': grep "after-pipe" actual
+lint-style/grep-assert.test:22: error: replace 'grep' with 'test_grep': grep "inside-case" actual
+hint: run with --fix to apply the suggested replacements.
diff --git a/t/lint-style/grep-assert.test b/t/lint-style/grep-assert.test
new file mode 100644
index 0000000000..1567285754
--- /dev/null
+++ b/t/lint-style/grep-assert.test
@@ -0,0 +1,24 @@
+test_expect_success 'grep assertions' '
+	grep "pattern" actual &&
+	grep -E "extended" actual &&
+	grep -e "explicit" actual &&
+	grep -f patterns.txt actual &&
+	grep -Fe "fixed-explicit" actual &&
+	grep "^-looks-like-flag" actual &&
+	grep -v "inverted" actual &&
+	grep -- "-e" actual &&
+	grep "with-stderr-redirect" actual 2>err &&
+	cmd ||
+	grep "after-or" actual
+'
+
+test_expect_success 'pipe only suppresses first command' '
+	cmd |
+	grep "piped" && grep "after-pipe" actual
+'
+
+test_expect_success 'case pattern does not hide assertion' '
+	case foo in
+	*) grep "inside-case" actual ;;
+	esac
+'
diff --git a/t/lint-style/grep-fix.expect b/t/lint-style/grep-fix.expect
new file mode 100644
index 0000000000..04849634c6
--- /dev/null
+++ b/t/lint-style/grep-fix.expect
@@ -0,0 +1,16 @@
+test_expect_success 'all fixable forms' '
+	test_grep "pattern" actual &&
+	test_grep -E "extended" actual &&
+	test_grep "quiet" actual &&
+	test_grep -F "combined" actual &&
+	test_grep -i "quiet-insensitive" actual &&
+	test_grep ! "negated" actual &&
+	test_grep ! "neg-quiet" actual &&
+	test_grep ! "shell-neg" actual &&
+	test_grep -e "explicit" actual &&
+	test_grep -Fe "fixed-explicit" actual &&
+	test_grep -f patterns.txt actual &&
+	test_grep -- "-e" actual &&
+	test_grep "continuation" \
+		actual
+'
diff --git a/t/lint-style/grep-fix.test b/t/lint-style/grep-fix.test
new file mode 100644
index 0000000000..a9202fc177
--- /dev/null
+++ b/t/lint-style/grep-fix.test
@@ -0,0 +1,16 @@
+test_expect_success 'all fixable forms' '
+	grep "pattern" actual &&
+	grep -E "extended" actual &&
+	grep -q "quiet" actual &&
+	grep -qF "combined" actual &&
+	grep -qi "quiet-insensitive" actual &&
+	! grep "negated" actual &&
+	! grep -q "neg-quiet" actual &&
+	! test_grep "shell-neg" actual &&
+	grep -e "explicit" actual &&
+	grep -Fe "fixed-explicit" actual &&
+	grep -f patterns.txt actual &&
+	grep -- "-e" actual &&
+	grep "continuation" \
+		actual
+'
diff --git a/t/lint-style/grep-missing-file.expect b/t/lint-style/grep-missing-file.expect
new file mode 100644
index 0000000000..8d4dc585b5
--- /dev/null
+++ b/t/lint-style/grep-missing-file.expect
@@ -0,0 +1,4 @@
+lint-style/grep-missing-file.test:2: error: grep assertion appears to be missing a file argument: grep "pattern"
+lint-style/grep-missing-file.test:3: error: grep assertion appears to be missing a file argument: ! grep "negated"
+lint-style/grep-missing-file.test:4: error: grep assertion appears to be missing a file argument: grep -e "pattern-flag-no-file"
+lint-style/grep-missing-file.test:5: error: grep assertion appears to be missing a file argument: grep -f patterns.txt
diff --git a/t/lint-style/grep-missing-file.test b/t/lint-style/grep-missing-file.test
new file mode 100644
index 0000000000..aac0528dfc
--- /dev/null
+++ b/t/lint-style/grep-missing-file.test
@@ -0,0 +1,6 @@
+test_expect_success 'grep missing file argument' '
+	grep "pattern" &&
+	! grep "negated" &&
+	grep -e "pattern-flag-no-file" &&
+	grep -f patterns.txt
+'
diff --git a/t/lint-style/grep-negated.expect b/t/lint-style/grep-negated.expect
new file mode 100644
index 0000000000..7029b5544a
--- /dev/null
+++ b/t/lint-style/grep-negated.expect
@@ -0,0 +1,5 @@
+lint-style/grep-negated.test:2: error: replace '! grep' with 'test_grep !': ! grep "pattern" actual
+lint-style/grep-negated.test:3: error: replace '! grep' with 'test_grep !': ! grep -i "insensitive" actual
+lint-style/grep-negated.test:7: error: replace '! grep -q' with 'test_grep !': ! grep -q "pattern" actual
+lint-style/grep-negated.test:8: error: replace '! grep -qF' with 'test_grep ! -F': ! grep -qF "combined" actual
+hint: run with --fix to apply the suggested replacements.
diff --git a/t/lint-style/grep-negated.test b/t/lint-style/grep-negated.test
new file mode 100644
index 0000000000..862a93b93b
--- /dev/null
+++ b/t/lint-style/grep-negated.test
@@ -0,0 +1,9 @@
+test_expect_success 'negated grep' '
+	! grep "pattern" actual &&
+	! grep -i "insensitive" actual
+'
+
+test_expect_success 'negated grep -q' '
+	! grep -q "pattern" actual &&
+	! grep -qF "combined" actual
+'
diff --git a/t/lint-style/grep-not-assert.expect b/t/lint-style/grep-not-assert.expect
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/t/lint-style/grep-not-assert.test b/t/lint-style/grep-not-assert.test
new file mode 100644
index 0000000000..a2c38ae4b1
--- /dev/null
+++ b/t/lint-style/grep-not-assert.test
@@ -0,0 +1,43 @@
+test_expect_success 'grep used as filter (not assertion)' '
+	grep "pattern" file | wc -l &&
+	grep "pattern" file >output &&
+	grep "pattern" file 1>output &&
+	grep -c "count" file &&
+	grep -ci "count-insensitive" file &&
+	grep -l "list" file &&
+	grep -rl "recursive-list" dir &&
+	grep -L "list-without" file1 file2 &&
+	result=$(grep "pattern" file) &&
+	result=$(echo $(grep "nested-subshell" file)) &&
+	grep "pattern" <stdin &&
+	grep "pattern" file && # lint-ok
+	cmd | grep "pattern-only" &&
+	cmd |
+	grep "cross-line-pipe" &&
+	grep -r "recursive" dir
+'
+
+test_expect_success 'grep in control flow (not assertion)' '
+	if grep "condition" file
+	then
+		echo yes
+	elif grep "other-condition" file
+	then
+		echo no
+	fi
+'
+
+test_expect_success 'grep in brace group with redirect' '
+	{ grep "captured" out; } >result
+'
+
+test_expect_success 'grep in for-in value list' '
+	for cmd in grep sed awk; do
+		echo "$cmd"
+	done
+'
+
+test_expect_success 'grep in subshell' '
+	(cd sub && grep "pattern" file >output) &&
+	(cmd | grep "piped-in-subshell")
+'
diff --git a/t/pack-refs-tests.sh b/t/pack-refs-tests.sh
index d76b087b09..a800177446 100644
--- a/t/pack-refs-tests.sh
+++ b/t/pack-refs-tests.sh
@@ -195,7 +195,7 @@ test_expect_success 'delete ref while another dangling packed ref' '
 test_expect_success 'pack ref directly below refs/' '
 	git update-ref refs/top HEAD &&
 	git ${pack_refs} --all --prune &&
-	grep refs/top .git/packed-refs &&
+	test_grep refs/top .git/packed-refs &&
 	test_path_is_missing .git/refs/top
 '
 
diff --git a/t/show-ref-exists-tests.sh b/t/show-ref-exists-tests.sh
index 36e8e9df33..1351f690eb 100644
--- a/t/show-ref-exists-tests.sh
+++ b/t/show-ref-exists-tests.sh
@@ -19,7 +19,7 @@ test_expect_success '--exists with missing reference' '
 
 test_expect_success '--exists does not use DWIM' '
 	test_expect_code 2 ${git_show_ref_exists} $GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME 2>err &&
-	grep "reference does not exist" err
+	test_grep "reference does not exist" err
 '
 
 test_expect_success '--exists with HEAD' '
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 2b63e1c86c..7bd1f4e7b7 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -743,7 +743,7 @@ test_expect_success 'subtest: lazy prereqs do not turn off tracing' '
 	test_done
 	EOF
 
-	grep "echo trace" lazy-prereq-and-tracing/err
+	test_grep "echo trace" lazy-prereq-and-tracing/err
 '
 
 test_expect_success 'subtest: tests clean up after themselves' '
@@ -815,7 +815,7 @@ test_expect_success 'subtest: test_atexit is run' '
 
 test_expect_success 'test_oid provides sane info by default' '
 	test_oid zero >actual &&
-	grep "^00*\$" actual &&
+	test_grep "^00*\$" actual &&
 	rawsz="$(test_oid rawsz)" &&
 	hexsz="$(test_oid hexsz)" &&
 	# +1 accounts for the trailing newline
@@ -827,7 +827,7 @@ test_expect_success 'test_oid can look up data for SHA-1' '
 	test_when_finished "test_detect_hash" &&
 	test_set_hash sha1 &&
 	test_oid zero >actual &&
-	grep "^00*\$" actual &&
+	test_grep "^00*\$" actual &&
 	rawsz="$(test_oid rawsz)" &&
 	hexsz="$(test_oid hexsz)" &&
 	test $(wc -c <actual) -eq 41 &&
@@ -839,7 +839,7 @@ test_expect_success 'test_oid can look up data for SHA-256' '
 	test_when_finished "test_detect_hash" &&
 	test_set_hash sha256 &&
 	test_oid zero >actual &&
-	grep "^00*\$" actual &&
+	test_grep "^00*\$" actual &&
 	rawsz="$(test_oid rawsz)" &&
 	hexsz="$(test_oid hexsz)" &&
 	test $(wc -c <actual) -eq 65 &&
@@ -884,11 +884,11 @@ test_expect_success 'test_bool_env' '
 		# test script, hence the redirection of fd 7, and aborts
 		# with "exit 1", hence the subshell.
 		! ( test_bool_env envvar true ) 7>err &&
-		grep "error: test_bool_env requires bool values" err &&
+		test_grep "error: test_bool_env requires bool values" err &&
 
 		envvar=true &&
 		! ( test_bool_env envvar invalid ) 7>err &&
-		grep "error: test_bool_env requires bool values" err
+		test_grep "error: test_bool_env requires bool values" err
 	)
 '
 
@@ -1242,12 +1242,12 @@ test_expect_success 'test_must_fail on a failing git command with env' '
 
 test_expect_success 'test_must_fail rejects a non-git command' '
 	! test_must_fail grep ^$ notafile 2>err &&
-	grep -F "test_must_fail: only '"'"'git'"'"' is allowed" err
+	test_grep -F "test_must_fail: only '"'"'git'"'"' is allowed" err
 '
 
 test_expect_success 'test_must_fail rejects a non-git command with env' '
 	! test_must_fail env var1=a var2=b grep ^$ notafile 2>err &&
-	grep -F "test_must_fail: only '"'"'git'"'"' is allowed" err
+	test_grep -F "test_must_fail: only '"'"'git'"'"' is allowed" err
 '
 
 test_done
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index e4d32bb4d2..7dcd1e9d48 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -278,9 +278,9 @@ test_expect_success POSIXPERM 'init creates a new deep directory (umask vs. shar
 		git init --bare --shared=0660 newdir/a/b/c &&
 		test_path_is_dir newdir/a/b/c/refs &&
 		ls -ld newdir/a newdir/a/b > lsab.out &&
-		! grep -v "^drwxrw[sx]r-x" lsab.out &&
+		test_grep ! -v "^drwxrw[sx]r-x" lsab.out &&
 		ls -ld newdir/a/b/c > lsc.out &&
-		! grep -v "^drwxrw[sx]---" lsc.out
+		test_grep ! -v "^drwxrw[sx]---" lsc.out
 	)
 '
 
@@ -619,7 +619,7 @@ test_expect_success DEFAULT_REPO_FORMAT 'extensions.refStorage is not allowed wi
 	git init refstorage &&
 	git -C refstorage config extensions.refStorage files &&
 	test_must_fail git -C refstorage rev-parse 2>err &&
-	grep "repo version is 0, but v1-only extension found" err
+	test_grep "repo version is 0, but v1-only extension found" err
 '
 
 test_expect_success DEFAULT_REPO_FORMAT 'extensions.refStorage with files backend' '
@@ -637,7 +637,7 @@ test_expect_success DEFAULT_REPO_FORMAT 'extensions.refStorage with unknown back
 	git -C refstorage config core.repositoryformatversion 1 &&
 	git -C refstorage config extensions.refStorage garbage &&
 	test_must_fail git -C refstorage rev-parse 2>err &&
-	grep "invalid value for ${SQ}extensions.refstorage${SQ}: ${SQ}garbage${SQ}" err
+	test_grep "invalid value for ${SQ}extensions.refstorage${SQ}: ${SQ}garbage${SQ}" err
 '
 
 test_expect_success 'init with GIT_DEFAULT_REF_FORMAT=garbage' '
@@ -848,8 +848,8 @@ test_expect_success MINGW 'redirect std handles' '
 		GIT_REDIRECT_STDOUT=output.txt \
 		GIT_REDIRECT_STDERR="2>&1" \
 		git rev-parse --git-dir --verify refs/invalid &&
-	grep "^\\.git\$" output.txt &&
-	grep "Needed a single revision" output.txt
+	test_grep "^\\.git\$" output.txt &&
+	test_grep "Needed a single revision" output.txt
 '
 
 test_expect_success '--initial-branch' '
@@ -862,14 +862,14 @@ test_expect_success '--initial-branch' '
 	git init --initial-branch=ignore initial-branch-option 2>err &&
 	test_grep "ignored --initial-branch" err &&
 	git -C initial-branch-option symbolic-ref HEAD >actual &&
-	grep hello actual
+	test_grep hello actual
 '
 
 test_expect_success 'overridden default initial branch name (config)' '
 	test_config_global init.defaultBranch nmb &&
 	GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME= git init initial-branch-config &&
 	git -C initial-branch-config symbolic-ref HEAD >actual &&
-	grep nmb actual
+	test_grep nmb actual
 '
 
 test_expect_success 'advice on unconfigured init.defaultBranch' '
@@ -907,7 +907,7 @@ test_expect_success 'overridden default main branch name (env)' '
 	test_config_global init.defaultBranch nmb &&
 	GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=env git init main-branch-env &&
 	git -C main-branch-env symbolic-ref HEAD >actual &&
-	grep env actual
+	test_grep env actual
 '
 
 test_expect_success 'invalid default branch name' '
diff --git a/t/t0008-ignores.sh b/t/t0008-ignores.sh
index d77a179bdd..ed95faf327 100755
--- a/t/t0008-ignores.sh
+++ b/t/t0008-ignores.sh
@@ -790,8 +790,8 @@ test_expect_success 'existing file and directory' '
 	>one &&
 	mkdir top-level-dir &&
 	git check-ignore one top-level-dir >actual &&
-	grep one actual &&
-	grep top-level-dir actual
+	test_grep one actual &&
+	test_grep top-level-dir actual
 '
 
 test_expect_success 'existing directory and file' '
@@ -800,8 +800,8 @@ test_expect_success 'existing directory and file' '
 	>one &&
 	mkdir top-level-dir &&
 	git check-ignore top-level-dir one >actual &&
-	grep one actual &&
-	grep top-level-dir actual
+	test_grep one actual &&
+	test_grep top-level-dir actual
 '
 
 test_expect_success 'exact prefix matching (with root)' '
diff --git a/t/t0009-git-dir-validation.sh b/t/t0009-git-dir-validation.sh
index 33d21ed9ea..4cba478e50 100755
--- a/t/t0009-git-dir-validation.sh
+++ b/t/t0009-git-dir-validation.sh
@@ -35,7 +35,7 @@ test_expect_success PIPE 'setup: .git as a FIFO (named pipe) is rejected' '
 		cd parent/fifo-trap &&
 		mkfifo .git &&
 		test_must_fail git rev-parse --git-dir 2>stderr &&
-		grep "not a regular file" stderr
+		test_grep "not a regular file" stderr
 	)
 '
 
@@ -47,7 +47,7 @@ test_expect_success SYMLINKS,PIPE 'setup: .git as a symlink to a FIFO is rejecte
 		mkfifo target-fifo &&
 		ln -s target-fifo .git &&
 		test_must_fail git rev-parse --git-dir 2>stderr &&
-		grep "not a regular file" stderr
+		test_grep "not a regular file" stderr
 	)
 '
 
@@ -58,7 +58,7 @@ test_expect_success 'setup: .git with garbage content is rejected' '
 		cd parent/garbage-trap &&
 		echo "garbage" >.git &&
 		test_must_fail git rev-parse --git-dir 2>stderr &&
-		grep "invalid gitfile format" stderr
+		test_grep "invalid gitfile format" stderr
 	)
 '
 
diff --git a/t/t0012-help.sh b/t/t0012-help.sh
index c33501bdcd..48d128ad04 100755
--- a/t/t0012-help.sh
+++ b/t/t0012-help.sh
@@ -131,8 +131,8 @@ test_expect_success 'git help succeeds without git.html' '
 
 test_expect_success 'git help --user-interfaces' '
 	git help --user-interfaces >help.output &&
-	grep "^   attributes   " help.output &&
-	grep "^   mailmap   " help.output
+	test_grep "^   attributes   " help.output &&
+	test_grep "^   mailmap   " help.output
 '
 
 test_expect_success 'git help -c' '
diff --git a/t/t0013-sha1dc.sh b/t/t0013-sha1dc.sh
index ce3d81227a..3ea3169d92 100755
--- a/t/t0013-sha1dc.sh
+++ b/t/t0013-sha1dc.sh
@@ -16,7 +16,7 @@ fi
 test_expect_success 'test-sha1 detects shattered pdf' '
 	test_must_fail test-tool sha1 <"$TEST_DATA/shattered-1.pdf" 2>err &&
 	test_grep collision err &&
-	grep 38762cf7f55934b34d179ae6a4c80cadccbb7f0a err
+	test_grep 38762cf7f55934b34d179ae6a4c80cadccbb7f0a err
 '
 
 test_done
diff --git a/t/t0017-env-helper.sh b/t/t0017-env-helper.sh
index 32fe848179..da02bce0ef 100755
--- a/t/t0017-env-helper.sh
+++ b/t/t0017-env-helper.sh
@@ -88,7 +88,7 @@ test_expect_success 'test-tool env-helper reads config thanks to trace2' '
 	test_must_fail \
 		env HOME="$(pwd)/home" \
 		git config -l 2>err &&
-	grep "exceeded maximum include depth" err &&
+	test_grep "exceeded maximum include depth" err &&
 
 	# This validates that the assumption that we attempt to
 	# read the configuration and fail very early in the start-up
@@ -100,7 +100,7 @@ test_expect_success 'test-tool env-helper reads config thanks to trace2' '
 		test-tool -C no-such-directory \
 		env-helper --type=bool --default=0 \
 		--exit-code GIT_TEST_ENV_HELPER 2>err &&
-	grep "exceeded maximum include depth" err
+	test_grep "exceeded maximum include depth" err
 '
 
 test_done
diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh
index f0d50d769e..50994a6ada 100755
--- a/t/t0021-conversion.sh
+++ b/t/t0021-conversion.sh
@@ -731,7 +731,7 @@ test_expect_success 'process filter should restart after unexpected write failur
 		rm -f debug.log &&
 		git checkout --quiet --no-progress . 2>git-stderr.log &&
 
-		grep "smudge write error" git-stderr.log &&
+		test_grep "smudge write error" git-stderr.log &&
 		test_grep "error: external filter" git-stderr.log &&
 
 		cat >expected.log <<-EOF &&
@@ -853,7 +853,7 @@ test_expect_success 'invalid process filter must fail (and not hang!)' '
 
 		cp "$TEST_ROOT/test.o" test.r &&
 		test_must_fail git add . 2>git-stderr.log &&
-		grep "expected git-filter-server" git-stderr.log
+		test_grep "expected git-filter-server" git-stderr.log
 	)
 '
 
@@ -953,7 +953,7 @@ test_expect_success 'missing file in delayed checkout' '
 
 	rm -rf repo-cloned &&
 	test_must_fail git clone repo repo-cloned 2>git-stderr.log &&
-	grep "error: .missing-delay\.a. was not filtered properly" git-stderr.log
+	test_grep "error: .missing-delay\.a. was not filtered properly" git-stderr.log
 '
 
 test_expect_success 'invalid file in delayed checkout' '
@@ -974,7 +974,7 @@ test_expect_success 'invalid file in delayed checkout' '
 
 	rm -rf repo-cloned &&
 	test_must_fail git clone repo repo-cloned 2>git-stderr.log &&
-	grep "error: external filter .* signaled that .unfiltered. is now available although it has not been delayed earlier" git-stderr.log
+	test_grep "error: external filter .* signaled that .unfiltered. is now available although it has not been delayed earlier" git-stderr.log
 '
 
 for mode in 'case' 'utf-8'
@@ -1015,7 +1015,7 @@ do
 
 		git clone $mode-collision $mode-collision-cloned &&
 		# Make sure z was really delayed
-		grep "IN: smudge $dir/z .* \\[DELAYED\\]" $mode-collision-cloned/delayed.log &&
+		test_grep "IN: smudge $dir/z .* \\[DELAYED\\]" $mode-collision-cloned/delayed.log &&
 
 		# Should not create $dir/z at $symlink/z
 		test_path_is_missing $mode-collision/target-dir/z
@@ -1053,7 +1053,7 @@ test_expect_success SYMLINKS,CASE_INSENSITIVE_FS \
 		git commit -m super &&
 
 		git checkout --recurse-submodules . &&
-		grep "IN: smudge A/B/y .* \\[DELAYED\\]" delayed.log &&
+		test_grep "IN: smudge A/B/y .* \\[DELAYED\\]" delayed.log &&
 		test_path_is_missing target-dir/y
 	)
 '
@@ -1144,9 +1144,9 @@ test_expect_success 'delayed checkout correctly reports the number of updated en
 
 		rm *.a &&
 		git checkout . 2>err &&
-		grep "IN: smudge test-delay10.a .* \\[DELAYED\\]" delayed.log &&
-		grep "IN: smudge test-delay11.a .* \\[DELAYED\\]" delayed.log &&
-		grep "Updated 2 paths from the index" err
+		test_grep "IN: smudge test-delay10.a .* \\[DELAYED\\]" delayed.log &&
+		test_grep "IN: smudge test-delay11.a .* \\[DELAYED\\]" delayed.log &&
+		test_grep "Updated 2 paths from the index" err
 	)
 '
 
diff --git a/t/t0029-core-unsetenvvars.sh b/t/t0029-core-unsetenvvars.sh
index baa1b7e85b..975620b389 100755
--- a/t/t0029-core-unsetenvvars.sh
+++ b/t/t0029-core-unsetenvvars.sh
@@ -20,10 +20,10 @@ test_expect_success 'core.unsetenvvars works' '
 	HOBBES=Calvin &&
 	export HOBBES &&
 	git commit --allow-empty -m with 2>err &&
-	grep Calvin err &&
+	test_grep Calvin err &&
 	git -c core.unsetenvvars=FINDUS,HOBBES,CALVIN \
 		commit --allow-empty -m without 2>err &&
-	! grep Calvin err
+	test_grep ! Calvin err
 '
 
 test_done
diff --git a/t/t0030-stripspace.sh b/t/t0030-stripspace.sh
index 43155f6bd8..d6e2f63c59 100755
--- a/t/t0030-stripspace.sh
+++ b/t/t0030-stripspace.sh
@@ -407,12 +407,12 @@ test_expect_success 'strip comments with changed comment string' '
 
 test_expect_success 'newline as commentchar is forbidden' '
 	test_must_fail git -c core.commentChar="$LF" stripspace -s 2>err &&
-	grep "core.commentchar cannot contain newline" err
+	test_grep "core.commentchar cannot contain newline" err
 '
 
 test_expect_success 'empty commentchar is forbidden' '
 	test_must_fail git -c core.commentchar= stripspace -s 2>err &&
-	grep "core.commentchar must have at least one character" err
+	test_grep "core.commentchar must have at least one character" err
 '
 
 test_expect_success '-c with single line' '
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index ca55ea8228..a8348a851c 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -324,13 +324,13 @@ test_expect_success 'non ambiguous option (after two options it abbreviates)' '
 
 test_expect_success 'Alias options do not contribute to abbreviation' '
 	test-tool parse-options --alias-source 123 >output &&
-	grep "^string: 123" output &&
+	test_grep "^string: 123" output &&
 	test-tool parse-options --alias-target 123 >output &&
-	grep "^string: 123" output &&
+	test_grep "^string: 123" output &&
 	test_must_fail test-tool parse-options --alias &&
 	GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS=false \
 	test-tool parse-options --alias 123 >output &&
-	grep "^string: 123" output
+	test_grep "^string: 123" output
 '
 
 cat >typo.err <<\EOF
@@ -582,16 +582,16 @@ test_expect_success 'KEEP_UNKNOWN_OPT works' '
 
 test_expect_success 'NO_INTERNAL_HELP works for -h' '
 	test_expect_code 129 test-tool parse-options-flags --no-internal-help cmd -h 2>err &&
-	grep "^error: unknown switch \`h$SQ" err &&
-	grep "^usage: " err
+	test_grep "^error: unknown switch \`h$SQ" err &&
+	test_grep "^usage: " err
 '
 
 for help_opt in help help-all
 do
 	test_expect_success "NO_INTERNAL_HELP works for --$help_opt" "
 		test_expect_code 129 test-tool parse-options-flags --no-internal-help cmd --$help_opt 2>err &&
-		grep '^error: unknown option \`'$help_opt\' err &&
-		grep '^usage: ' err
+		test_grep '^error: unknown option \`'$help_opt\' err &&
+		test_grep '^usage: ' err
 	"
 done
 
@@ -608,38 +608,38 @@ test_expect_success 'KEEP_UNKNOWN_OPT | NO_INTERNAL_HELP works' '
 
 test_expect_success 'subcommand - no subcommand shows error and usage' '
 	test_expect_code 129 test-tool parse-subcommand cmd 2>err &&
-	grep "^error: need a subcommand" err &&
-	grep ^usage: err
+	test_grep "^error: need a subcommand" err &&
+	test_grep ^usage: err
 '
 
 test_expect_success 'subcommand - subcommand after -- shows error and usage' '
 	test_expect_code 129 test-tool parse-subcommand cmd -- subcmd-one 2>err &&
-	grep "^error: need a subcommand" err &&
-	grep ^usage: err
+	test_grep "^error: need a subcommand" err &&
+	test_grep ^usage: err
 '
 
 test_expect_success 'subcommand - subcommand after --end-of-options shows error and usage' '
 	test_expect_code 129 test-tool parse-subcommand cmd --end-of-options subcmd-one 2>err &&
-	grep "^error: need a subcommand" err &&
-	grep ^usage: err
+	test_grep "^error: need a subcommand" err &&
+	test_grep ^usage: err
 '
 
 test_expect_success 'subcommand - unknown subcommand shows error and usage' '
 	test_expect_code 129 test-tool parse-subcommand cmd nope 2>err &&
-	grep "^error: unknown subcommand: \`nope$SQ" err &&
-	grep ^usage: err
+	test_grep "^error: unknown subcommand: \`nope$SQ" err &&
+	test_grep ^usage: err
 '
 
 test_expect_success 'subcommand - subcommands cannot be abbreviated' '
 	test_expect_code 129 test-tool parse-subcommand cmd subcmd-o 2>err &&
-	grep "^error: unknown subcommand: \`subcmd-o$SQ$" err &&
-	grep ^usage: err
+	test_grep "^error: unknown subcommand: \`subcmd-o$SQ$" err &&
+	test_grep ^usage: err
 '
 
 test_expect_success 'subcommand - no negated subcommands' '
 	test_expect_code 129 test-tool parse-subcommand cmd no-subcmd-one 2>err &&
-	grep "^error: unknown subcommand: \`no-subcmd-one$SQ" err &&
-	grep ^usage: err
+	test_grep "^error: unknown subcommand: \`no-subcmd-one$SQ" err &&
+	test_grep ^usage: err
 '
 
 test_expect_success 'subcommand - simple' '
@@ -709,8 +709,8 @@ test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL + subcommand not given + u
 
 test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL + subcommand not given + unknown option' '
 	test_expect_code 129 test-tool parse-subcommand --subcommand-optional cmd --subcommand-opt 2>err &&
-	grep "^error: unknown option" err &&
-	grep ^usage: err
+	test_grep "^error: unknown option" err &&
+	test_grep ^usage: err
 '
 
 test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL | KEEP_UNKNOWN_OPT + subcommand not given + unknown option' '
@@ -778,28 +778,28 @@ test_expect_success 'subcommand - completion helper' '
 
 test_expect_success 'subcommands are incompatible with STOP_AT_NON_OPTION' '
 	test_must_fail test-tool parse-subcommand --stop-at-non-option cmd subcmd-one 2>err &&
-	grep ^BUG err
+	test_grep ^BUG err
 '
 
 test_expect_success 'subcommands are incompatible with KEEP_UNKNOWN_OPT unless in combination with SUBCOMMAND_OPTIONAL' '
 	test_must_fail test-tool parse-subcommand --keep-unknown-opt cmd subcmd-two 2>err &&
-	grep ^BUG err
+	test_grep ^BUG err
 '
 
 test_expect_success 'subcommands are incompatible with KEEP_DASHDASH unless in combination with SUBCOMMAND_OPTIONAL' '
 	test_must_fail test-tool parse-subcommand --keep-dashdash cmd subcmd-two 2>err &&
-	grep ^BUG err
+	test_grep ^BUG err
 '
 
 test_expect_success 'negative unsigned' '
 	test_must_fail test-tool parse-options --unsigned -1 >out 2>err &&
-	grep "non-negative integer" err &&
+	test_grep "non-negative integer" err &&
 	test_must_be_empty out
 '
 
 test_expect_success 'unsigned with units but no numbers' '
 	test_must_fail test-tool parse-options --unsigned m >out 2>err &&
-	grep "non-negative integer" err &&
+	test_grep "non-negative integer" err &&
 	test_must_be_empty out
 '
 
diff --git a/t/t0041-usage.sh b/t/t0041-usage.sh
index a0f6f134c7..51af7cc030 100755
--- a/t/t0041-usage.sh
+++ b/t/t0041-usage.sh
@@ -13,7 +13,7 @@ test_expect_success 'setup ' '
 
 test_expect_success 'tag --contains <existent_tag>' '
 	git tag --contains "v1.0" >actual 2>actual.err &&
-	grep "v1.0" actual &&
+	test_grep "v1.0" actual &&
 	test_line_count = 0 actual.err
 '
 
diff --git a/t/t0052-simple-ipc.sh b/t/t0052-simple-ipc.sh
index ff98be31a5..838ccc0e46 100755
--- a/t/t0052-simple-ipc.sh
+++ b/t/t0052-simple-ipc.sh
@@ -33,19 +33,19 @@ test_expect_success 'servers cannot share the same path' '
 test_expect_success 'big response' '
 	test-tool simple-ipc send --token=big >actual &&
 	test_line_count -ge 10000 actual &&
-	grep -q "big: [0]*9999\$" actual
+	test_grep "big: [0]*9999\$" actual
 '
 
 test_expect_success 'chunk response' '
 	test-tool simple-ipc send --token=chunk >actual &&
 	test_line_count -ge 10000 actual &&
-	grep -q "big: [0]*9999\$" actual
+	test_grep "big: [0]*9999\$" actual
 '
 
 test_expect_success 'slow response' '
 	test-tool simple-ipc send --token=slow >actual &&
 	test_line_count -ge 100 actual &&
-	grep -q "big: [0]*99\$" actual
+	test_grep "big: [0]*99\$" actual
 '
 
 # Send an IPC with n=100,000 bytes of ballast.  This should be large enough
@@ -54,7 +54,7 @@ test_expect_success 'slow response' '
 #
 test_expect_success 'sendbytes' '
 	test-tool simple-ipc sendbytes --bytecount=100000 --byte=A >actual &&
-	grep "sent:A00100000 rcvd:A00100000" actual
+	test_grep "sent:A00100000 rcvd:A00100000" actual
 '
 
 # Start a series of <threads> client threads that each make <batchsize>
@@ -93,7 +93,7 @@ test_expect_success 'stress test threads' '
 		--batchsize=13 \
 		>actual &&
 	test_line_count = 92 actual &&
-	grep "good 91" actual &&
+	test_grep "good 91" actual &&
 	grep "sent:A" <actual >actual_a &&
 	cat >expect_a <<-EOF &&
 		sent:A00000019 rcvd:A00000019
diff --git a/t/t0061-run-command.sh b/t/t0061-run-command.sh
index 60cfe65979..dc9d77b0e1 100755
--- a/t/t0061-run-command.sh
+++ b/t/t0061-run-command.sh
@@ -97,7 +97,7 @@ test_expect_success POSIXPERM 'run_command reports EACCES' '
 	chmod -x hello.sh &&
 	test_must_fail test-tool run-command run-command ./hello.sh 2>err &&
 
-	grep "fatal: cannot exec.*hello.sh" err
+	test_grep "fatal: cannot exec.*hello.sh" err
 '
 
 test_expect_success POSIXPERM,SANITY 'unreadable directory in PATH' '
diff --git a/t/t0066-dir-iterator.sh b/t/t0066-dir-iterator.sh
index df3e9f5fa5..9fbb41bac5 100755
--- a/t/t0066-dir-iterator.sh
+++ b/t/t0066-dir-iterator.sh
@@ -127,7 +127,7 @@ test_expect_success SYMLINKS 'dir-iterator should not follow symlinks by default
 test_expect_success SYMLINKS 'dir-iterator does not resolve top-level symlinks' '
 	test_must_fail test-tool dir-iterator ./dir5 >out &&
 
-	grep "ENOTDIR" out
+	test_grep "ENOTDIR" out
 '
 
 test_done
diff --git a/t/t0068-for-each-repo.sh b/t/t0068-for-each-repo.sh
index 80b163ea99..55b37d895a 100755
--- a/t/t0068-for-each-repo.sh
+++ b/t/t0068-for-each-repo.sh
@@ -21,23 +21,23 @@ test_expect_success 'run based on configured value' '
 
 	git for-each-repo --config=run.key commit --allow-empty -m "ran" &&
 	git -C one log -1 --pretty=format:%s >message &&
-	grep ran message &&
+	test_grep ran message &&
 	git -C two log -1 --pretty=format:%s >message &&
-	! grep ran message &&
+	test_grep ! ran message &&
 	git -C three log -1 --pretty=format:%s >message &&
-	grep ran message &&
+	test_grep ran message &&
 	git -C ~/four log -1 --pretty=format:%s >message &&
-	grep ran message &&
+	test_grep ran message &&
 
 	git for-each-repo --config=run.key -- commit --allow-empty -m "ran again" &&
 	git -C one log -1 --pretty=format:%s >message &&
-	grep again message &&
+	test_grep again message &&
 	git -C two log -1 --pretty=format:%s >message &&
-	! grep again message &&
+	test_grep ! again message &&
 	git -C three log -1 --pretty=format:%s >message &&
-	grep again message &&
+	test_grep again message &&
 	git -C ~/four log -1 --pretty=format:%s >message &&
-	grep again message &&
+	test_grep again message &&
 
 	git -C three for-each-repo --config=run.key -- \
 		commit --allow-empty -m "ran from worktree" &&
diff --git a/t/t0070-fundamental.sh b/t/t0070-fundamental.sh
index 6b9dcf984b..8f573c2a0e 100755
--- a/t/t0070-fundamental.sh
+++ b/t/t0070-fundamental.sh
@@ -10,7 +10,7 @@ Verify wrappers and compatibility functions.
 
 test_expect_success 'mktemp to nonexistent directory prints filename' '
 	test_must_fail test-tool mktemp doesnotexist/testXXXXXX 2>err &&
-	grep "doesnotexist/test" err
+	test_grep "doesnotexist/test" err
 '
 
 test_expect_success POSIXPERM,SANITY 'mktemp to unwritable directory prints filename' '
@@ -18,7 +18,7 @@ test_expect_success POSIXPERM,SANITY 'mktemp to unwritable directory prints file
 	test_when_finished "chmod +w cannotwrite" &&
 	chmod -w cannotwrite &&
 	test_must_fail test-tool mktemp cannotwrite/testXXXXXX 2>err &&
-	grep "cannotwrite/test" err
+	test_grep "cannotwrite/test" err
 '
 
 test_expect_success 'git_mkstemps_mode does not fail if fd 0 is not open' '
@@ -33,7 +33,7 @@ test_expect_success 'check for a bug in the regex routines' '
 test_expect_success 'incomplete sideband messages are reassembled' '
 	test-tool pkt-line send-split-sideband >split-sideband &&
 	test-tool pkt-line receive-sideband <split-sideband 2>err &&
-	grep "Hello, world" err
+	test_grep "Hello, world" err
 '
 
 test_expect_success 'eof on sideband message is reported' '
diff --git a/t/t0081-find-pack.sh b/t/t0081-find-pack.sh
index 26f017422d..ff9d56fbf1 100755
--- a/t/t0081-find-pack.sh
+++ b/t/t0081-find-pack.sh
@@ -52,17 +52,17 @@ test_expect_success 'add more packfiles' '
 
 	# HEAD^{tree} is in 2 packfiles
 	test-tool find-pack HEAD^{tree} >head_tree_packs &&
-	grep "$head_commit_pack" head_tree_packs &&
-	grep mypackname1 head_tree_packs &&
-	! grep mypackname2 head_tree_packs &&
+	test_grep "$head_commit_pack" head_tree_packs &&
+	test_grep mypackname1 head_tree_packs &&
+	test_grep ! mypackname2 head_tree_packs &&
 	test-tool find-pack --check-count 2 HEAD^{tree} &&
 	! test-tool find-pack --check-count 1 HEAD^{tree} &&
 
 	# HEAD:five.t is also in 2 packfiles
 	test-tool find-pack HEAD:five.t >five_packs &&
-	grep "$head_commit_pack" five_packs &&
-	! grep mypackname1 five_packs &&
-	grep mypackname2 five_packs &&
+	test_grep "$head_commit_pack" five_packs &&
+	test_grep ! mypackname1 five_packs &&
+	test_grep mypackname2 five_packs &&
 	test-tool find-pack -c 2 HEAD:five.t &&
 	! test-tool find-pack --check-count=0 HEAD:five.t
 '
diff --git a/t/t0091-bugreport.sh b/t/t0091-bugreport.sh
index e38ca7a901..81ed41742c 100755
--- a/t/t0091-bugreport.sh
+++ b/t/t0091-bugreport.sh
@@ -40,15 +40,15 @@ test_expect_success 'sanity check "System Info" section' '
 
 	# The beginning should match "git version --build-options" verbatim,
 	# but rather than checking bit-for-bit equality, just test some basics.
-	grep "git version " system &&
-	grep "shell-path: ." system &&
+	test_grep "git version " system &&
+	test_grep "shell-path: ." system &&
 
 	# After the version, there should be some more info.
 	# This is bound to differ from environment to environment,
 	# so we just do some rather high-level checks.
-	grep "uname: ." system &&
-	grep "compiler info: ." system &&
-	grep "zlib." system
+	test_grep "uname: ." system &&
+	test_grep "compiler info: ." system &&
+	test_grep "zlib." system
 '
 
 test_expect_success 'dies if file with same name as report already exists' '
@@ -112,7 +112,7 @@ test_expect_success UNZIP '--diagnose creates diagnostics zip archive' '
 	git bugreport --diagnose -o report -s test >out &&
 
 	zip_path=report/git-diagnostics-test.zip &&
-	grep "Available space" out &&
+	test_grep "Available space" out &&
 	test_path_is_file "$zip_path" &&
 
 	# Check zipped archive content
@@ -120,10 +120,10 @@ test_expect_success UNZIP '--diagnose creates diagnostics zip archive' '
 	test_file_not_empty out &&
 
 	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
-	grep ".git/objects" out &&
+	test_grep ".git/objects" out &&
 
 	"$GIT_UNZIP" -p "$zip_path" objects-local.txt >out &&
-	grep "^Total: [0-9][0-9]*" out &&
+	test_grep "^Total: [0-9][0-9]*" out &&
 
 	# Should not include .git directory contents by default
 	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
@@ -136,7 +136,7 @@ test_expect_success UNZIP '--diagnose=stats excludes .git dir contents' '
 
 	# Includes pack quantity/size info
 	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
-	grep ".git/objects" out &&
+	test_grep ".git/objects" out &&
 
 	# Does not include .git directory contents
 	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
diff --git a/t/t0092-diagnose.sh b/t/t0092-diagnose.sh
index 6cabd6e67b..0bc2b1ed5c 100755
--- a/t/t0092-diagnose.sh
+++ b/t/t0092-diagnose.sh
@@ -8,7 +8,7 @@ test_expect_success UNZIP 'creates diagnostics zip archive' '
 	test_when_finished rm -rf report &&
 
 	git diagnose -o report -s test >out &&
-	grep "Available space" out &&
+	test_grep "Available space" out &&
 
 	zip_path=report/git-diagnostics-test.zip &&
 	test_path_is_file "$zip_path" &&
@@ -18,10 +18,10 @@ test_expect_success UNZIP 'creates diagnostics zip archive' '
 	test_file_not_empty out &&
 
 	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
-	grep ".git/objects" out &&
+	test_grep ".git/objects" out &&
 
 	"$GIT_UNZIP" -p "$zip_path" objects-local.txt >out &&
-	grep "^Total: [0-9][0-9]*" out &&
+	test_grep "^Total: [0-9][0-9]*" out &&
 
 	# Should not include .git directory contents by default
 	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
@@ -34,7 +34,7 @@ test_expect_success UNZIP 'counts loose objects' '
 	git diagnose -o test-count -s 1 >out &&
 	zip_path=test-count/git-diagnostics-1.zip &&
 	"$GIT_UNZIP" -p "$zip_path" objects-local.txt >out &&
-	grep "^Total: [1-9][0-9]* loose objects" out
+	test_grep "^Total: [1-9][0-9]* loose objects" out
 '
 
 test_expect_success UNZIP '--mode=stats excludes .git dir contents' '
@@ -45,7 +45,7 @@ test_expect_success UNZIP '--mode=stats excludes .git dir contents' '
 	# Includes pack quantity/size info
 	zip_path=report/git-diagnostics-test.zip &&
 	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
-	grep ".git/objects" out &&
+	test_grep ".git/objects" out &&
 
 	# Does not include .git directory contents
 	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
@@ -59,7 +59,7 @@ test_expect_success UNZIP '--mode=all includes .git dir contents' '
 	# Includes pack quantity/size info
 	zip_path=report/git-diagnostics-test.zip &&
 	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
-	grep ".git/objects" out &&
+	test_grep ".git/objects" out &&
 
 	# Includes .git directory contents
 	"$GIT_UNZIP" -l "$zip_path" | grep ".git/" &&
diff --git a/t/t0100-previous.sh b/t/t0100-previous.sh
index dd5d9b4e5e..87a9995ea4 100755
--- a/t/t0100-previous.sh
+++ b/t/t0100-previous.sh
@@ -50,7 +50,7 @@ test_expect_success 'merge @{-1}~1' '
 	git checkout main &&
 	git merge @{-1}~1 &&
 	git cat-file commit HEAD >actual &&
-	grep "Merge branch '\''other'\''" actual
+	test_grep "Merge branch '\''other'\''" actual
 '
 
 test_expect_success 'merge @{-100} before checking out that many branches yet' '
diff --git a/t/t0200-gettext-basic.sh b/t/t0200-gettext-basic.sh
index 8853d8afb9..8db26c1ada 100755
--- a/t/t0200-gettext-basic.sh
+++ b/t/t0200-gettext-basic.sh
@@ -16,7 +16,7 @@ test_expect_success 'sanity: $TEXTDOMAIN is git' '
 '
 
 test_expect_success 'xgettext sanity: Perl _() strings are not extracted' '
-    ! grep "A Perl string xgettext will not get" "$GIT_PO_PATH"/is.po
+    test_grep ! "A Perl string xgettext will not get" "$GIT_PO_PATH"/is.po
 '
 
 test_expect_success 'xgettext sanity: Comment extraction with --add-comments' '
@@ -26,8 +26,8 @@ test_expect_success 'xgettext sanity: Comment extraction with --add-comments' '
 '
 
 test_expect_success 'xgettext sanity: Comment extraction with --add-comments stops at statements' '
-    ! grep "This is a phony" "$GIT_PO_PATH"/is.po &&
-    ! grep "the above comment" "$GIT_PO_PATH"/is.po
+    test_grep ! "This is a phony" "$GIT_PO_PATH"/is.po &&
+    test_grep ! "the above comment" "$GIT_PO_PATH"/is.po
 '
 
 test_expect_success GETTEXT 'sanity: $TEXTDOMAINDIR exists without NO_GETTEXT=YesPlease' '
@@ -44,10 +44,10 @@ test_expect_success GETTEXT 'sanity: Icelandic locale was compiled' '
 test_expect_success GETTEXT_LOCALE 'sanity: gettext("") metadata is OK' '
     # Return value may be non-zero
     LANGUAGE=is LC_ALL="$is_IS_locale" gettext "" >zero-expect &&
-    grep "Project-Id-Version: Git" zero-expect &&
-    grep "Git Mailing List <git@vger.kernel.org>" zero-expect &&
-    grep "Content-Type: text/plain; charset=UTF-8" zero-expect &&
-    grep "Content-Transfer-Encoding: 8bit" zero-expect
+    test_grep "Project-Id-Version: Git" zero-expect &&
+    test_grep "Git Mailing List <git@vger.kernel.org>" zero-expect &&
+    test_grep "Content-Type: text/plain; charset=UTF-8" zero-expect &&
+    test_grep "Content-Transfer-Encoding: 8bit" zero-expect
 '
 
 test_expect_success GETTEXT_LOCALE 'sanity: gettext(unknown) is passed through' '
diff --git a/t/t0203-gettext-setlocale-sanity.sh b/t/t0203-gettext-setlocale-sanity.sh
index 0ce1f22eff..d8af97de23 100755
--- a/t/t0203-gettext-setlocale-sanity.sh
+++ b/t/t0203-gettext-setlocale-sanity.sh
@@ -12,7 +12,7 @@ test_expect_success 'git show a ISO-8859-1 commit under C locale' '
 	test_commit "iso-c-commit" iso-under-c &&
 	git show >out 2>err &&
 	test_must_be_empty err &&
-	grep -q "iso-c-commit" out
+	test_grep "iso-c-commit" out
 '
 
 test_expect_success GETTEXT_LOCALE 'git show a ISO-8859-1 commit under a UTF-8 locale' '
@@ -20,7 +20,7 @@ test_expect_success GETTEXT_LOCALE 'git show a ISO-8859-1 commit under a UTF-8 l
 	test_commit "iso-utf8-commit" iso-under-utf8 &&
 	LANGUAGE=is LC_ALL="$is_IS_locale" git show >out 2>err &&
 	test_must_be_empty err &&
-	grep -q "iso-utf8-commit" out
+	test_grep "iso-utf8-commit" out
 '
 
 test_done
diff --git a/t/t0204-gettext-reencode-sanity.sh b/t/t0204-gettext-reencode-sanity.sh
index 28d92bb9b7..48ccddaf7d 100755
--- a/t/t0204-gettext-reencode-sanity.sh
+++ b/t/t0204-gettext-reencode-sanity.sh
@@ -66,22 +66,22 @@ test_expect_success GETTEXT_LOCALE 'gettext: Fetching a UTF-8 msgid -> UTF-8' '
 # eyes.
 test_expect_success GETTEXT_ISO_LOCALE 'gettext: Fetching a UTF-8 msgid -> ISO-8859-1' '
     LANGUAGE=is LC_ALL="$is_IS_iso_locale" gettext "TEST: ‘single’ and “double” quotes" >actual &&
-    grep "einfaldar" actual &&
-    grep "$(echo tvöfaldar | iconv -f UTF-8 -t ISO8859-1)" actual
+    test_grep "einfaldar" actual &&
+    test_grep "$(echo tvöfaldar | iconv -f UTF-8 -t ISO8859-1)" actual
 '
 
 test_expect_success GETTEXT_LOCALE 'gettext.c: git init UTF-8 -> UTF-8' '
     printf "Bjó til tóma Git lind" >expect &&
     LANGUAGE=is LC_ALL="$is_IS_locale" git init repo >actual &&
     test_when_finished "rm -rf repo" &&
-    grep "^$(cat expect) " actual
+    test_grep "^$(cat expect) " actual
 '
 
 test_expect_success GETTEXT_ISO_LOCALE 'gettext.c: git init UTF-8 -> ISO-8859-1' '
     printf "Bjó til tóma Git lind" >expect &&
     LANGUAGE=is LC_ALL="$is_IS_iso_locale" git init repo >actual &&
     test_when_finished "rm -rf repo" &&
-    grep "^$(iconv -f UTF-8 -t ISO8859-1 <expect) " actual
+    test_grep "^$(iconv -f UTF-8 -t ISO8859-1 <expect) " actual
 '
 
 test_done
diff --git a/t/t0210-trace2-normal.sh b/t/t0210-trace2-normal.sh
index 7e1e7af862..beed2b27a5 100755
--- a/t/t0210-trace2-normal.sh
+++ b/t/t0210-trace2-normal.sh
@@ -333,12 +333,12 @@ test_expect_success 'unsafe URLs are redacted by default' '
 
 	GIT_TRACE2="$(pwd)/trace.normal" \
 		git clone https://user:pwd@example.com/ clone &&
-	! grep user:pwd trace.normal &&
+	test_grep ! user:pwd trace.normal &&
 
 	GIT_TRACE2_REDACT=0 GIT_TRACE2="$(pwd)/unredacted.normal" \
 		git clone https://user:pwd@example.com/ clone2 &&
-	grep "start .* clone https://user:pwd@example.com" unredacted.normal &&
-	grep "remote.origin.url=https://user:pwd@example.com" unredacted.normal
+	test_grep "start .* clone https://user:pwd@example.com" unredacted.normal &&
+	test_grep "remote.origin.url=https://user:pwd@example.com" unredacted.normal
 '
 
 test_done
diff --git a/t/t0211-trace2-perf.sh b/t/t0211-trace2-perf.sh
index 760cf69087..665c8b3669 100755
--- a/t/t0211-trace2-perf.sh
+++ b/t/t0211-trace2-perf.sh
@@ -283,13 +283,13 @@ test_expect_success 'unsafe URLs are redacted by default' '
 
 	GIT_TRACE2_PERF="$(pwd)/trace.perf" \
 		git clone https://user:pwd@example.com/ clone &&
-	! grep user:pwd trace.perf &&
+	test_grep ! user:pwd trace.perf &&
 
 	GIT_TRACE2_REDACT=0 GIT_TRACE2_PERF="$(pwd)/unredacted.perf" \
 		git clone https://user:pwd@example.com/ clone2 &&
 	perl "$TEST_DIRECTORY/t0211/scrub_perf.perl" <unredacted.perf >actual &&
-	grep "d0|main|start|.* clone https://user:pwd@example.com" actual &&
-	grep "d0|main|def_param|.*|remote.origin.url:https://user:pwd@example.com" actual
+	test_grep "d0|main|start|.* clone https://user:pwd@example.com" actual &&
+	test_grep "d0|main|def_param|.*|remote.origin.url:https://user:pwd@example.com" actual
 '
 
 # Confirm that the requested command produces a "cmd_name" and a
@@ -358,13 +358,13 @@ test_expect_success LIBCURL \
 
 	perl "$TEST_DIRECTORY/t0211/scrub_perf.perl" <prop.perf >actual &&
 
-	grep "d0|main|cmd_name|.*|_run_dashed_" actual &&
-	grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_dashed_" actual &&
+	test_grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
 
-	grep "d1|main|cmd_name|.*|remote-curl" actual &&
-	grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
+	test_grep "d1|main|cmd_name|.*|remote-curl" actual &&
+	test_grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
 '
 
 # Similarly, `git-http-fetch` is not built from git.c so do a
@@ -389,13 +389,13 @@ test_expect_success LIBCURL \
 
 	perl "$TEST_DIRECTORY/t0211/scrub_perf.perl" <prop.perf >actual &&
 
-	grep "d0|main|cmd_name|.*|_run_dashed_" actual &&
-	grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_dashed_" actual &&
+	test_grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
 
-	grep "d1|main|cmd_name|.*|http-fetch" actual &&
-	grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
+	test_grep "d1|main|cmd_name|.*|http-fetch" actual &&
+	test_grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
 '
 
 # Historically, alias expansion explicitly emitted the def_param
@@ -421,22 +421,22 @@ test_expect_success 'expect def_params during git alias expansion' '
 	perl "$TEST_DIRECTORY/t0211/scrub_perf.perl" <prop.perf >actual &&
 
 	# "git xxx" is first mapped to "git-xxx" and the child will fail.
-	grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_)" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_)" actual &&
 
 	# We unpeel that and substitute "version" into "xxx" (giving
 	# "git version") and update the cmd_name event.
-	grep "d0|main|cmd_name|.*|_run_git_alias_ (_run_dashed_/_run_git_alias_)" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_git_alias_ (_run_dashed_/_run_git_alias_)" actual &&
 
 	# These def_param events could be associated with either of the
 	# above cmd_name events.  It does not matter.
-	grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
+	test_grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
 
 	# The "git version" child sees a different cmd_name hierarchy.
 	# Also test the def_param (only for completeness).
-	grep "d1|main|cmd_name|.*|version (_run_dashed_/_run_git_alias_/version)" actual &&
-	grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
+	test_grep "d1|main|cmd_name|.*|version (_run_dashed_/_run_git_alias_/version)" actual &&
+	test_grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
 '
 
 test_expect_success 'expect def_params during shell alias expansion' '
@@ -456,25 +456,25 @@ test_expect_success 'expect def_params during shell alias expansion' '
 	perl "$TEST_DIRECTORY/t0211/scrub_perf.perl" <prop.perf >actual &&
 
 	# "git xxx" is first mapped to "git-xxx" and the child will fail.
-	grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_)" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_)" actual &&
 
 	# We unpeel that and substitute "git version" for "git xxx" (as a
 	# shell command.  Another cmd_name event is emitted as we unpeel.
-	grep "d0|main|cmd_name|.*|_run_shell_alias_ (_run_dashed_/_run_shell_alias_)" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_shell_alias_ (_run_dashed_/_run_shell_alias_)" actual &&
 
 	# These def_param events could be associated with either of the
 	# above cmd_name events.  It does not matter.
-	grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
+	test_grep "d0|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
 
 	# We get the following only because we used a git command for the
 	# shell command. In general, it could have been a shell script and
 	# we would see nothing.
 	#
 	# The child knows the cmd_name hierarchy so it includes it.
-	grep "d1|main|cmd_name|.*|version (_run_dashed_/_run_shell_alias_/version)" actual &&
-	grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
+	test_grep "d1|main|cmd_name|.*|version (_run_dashed_/_run_shell_alias_/version)" actual &&
+	test_grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
 '
 
 test_expect_success 'expect def_params during nested git alias expansion' '
@@ -496,33 +496,33 @@ test_expect_success 'expect def_params during nested git alias expansion' '
 
 	# "git xxx" is first mapped to "git-xxx" and try to spawn "git-xxx"
 	# and the child will fail.
-	grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_)" actual &&
-	grep "d0|main|child_start|.*|.* class:dashed argv:\[git-xxx\]" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_)" actual &&
+	test_grep "d0|main|child_start|.*|.* class:dashed argv:\[git-xxx\]" actual &&
 
 	# We unpeel that and substitute "yyy" into "xxx" (giving "git yyy")
 	# and spawn "git-yyy" and the child will fail.
-	grep "d0|main|alias|.*|alias:xxx argv:\[yyy\]" actual &&
-	grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_/_run_dashed_)" actual &&
-	grep "d0|main|child_start|.*|.* class:dashed argv:\[git-yyy\]" actual &&
+	test_grep "d0|main|alias|.*|alias:xxx argv:\[yyy\]" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_dashed_ (_run_dashed_/_run_dashed_)" actual &&
+	test_grep "d0|main|child_start|.*|.* class:dashed argv:\[git-yyy\]" actual &&
 
 	# We unpeel that and substitute "version" into "xxx" (giving
 	# "git version") and update the cmd_name event.
-	grep "d0|main|alias|.*|alias:yyy argv:\[version\]" actual &&
-	grep "d0|main|cmd_name|.*|_run_git_alias_ (_run_dashed_/_run_dashed_/_run_git_alias_)" actual &&
+	test_grep "d0|main|alias|.*|alias:yyy argv:\[version\]" actual &&
+	test_grep "d0|main|cmd_name|.*|_run_git_alias_ (_run_dashed_/_run_dashed_/_run_git_alias_)" actual &&
 
 	# These def_param events could be associated with any of the
 	# above cmd_name events.  It does not matter.
 	grep "d0|main|def_param|.*|cfg.prop.foo:red" actual >actual.matches &&
-	grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
+	test_grep "d0|main|def_param|.*|ENV_PROP_FOO:blue" actual &&
 
 	# However, we do not want them repeated each time we unpeel.
 	test_line_count = 1 actual.matches &&
 
 	# The "git version" child sees a different cmd_name hierarchy.
 	# Also test the def_param (only for completeness).
-	grep "d1|main|cmd_name|.*|version (_run_dashed_/_run_dashed_/_run_git_alias_/version)" actual &&
-	grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
-	grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
+	test_grep "d1|main|cmd_name|.*|version (_run_dashed_/_run_dashed_/_run_git_alias_/version)" actual &&
+	test_grep "d1|main|def_param|.*|cfg.prop.foo:red" actual &&
+	test_grep "d1|main|def_param|.*|ENV_PROP_FOO:blue" actual
 '
 
 test_done
diff --git a/t/t0212-trace2-event.sh b/t/t0212-trace2-event.sh
index 1211db9f46..f5358a1dd4 100755
--- a/t/t0212-trace2-event.sh
+++ b/t/t0212-trace2-event.sh
@@ -332,7 +332,7 @@ test_expect_success 'unsafe URLs are redacted by default in cmd_start events' '
 
 	GIT_TRACE2_EVENT="$(pwd)/trace.event" \
 		test-tool trace2 300redact_start git clone https://user:pwd@example.com/ clone2 &&
-	! grep user:pwd trace.event
+	test_grep ! user:pwd trace.event
 '
 
 test_expect_success 'unsafe URLs are redacted by default in child_start events' '
@@ -341,7 +341,7 @@ test_expect_success 'unsafe URLs are redacted by default in child_start events'
 
 	GIT_TRACE2_EVENT="$(pwd)/trace.event" \
 		test-tool trace2 301redact_child_start git clone https://user:pwd@example.com/ clone2 &&
-	! grep user:pwd trace.event
+	test_grep ! user:pwd trace.event
 '
 
 test_expect_success 'unsafe URLs are redacted by default in exec events' '
@@ -350,7 +350,7 @@ test_expect_success 'unsafe URLs are redacted by default in exec events' '
 
 	GIT_TRACE2_EVENT="$(pwd)/trace.event" \
 		test-tool trace2 302redact_exec git clone https://user:pwd@example.com/ clone2 &&
-	! grep user:pwd trace.event
+	test_grep ! user:pwd trace.event
 '
 
 test_expect_success 'unsafe URLs are redacted by default in def_param events' '
@@ -359,7 +359,7 @@ test_expect_success 'unsafe URLs are redacted by default in def_param events' '
 
 	GIT_TRACE2_EVENT="$(pwd)/trace.event" \
 		test-tool trace2 303redact_def_param url https://user:pwd@example.com/ &&
-	! grep user:pwd trace.event
+	test_grep ! user:pwd trace.event
 '
 
 test_done
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
index 64ead1571a..ea11cdb4dc 100755
--- a/t/t0300-credentials.sh
+++ b/t/t0300-credentials.sh
@@ -1014,7 +1014,7 @@ test_expect_success 'credential config with partial URLs' '
 	do
 		git -c credential.$partial.helper=yep \
 			credential fill <stdin >stdout &&
-		grep yep stdout ||
+		test_grep yep stdout ||
 		return 1
 	done &&
 
@@ -1030,7 +1030,7 @@ test_expect_success 'credential config with partial URLs' '
 	do
 		git -c credential.$partial.helper=yep \
 			credential fill <stdin >stdout &&
-		! grep yep stdout ||
+		test_grep ! yep stdout ||
 		return 1
 	done &&
 
diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index 52e19728a3..afa890c470 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -206,7 +206,7 @@ test_expect_success 'fetching of missing objects' '
 	git -C repo cat-file -p "$HASH" 2>err &&
 
 	# Ensure that no spurious FETCH_HEAD messages are written
-	! grep FETCH_HEAD err &&
+	test_grep ! FETCH_HEAD err &&
 
 	# Ensure that the .promisor file is written, and check that its
 	# associated packfile contains the object
@@ -214,7 +214,7 @@ test_expect_success 'fetching of missing objects' '
 	test_line_count = 1 promisorlist &&
 	IDX=$(sed "s/promisor$/idx/" promisorlist) &&
 	git verify-pack --verbose "$IDX" >out &&
-	grep "$HASH" out
+	test_grep "$HASH" out
 '
 
 test_expect_success 'fetching of a promised object that promisor remote no longer has' '
@@ -228,7 +228,7 @@ test_expect_success 'fetching of a promised object that promisor remote no longe
 
 	rm -rf unreliable-server/.git/objects/* &&
 	test_must_fail git -C unreliable-client checkout HEAD 2>err &&
-	grep "could not fetch.*from promisor remote" err
+	test_grep "could not fetch.*from promisor remote" err
 '
 
 test_expect_success 'fetching of missing objects works with ref-in-want enabled' '
@@ -240,7 +240,7 @@ test_expect_success 'fetching of missing objects works with ref-in-want enabled'
 	rm -rf repo/.git/objects/* &&
 	rm -f trace &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C repo cat-file -p "$HASH" &&
-	grep "fetch< fetch=.*ref-in-want" trace
+	test_grep "fetch< fetch=.*ref-in-want" trace
 '
 
 test_expect_success 'fetching from another promisor remote' '
@@ -263,7 +263,7 @@ test_expect_success 'fetching from another promisor remote' '
 	test_line_count = 1 promisorlist &&
 	IDX=$(sed "s/promisor$/idx/" promisorlist) &&
 	git verify-pack --verbose "$IDX" >out &&
-	grep "$HASH2" out
+	test_grep "$HASH2" out
 '
 
 test_expect_success 'fetching with --filter configures a promisor remote' '
@@ -286,7 +286,7 @@ test_expect_success 'fetching with --filter configures a promisor remote' '
 	test_line_count = 1 promisorlist &&
 	IDX=$(sed "s/promisor$/idx/" promisorlist) &&
 	git verify-pack --verbose "$IDX" >out &&
-	grep "$HASH3" out
+	test_grep "$HASH3" out
 '
 
 test_expect_success 'fetching of missing blobs works' '
@@ -327,8 +327,8 @@ test_expect_success 'fetching of missing trees does not fetch blobs' '
 
 	# Ensure that the tree, but not the blob, is fetched
 	git -C repo rev-list --objects --missing=print $(cat treehash) >objects &&
-	grep "^$(cat treehash)" objects &&
-	grep "^[?]$(cat blobhash)" objects
+	test_grep "^$(cat treehash)" objects &&
+	test_grep "^[?]$(cat blobhash)" objects
 '
 
 test_expect_success 'rev-list stops traversal at missing and promised commit' '
@@ -343,8 +343,8 @@ test_expect_success 'rev-list stops traversal at missing and promised commit' '
 	git -C repo config core.repositoryformatversion 1 &&
 	git -C repo config extensions.partialclone "arbitrary string" &&
 	git -C repo rev-list --exclude-promisor-objects --objects bar >out &&
-	grep $(git -C repo rev-parse bar) out &&
-	! grep $FOO out
+	test_grep $(git -C repo rev-parse bar) out &&
+	test_grep ! $FOO out
 '
 
 test_expect_success 'missing tree objects with --missing=allow-promisor and --exclude-promisor-objects' '
@@ -413,10 +413,10 @@ test_expect_success 'rev-list stops traversal at missing and promised tree' '
 	git -C repo config core.repositoryformatversion 1 &&
 	git -C repo config extensions.partialclone "arbitrary string" &&
 	git -C repo rev-list --exclude-promisor-objects --objects HEAD >out &&
-	grep $(git -C repo rev-parse foo) out &&
-	! grep $TREE out &&
-	grep $(git -C repo rev-parse HEAD) out &&
-	! grep $TREE2 out
+	test_grep $(git -C repo rev-parse foo) out &&
+	test_grep ! $TREE out &&
+	test_grep $(git -C repo rev-parse HEAD) out &&
+	test_grep ! $TREE2 out
 '
 
 test_expect_success 'rev-list stops traversal at missing and promised blob' '
@@ -432,8 +432,8 @@ test_expect_success 'rev-list stops traversal at missing and promised blob' '
 	git -C repo config core.repositoryformatversion 1 &&
 	git -C repo config extensions.partialclone "arbitrary string" &&
 	git -C repo rev-list --exclude-promisor-objects --objects HEAD >out &&
-	grep $(git -C repo rev-parse HEAD) out &&
-	! grep $BLOB out
+	test_grep $(git -C repo rev-parse HEAD) out &&
+	test_grep ! $BLOB out
 '
 
 test_expect_success 'rev-list stops traversal at promisor commit, tree, and blob' '
@@ -451,10 +451,10 @@ test_expect_success 'rev-list stops traversal at promisor commit, tree, and blob
 	git -C repo config core.repositoryformatversion 1 &&
 	git -C repo config extensions.partialclone "arbitrary string" &&
 	git -C repo rev-list --exclude-promisor-objects --objects HEAD >out &&
-	! grep $COMMIT out &&
-	! grep $TREE out &&
-	! grep $BLOB out &&
-	grep $(git -C repo rev-parse bar) out  # sanity check that some walking was done
+	test_grep ! $COMMIT out &&
+	test_grep ! $TREE out &&
+	test_grep ! $BLOB out &&
+	test_grep $(git -C repo rev-parse bar) out  # sanity check that some walking was done
 '
 
 test_expect_success 'rev-list dies for missing objects on cmd line' '
@@ -523,10 +523,10 @@ test_expect_success 'gc repacks promisor objects separately from non-promisor ob
 	test_line_count = 1 promisorlist &&
 	PROMISOR_PACKFILE=$(sed "s/.promisor/.pack/" <promisorlist) &&
 	git verify-pack $PROMISOR_PACKFILE -v >out &&
-	grep "$TREE_ONE" out &&
-	grep "$TREE_TWO" out &&
-	! grep "$(git -C repo rev-parse one)" out &&
-	! grep "$(git -C repo rev-parse two)" out &&
+	test_grep "$TREE_ONE" out &&
+	test_grep "$TREE_TWO" out &&
+	test_grep ! "$(git -C repo rev-parse one)" out &&
+	test_grep ! "$(git -C repo rev-parse two)" out &&
 
 	# Remove the promisor packfile and associated files
 	rm $(sed "s/.promisor//" <promisorlist).* &&
@@ -536,10 +536,10 @@ test_expect_success 'gc repacks promisor objects separately from non-promisor ob
 	ls repo/.git/objects/pack/pack-*.pack >packlist &&
 	test_line_count = 1 packlist &&
 	git verify-pack repo/.git/objects/pack/pack-*.pack -v >out &&
-	grep "$(git -C repo rev-parse one)" out &&
-	grep "$(git -C repo rev-parse two)" out &&
-	! grep "$TREE_ONE" out &&
-	! grep "$TREE_TWO" out
+	test_grep "$(git -C repo rev-parse one)" out &&
+	test_grep "$(git -C repo rev-parse two)" out &&
+	test_grep ! "$TREE_ONE" out &&
+	test_grep ! "$TREE_TWO" out
 '
 
 test_expect_success 'gc does not repack promisor objects if there are none' '
@@ -616,8 +616,8 @@ test_expect_success 'gc stops traversal when a missing but promised object is re
 	ls repo/.git/objects/pack/pack-*.pack >packlist &&
 	test_line_count = 1 packlist &&
 	git verify-pack repo/.git/objects/pack/pack-*.pack -v >out &&
-	grep "$(git -C repo rev-parse HEAD)" out &&
-	! grep "$TREE_HASH" out
+	test_grep "$(git -C repo rev-parse HEAD)" out &&
+	test_grep ! "$TREE_HASH" out
 '
 
 test_expect_success 'do not fetch when checking existence of tree we construct ourselves' '
@@ -647,10 +647,10 @@ test_expect_success 'exact rename does not need to fetch the blob lazily' '
 
 	git clone --filter=blob:none --bare "file://$(pwd)/repo" partial.git &&
 	git -C partial.git rev-list --objects --missing=print HEAD >out &&
-	grep "[?]$FILE_HASH" out &&
+	test_grep "[?]$FILE_HASH" out &&
 	git -C partial.git log --follow -- new-file.txt &&
 	git -C partial.git rev-list --objects --missing=print HEAD >out &&
-	grep "[?]$FILE_HASH" out
+	test_grep "[?]$FILE_HASH" out
 '
 
 test_expect_success 'lazy-fetch when accessing object not in the_repository' '
@@ -665,7 +665,7 @@ test_expect_success 'lazy-fetch when accessing object not in the_repository' '
 
 	# Sanity check that the file is missing
 	git -C partial.git rev-list --objects --missing=print HEAD >out &&
-	grep "[?]$FILE_HASH" out &&
+	test_grep "[?]$FILE_HASH" out &&
 
 	# The no-lazy-fetch mechanism prevents Git from fetching
 	test_must_fail env GIT_NO_LAZY_FETCH=1 \
@@ -680,7 +680,7 @@ test_expect_success 'lazy-fetch when accessing object not in the_repository' '
 
 	# Sanity check that the file is still missing
 	git -C partial.git rev-list --objects --missing=print HEAD >out &&
-	grep "[?]$FILE_HASH" out &&
+	test_grep "[?]$FILE_HASH" out &&
 
 	git -C full cat-file -s "$FILE_HASH" >expect &&
 	test-tool partial-clone object-info partial.git "$FILE_HASH" >actual &&
@@ -688,7 +688,7 @@ test_expect_success 'lazy-fetch when accessing object not in the_repository' '
 
 	# Sanity check that the file is now present
 	git -C partial.git rev-list --objects --missing=print HEAD >out &&
-	! grep "[?]$FILE_HASH" out
+	test_grep ! "[?]$FILE_HASH" out
 '
 
 test_expect_success 'push should not fetch new commit objects' '
@@ -705,9 +705,9 @@ test_expect_success 'push should not fetch new commit objects' '
 	COMMIT=$(git -C server rev-parse server2) &&
 
 	test_must_fail git -C client push 2>err &&
-	grep "fetch first" err &&
+	test_grep "fetch first" err &&
 	git -C client rev-list --objects --missing=print "$COMMIT" >objects &&
-	grep "^[?]$COMMIT" objects
+	test_grep "^[?]$COMMIT" objects
 '
 
 test_expect_success 'setup for promisor.quiet tests' '
@@ -728,7 +728,7 @@ test_expect_success TTY 'promisor.quiet=false shows progress messages' '
 	test_terminal git -C repo cat-file -p foo:foo.t 2>err &&
 
 	# Ensure that progress messages are written
-	grep "Receiving objects" err
+	test_grep "Receiving objects" err
 '
 
 test_expect_success TTY 'promisor.quiet=true does not show progress messages' '
@@ -739,7 +739,7 @@ test_expect_success TTY 'promisor.quiet=true does not show progress messages' '
 	test_terminal git -C repo cat-file -p foo:foo.t 2>err &&
 
 	# Ensure that no progress messages are written
-	! grep "Receiving objects" err
+	test_grep ! "Receiving objects" err
 '
 
 test_expect_success TTY 'promisor.quiet=unconfigured shows progress messages' '
@@ -749,7 +749,7 @@ test_expect_success TTY 'promisor.quiet=unconfigured shows progress messages' '
 	test_terminal git -C repo cat-file -p foo:foo.t 2>err &&
 
 	# Ensure that progress messages are written
-	grep "Receiving objects" err
+	test_grep "Receiving objects" err
 '
 
 . "$TEST_DIRECTORY"/lib-httpd.sh
@@ -776,7 +776,7 @@ test_expect_success 'fetching of missing objects from an HTTP server' '
 	test_line_count = 1 promisorlist &&
 	IDX=$(sed "s/promisor$/idx/" promisorlist) &&
 	git verify-pack --verbose "$IDX" >out &&
-	grep "$HASH" out
+	test_grep "$HASH" out
 '
 
 # DO NOT add non-httpd-specific tests here, because the last part of this
diff --git a/t/t0450-txt-doc-vs-help.sh b/t/t0450-txt-doc-vs-help.sh
index 822b0d55a5..e7ba967223 100755
--- a/t/t0450-txt-doc-vs-help.sh
+++ b/t/t0450-txt-doc-vs-help.sh
@@ -87,7 +87,7 @@ do
 	# -h output assertions
 	test_expect_success "$builtin -h output has no \t" '
 		h2s="$(help_to_synopsis "$builtin")" &&
-		! grep "$HT" "$h2s"
+		test_grep ! "$HT" "$h2s"
 	'
 
 	test_expect_success "$builtin -h output has dashed labels" '
diff --git a/t/t0500-progress-display.sh b/t/t0500-progress-display.sh
index d1a498a216..fe2232cce0 100755
--- a/t/t0500-progress-display.sh
+++ b/t/t0500-progress-display.sh
@@ -320,8 +320,8 @@ test_expect_success 'progress generates traces' '
 
 	# t0212/parse_events.perl intentionally omits regions and data.
 	test_region progress "Working hard" trace.event &&
-	grep "\"key\":\"total_objects\",\"value\":\"40\"" trace.event &&
-	grep "\"key\":\"total_bytes\",\"value\":\"409600\"" trace.event
+	test_grep "\"key\":\"total_objects\",\"value\":\"40\"" trace.event &&
+	test_grep "\"key\":\"total_bytes\",\"value\":\"409600\"" trace.event
 '
 
 test_expect_success 'progress generates traces: stop / start' '
@@ -344,8 +344,8 @@ test_expect_success 'progress generates traces: start without stop' '
 	LSAN_OPTIONS=detect_leaks=0 \
 	test-tool progress \
 		<in 2>stderr &&
-	grep region_enter.*progress trace-start.event &&
-	! grep region_leave.*progress trace-start.event
+	test_grep region_enter.*progress trace-start.event &&
+	test_grep ! region_leave.*progress trace-start.event
 '
 
 test_expect_success 'progress generates traces: stop without start' '
@@ -355,8 +355,8 @@ test_expect_success 'progress generates traces: stop without start' '
 
 	GIT_TRACE2_EVENT="$PWD/trace-stop.event" test-tool progress \
 		<in 2>stderr &&
-	! grep region_enter.*progress trace-stop.event &&
-	! grep region_leave.*progress trace-stop.event
+	test_grep ! region_enter.*progress trace-stop.event &&
+	test_grep ! region_leave.*progress trace-stop.event
 '
 
 test_expect_success 'progress generates traces: start with active progress bar (no stops)' '
@@ -369,9 +369,9 @@ test_expect_success 'progress generates traces: start with active progress bar (
 	LSAN_OPTIONS=detect_leaks=0 \
 	test-tool progress \
 		<in 2>stderr &&
-	grep region_enter.*progress.*One trace-2start.event &&
-	grep region_enter.*progress.*Two trace-2start.event &&
-	! grep region_leave trace-2start.event
+	test_grep region_enter.*progress.*One trace-2start.event &&
+	test_grep region_enter.*progress.*Two trace-2start.event &&
+	test_grep ! region_leave trace-2start.event
 '
 
 test_done
diff --git a/t/t0610-reftable-basics.sh b/t/t0610-reftable-basics.sh
index e19e036898..2f4c5e2a1b 100755
--- a/t/t0610-reftable-basics.sh
+++ b/t/t0610-reftable-basics.sh
@@ -776,11 +776,11 @@ test_expect_success 'reflog: can delete separate reflog entries' '
 		test_commit file3 &&
 		test_commit file4 &&
 		git reflog >actual &&
-		grep file3 actual &&
+		test_grep file3 actual &&
 
 		git reflog delete HEAD@{1} &&
 		git reflog >actual &&
-		! grep file3 actual
+		test_grep ! file3 actual
 	)
 '
 
@@ -902,8 +902,8 @@ test_expect_success 'reflog: garbage collection deletes reflog entries' '
 		done &&
 		git reflog refs/heads/main >actual &&
 		test_line_count = 10 actual &&
-		grep "commit (initial): number 1" actual &&
-		grep "commit: number 10" actual &&
+		test_grep "commit (initial): number 1" actual &&
+		test_grep "commit: number 10" actual &&
 
 		git gc &&
 		git reflog refs/heads/main >actual &&
diff --git a/t/t1004-read-tree-m-u-wf.sh b/t/t1004-read-tree-m-u-wf.sh
index 11bf10424f..70ba3eea4d 100755
--- a/t/t1004-read-tree-m-u-wf.sh
+++ b/t/t1004-read-tree-m-u-wf.sh
@@ -142,8 +142,8 @@ test_expect_success '3-way not overwriting local changes (our side)' '
 
 	echo >>file1 "local changes" &&
 	read_tree_u_must_succeed -m -u branch-point side-a side-b &&
-	grep "new line to be kept" file1 &&
-	grep "local changes" file1
+	test_grep "new line to be kept" file1 &&
+	test_grep "local changes" file1
 
 '
 
@@ -156,8 +156,8 @@ test_expect_success '3-way not overwriting local changes (their side)' '
 
 	echo >>file2 "local changes" &&
 	read_tree_u_must_fail -m -u branch-point side-a side-b &&
-	! grep "new line to be kept" file2 &&
-	grep "local changes" file2
+	test_grep ! "new line to be kept" file2 &&
+	test_grep "local changes" file2
 
 '
 
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index 8e2c52652c..762c77c351 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -696,8 +696,8 @@ test_expect_success '%(deltabase) reports packed delta bases' '
 	git repack -ad &&
 	git cat-file --batch-check="%(deltabase)" <blobs >actual &&
 	{
-		grep "$(git rev-parse HEAD:foo)" actual ||
-		grep "$(git rev-parse HEAD:foo-plus)" actual
+		test_grep "$(git rev-parse HEAD:foo)" actual ||
+		test_grep "$(git rev-parse HEAD:foo-plus)" actual
 	}
 '
 
@@ -826,7 +826,7 @@ test_expect_success 'cat-file -t and -s on corrupt loose object' '
 		# Swap the two to corrupt the repository
 		mv -f "$other_path" "$empty_path" &&
 		test_must_fail git fsck 2>err.fsck &&
-		grep "hash-path mismatch" err.fsck &&
+		test_grep "hash-path mismatch" err.fsck &&
 
 		# confirm that cat-file is reading the new swapped-in
 		# blob...
@@ -1318,37 +1318,37 @@ test_expect_success 'cat-file --batch-all-objects --batch-check ignores replace'
 test_expect_success 'batch-command empty command' '
 	echo "" >cmd &&
 	test_expect_code 128 git cat-file --batch-command <cmd 2>err &&
-	grep "^fatal:.*empty command in input.*" err
+	test_grep "^fatal:.*empty command in input.*" err
 '
 
 test_expect_success 'batch-command whitespace before command' '
 	echo " info deadbeef" >cmd &&
 	test_expect_code 128 git cat-file --batch-command <cmd 2>err &&
-	grep "^fatal:.*whitespace before command.*" err
+	test_grep "^fatal:.*whitespace before command.*" err
 '
 
 test_expect_success 'batch-command unknown command' '
 	echo unknown_command >cmd &&
 	test_expect_code 128 git cat-file --batch-command <cmd 2>err &&
-	grep "^fatal:.*unknown command.*" err
+	test_grep "^fatal:.*unknown command.*" err
 '
 
 test_expect_success 'batch-command missing arguments' '
 	echo "info" >cmd &&
 	test_expect_code 128 git cat-file --batch-command <cmd 2>err &&
-	grep "^fatal:.*info requires arguments.*" err
+	test_grep "^fatal:.*info requires arguments.*" err
 '
 
 test_expect_success 'batch-command flush with arguments' '
 	echo "flush arg" >cmd &&
 	test_expect_code 128 git cat-file --batch-command --buffer <cmd 2>err &&
-	grep "^fatal:.*flush takes no arguments.*" err
+	test_grep "^fatal:.*flush takes no arguments.*" err
 '
 
 test_expect_success 'batch-command flush without --buffer' '
 	echo "flush" >cmd &&
 	test_expect_code 128 git cat-file --batch-command <cmd 2>err &&
-	grep "^fatal:.*flush is only for --buffer mode.*" err
+	test_grep "^fatal:.*flush is only for --buffer mode.*" err
 '
 
 perl_script='
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index de076293b6..4782a6246a 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -202,7 +202,7 @@ done
 test_expect_success 'too-short tree' '
 	echo abc >malformed-tree &&
 	test_must_fail git hash-object -t tree malformed-tree 2>err &&
-	grep "too-short tree object" err
+	test_grep "too-short tree object" err
 '
 
 test_expect_success PERL_TEST_HELPERS 'malformed mode in tree' '
@@ -210,7 +210,7 @@ test_expect_success PERL_TEST_HELPERS 'malformed mode in tree' '
 	bin_oid=$(echo $hex_oid | hex2oct) &&
 	printf "9100644 \0$bin_oid" >tree-with-malformed-mode &&
 	test_must_fail git hash-object -t tree tree-with-malformed-mode 2>err &&
-	grep "malformed mode in tree entry" err
+	test_grep "malformed mode in tree entry" err
 '
 
 test_expect_success PERL_TEST_HELPERS 'empty filename in tree' '
@@ -218,7 +218,7 @@ test_expect_success PERL_TEST_HELPERS 'empty filename in tree' '
 	bin_oid=$(echo $hex_oid | hex2oct) &&
 	printf "100644 \0$bin_oid" >tree-with-empty-filename &&
 	test_must_fail git hash-object -t tree tree-with-empty-filename 2>err &&
-	grep "empty filename in tree entry" err
+	test_grep "empty filename in tree entry" err
 '
 
 test_expect_success PERL_TEST_HELPERS 'duplicate filename in tree' '
@@ -229,7 +229,7 @@ test_expect_success PERL_TEST_HELPERS 'duplicate filename in tree' '
 		printf "100644 file\0$bin_oid"
 	} >tree-with-duplicate-filename &&
 	test_must_fail git hash-object -t tree tree-with-duplicate-filename 2>err &&
-	grep "duplicateEntries" err
+	test_grep "duplicateEntries" err
 '
 
 test_expect_success 'corrupt commit' '
diff --git a/t/t1011-read-tree-sparse-checkout.sh b/t/t1011-read-tree-sparse-checkout.sh
index 742f0fa909..f6a5dbe519 100755
--- a/t/t1011-read-tree-sparse-checkout.sh
+++ b/t/t1011-read-tree-sparse-checkout.sh
@@ -196,7 +196,7 @@ test_expect_success 'read-tree will not throw away dirty changes, non-sparse' '
 	echo dirty >init.t &&
 	read_tree_u_must_fail -m -u HEAD^ &&
 	test_path_is_file init.t &&
-	grep -q dirty init.t
+	test_grep dirty init.t
 '
 
 test_expect_success 'read-tree will not throw away dirty changes, sparse' '
@@ -207,7 +207,7 @@ test_expect_success 'read-tree will not throw away dirty changes, sparse' '
 	echo sub/added >.git/info/sparse-checkout &&
 	read_tree_u_must_fail -m -u HEAD^ &&
 	test_path_is_file init.t &&
-	grep -q dirty init.t
+	test_grep dirty init.t
 '
 
 test_expect_success 'read-tree updates worktree, dirty case' '
@@ -215,7 +215,7 @@ test_expect_success 'read-tree updates worktree, dirty case' '
 	git checkout -f top &&
 	echo dirty >init.t &&
 	read_tree_u_must_fail -m -u HEAD^ &&
-	grep -q dirty init.t &&
+	test_grep dirty init.t &&
 	rm init.t
 '
 
@@ -224,7 +224,7 @@ test_expect_success 'read-tree removes worktree, dirty case' '
 	git checkout -f top &&
 	echo dirty >added &&
 	read_tree_u_must_succeed -m -u HEAD^ &&
-	grep -q dirty added
+	test_grep dirty added
 '
 
 test_expect_success 'read-tree adds to worktree, absent case' '
@@ -240,7 +240,7 @@ test_expect_success 'read-tree adds to worktree, dirty case' '
 	mkdir sub &&
 	echo dirty >sub/added &&
 	read_tree_u_must_succeed -u -m HEAD^ &&
-	grep -q dirty sub/added
+	test_grep dirty sub/added
 '
 
 test_expect_success 'index removal and worktree narrowing at the same time' '
diff --git a/t/t1050-large.sh b/t/t1050-large.sh
index 7d40d08521..d295c265c7 100755
--- a/t/t1050-large.sh
+++ b/t/t1050-large.sh
@@ -8,7 +8,7 @@ test_description='adding and checking out large blobs'
 test_expect_success 'core.bigFileThreshold must be non-negative' '
 	: >input &&
 	test_must_fail git -c core.bigFileThreshold=-1 hash-object input >out 2>err &&
-	grep "bad numeric config value" err &&
+	test_grep "bad numeric config value" err &&
 	test_must_be_empty out
 '
 
@@ -148,12 +148,12 @@ test_expect_success 'diff --stat' '
 
 test_expect_success 'diff' '
 	git diff HEAD^ HEAD >actual &&
-	grep "Binary files.*differ" actual
+	test_grep "Binary files.*differ" actual
 '
 
 test_expect_success 'diff --cached' '
 	git diff --cached HEAD^ >actual &&
-	grep "Binary files.*differ" actual
+	test_grep "Binary files.*differ" actual
 '
 
 test_expect_success 'hash-object' '
diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index cd0aed9975..74b1761e0c 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -129,7 +129,7 @@ test_expect_success 'switching to cone mode with non-cone mode patterns' '
 		git sparse-checkout add dir &&
 		git config --worktree core.sparseCheckoutCone true &&
 		test_must_fail git sparse-checkout add dir 2>err &&
-		grep "existing sparse-checkout patterns do not use cone mode" err
+		test_grep "existing sparse-checkout patterns do not use cone mode" err
 	)
 '
 
@@ -803,7 +803,7 @@ test_expect_success 'cone mode clears ignored subdirectories' '
 	# When an untracked file is in the way, all untracked files
 	# (even ignored files) are preserved.
 	git -C repo sparse-checkout set folder1 2>err &&
-	grep "contains untracked files" err &&
+	test_grep "contains untracked files" err &&
 	test_path_is_file repo/deep/deeper2/ignored.o &&
 	test_path_is_file repo/deep/deeper2/untracked &&
 
@@ -882,8 +882,8 @@ test_expect_success 'malformed cone-mode patterns' '
 	# of using the cone-mode translation to a set of directories.
 	git -C repo sparse-checkout list >actual 2>err &&
 	test_cmp repo/.git/info/sparse-checkout actual &&
-	grep "warning: your sparse-checkout file may have issues: pattern .* is repeated" err &&
-	grep "warning: disabling cone pattern matching" err
+	test_grep "warning: your sparse-checkout file may have issues: pattern .* is repeated" err &&
+	test_grep "warning: disabling cone pattern matching" err
 '
 
 test_expect_success 'set from subdir pays attention to prefix' '
@@ -917,34 +917,34 @@ test_expect_success 'set from subdir in non-cone mode throws an error' '
 	git -C repo sparse-checkout disable &&
 	test_must_fail git -C repo/deep sparse-checkout set --no-cone deeper2 ../folder1 2>error &&
 
-	grep "run from the toplevel directory in non-cone mode" error
+	test_grep "run from the toplevel directory in non-cone mode" error
 '
 
 test_expect_success 'set from subdir in non-cone mode throws an error' '
 	git -C repo sparse-checkout set --no-cone deep/deeper2 &&
 	test_must_fail git -C repo/deep sparse-checkout add deeper1/deepest ../folder1 2>error &&
 
-	grep "run from the toplevel directory in non-cone mode" error
+	test_grep "run from the toplevel directory in non-cone mode" error
 '
 
 test_expect_success 'by default, cone mode will error out when passed files' '
 	git -C repo sparse-checkout reapply --cone &&
 	test_must_fail git -C repo sparse-checkout add .gitignore 2>error &&
 
-	grep ".gitignore.*is not a directory" error
+	test_grep ".gitignore.*is not a directory" error
 '
 
 test_expect_success 'error on mistyped command line options' '
 	test_must_fail git -C repo sparse-checkout add --sikp-checks .gitignore 2>error &&
 
-	grep "unknown option.*sikp-checks" error
+	test_grep "unknown option.*sikp-checks" error
 '
 
 test_expect_success 'by default, non-cone mode will warn on individual files' '
 	git -C repo sparse-checkout reapply --no-cone &&
 	git -C repo sparse-checkout add .gitignore 2>warning &&
 
-	grep "pass a leading slash before paths.*if you want a single file" warning
+	test_grep "pass a leading slash before paths.*if you want a single file" warning
 '
 
 test_expect_success 'setup bare repo' '
@@ -1108,11 +1108,11 @@ test_expect_success 'clean' '
 	touch repo/folder1/extra/inside/file &&
 
 	test_must_fail git -C repo sparse-checkout clean 2>err &&
-	grep "refusing to clean" err &&
+	test_grep "refusing to clean" err &&
 
 	git -C repo config clean.requireForce true &&
 	test_must_fail git -C repo sparse-checkout clean 2>err &&
-	grep "refusing to clean" err &&
+	test_grep "refusing to clean" err &&
 
 	cat >expect <<-\EOF &&
 	Would remove deep/deeper2/
@@ -1255,7 +1255,7 @@ test_expect_success 'sparse-checkout operations with merge conflicts' '
 		test_must_fail git merge -m "will-conflict" right &&
 
 		test_must_fail git sparse-checkout clean -f 2>err &&
-		grep "failed to convert index to a sparse index" err &&
+		test_grep "failed to convert index to a sparse index" err &&
 
 		echo merged >folder1/even/more/dirs/file &&
 		git add --sparse folder1 &&
diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index d98cb4ac11..b5b5e615e7 100755
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -454,10 +454,10 @@ test_expect_success 'add outside sparse cone' '
 	run_on_sparse ../edit-contents folder1/a &&
 	run_on_sparse ../edit-contents folder1/newfile &&
 	test_sparse_match test_must_fail git add folder1/a &&
-	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
 	test_sparse_match test_must_fail git add folder1/newfile &&
-	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/newfile
 '
 
@@ -509,13 +509,13 @@ test_expect_success 'status/add: outside sparse cone' '
 
 	# Adding the path outside of the sparse-checkout cone should fail.
 	test_sparse_match test_must_fail git add folder1/a &&
-	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
 	test_all_match git add --refresh folder1/a &&
 	test_must_be_empty sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
 	test_sparse_match test_must_fail git add folder1/new &&
-	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/new &&
 	test_sparse_match git add --sparse folder1/a &&
 	test_sparse_match git add --sparse folder1/new &&
@@ -661,8 +661,8 @@ test_expect_success 'checkout and reset (mixed)' '
 	# in sparse-checkout or sparse-index.
 	git -C full-checkout reset update-folder1 >full-checkout-out &&
 	test_sparse_match git reset update-folder1 &&
-	grep "M	folder1/a" full-checkout-out &&
-	! grep "M	folder1/a" sparse-checkout-out &&
+	test_grep "M	folder1/a" full-checkout-out &&
+	test_grep ! "M	folder1/a" sparse-checkout-out &&
 	run_on_sparse test_path_is_missing folder1
 '
 
@@ -880,8 +880,8 @@ test_expect_success 'update-index with directories' '
 	# update-index will exit silently when provided with a directory name
 	# containing a trailing slash
 	test_all_match git update-index deep/ folder1/ &&
-	grep "Ignoring path deep/" sparse-checkout-err &&
-	grep "Ignoring path folder1/" sparse-checkout-err &&
+	test_grep "Ignoring path deep/" sparse-checkout-err &&
+	test_grep "Ignoring path folder1/" sparse-checkout-err &&
 
 	# When update-index is given a directory name WITHOUT a trailing slash, it will
 	# behave in different ways depending on the status of the directory on disk:
@@ -1067,7 +1067,7 @@ test_expect_success 'merge with conflict outside cone' '
 
 	# 2. Add the file with conflict markers
 	test_sparse_match test_must_fail git add folder1/a &&
-	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder1/a &&
 	test_all_match git add --sparse folder1/a &&
 	test_all_match git status --porcelain=v2 &&
@@ -1076,7 +1076,7 @@ test_expect_success 'merge with conflict outside cone' '
 	#    accept conflict markers as resolved content.
 	run_on_all mv folder2/a folder2/z &&
 	test_sparse_match test_must_fail git add folder2 &&
-	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_sparse_unstaged folder2/z &&
 	test_all_match git add --sparse folder2 &&
 	test_all_match git status --porcelain=v2 &&
@@ -1107,7 +1107,7 @@ test_expect_success 'cherry-pick/rebase with conflict outside cone' '
 		# SKIP_WORKTREE bit from the index entry for folder1/a, we should
 		# warn that this is a problematic add.
 		test_sparse_match test_must_fail git add folder1/a &&
-		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+		test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 		test_sparse_unstaged folder1/a &&
 		test_all_match git add --sparse folder1/a &&
 		test_all_match git status --porcelain=v2 &&
@@ -1119,7 +1119,7 @@ test_expect_success 'cherry-pick/rebase with conflict outside cone' '
 		# existing index entry with the SKIP_WORKTREE bit cleared.
 		run_on_all mv folder2/a folder2/z &&
 		test_sparse_match test_must_fail git add folder2 &&
-		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+		test_grep "Disable or modify the sparsity rules" sparse-checkout-err &&
 		test_sparse_unstaged folder2/z &&
 		test_all_match git add --sparse folder2 &&
 		test_all_match git status --porcelain=v2 &&
@@ -1266,7 +1266,7 @@ test_expect_success 'checkout-index with folders' '
 	run_on_all test_must_fail git checkout-index -f -- folder1/ &&
 	test_cmp full-checkout-err sparse-checkout-err &&
 	! test_cmp full-checkout-err sparse-index-err &&
-	grep "is a sparse directory" sparse-index-err
+	test_grep "is a sparse directory" sparse-index-err
 '
 
 test_expect_success 'checkout-index --all' '
@@ -1374,8 +1374,8 @@ test_expect_success 'submodule handling' '
 	# having a submodule prevents "modules" from collapse
 	test_sparse_match git sparse-checkout set deep/deeper1 &&
 	git -C sparse-index ls-files --sparse --stage >cache &&
-	grep "100644 .*	modules/a" cache &&
-	grep "160000 $(git -C initial-repo rev-parse HEAD) 0	modules/sub" cache
+	test_grep "100644 .*	modules/a" cache &&
+	test_grep "160000 $(git -C initial-repo rev-parse HEAD) 0	modules/sub" cache
 '
 
 test_expect_success 'git apply functionality' '
@@ -1392,7 +1392,7 @@ test_expect_success 'git apply functionality' '
 
 	# Apply a patch to a file outside the sparse definition
 	test_sparse_match test_must_fail git apply ../patch-outside &&
-	grep "No such file or directory" sparse-checkout-err &&
+	test_grep "No such file or directory" sparse-checkout-err &&
 
 	# But it works with --index and --cached
 	test_all_match git apply --index --stat ../patch-outside &&
@@ -2013,9 +2013,9 @@ test_expect_success 'mv directory from out-of-cone to in-cone' '
 	test_all_match git status --porcelain=v2 &&
 	test_sparse_match git ls-files -t &&
 	git -C sparse-checkout ls-files -t >actual &&
-	grep -e "H deep/folder1/0/0/0" actual &&
-	grep -e "H deep/folder1/0/1" actual &&
-	grep -e "H deep/folder1/a" actual &&
+	test_grep -e "H deep/folder1/0/0/0" actual &&
+	test_grep -e "H deep/folder1/0/1" actual &&
+	test_grep -e "H deep/folder1/a" actual &&
 
 	test_all_match git reset --hard &&
 
@@ -2025,8 +2025,8 @@ test_expect_success 'mv directory from out-of-cone to in-cone' '
 	test_sparse_match git status --porcelain=v2 &&
 	test_sparse_match git ls-files -t &&
 	git -C sparse-checkout ls-files -t >actual &&
-	grep -e "H deep/0/0/0" actual &&
-	grep -e "H deep/0/1" actual
+	test_grep -e "H deep/0/0/0" actual &&
+	test_grep -e "H deep/0/1" actual
 '
 
 test_expect_success 'rm pathspec inside sparse definition' '
@@ -2517,7 +2517,7 @@ test_expect_success 'advice.sparseIndexExpanded' '
 	mkdir -p sparse-index/deep/deeper2/deepest &&
 	touch sparse-index/deep/deeper2/deepest/bogus &&
 	git -C sparse-index status 2>err &&
-	grep "The sparse index is expanding to a full index" err &&
+	test_grep "The sparse index is expanding to a full index" err &&
 
 	git -C sparse-index sparse-checkout disable 2>err &&
 	test_line_count = 0 err
diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index 11fc976f3a..b337e25d92 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -800,7 +800,7 @@ test_expect_success 'renaming a section with an overly-long line' '
 		printf "[a] g = h\\n"
 	} >y &&
 	test_must_fail git config ${mode_prefix}rename-section -f y a xyz 2>err &&
-	grep "refusing to work with overly long line in .y. on line 2" err
+	test_grep "refusing to work with overly long line in .y. on line 2" err
 '
 
 cat >> .git/config << EOF
@@ -1615,9 +1615,9 @@ test_expect_success 'git --config-env=key=envvar support' '
 
 test_expect_success 'git --config-env with missing value' '
 	test_must_fail env ENVVAR=value git --config-env 2>error &&
-	grep "no config key given for --config-env" error &&
+	test_grep "no config key given for --config-env" error &&
 	test_must_fail env ENVVAR=value git --config-env config core.name 2>error &&
-	grep "invalid config format: config" error
+	test_grep "invalid config format: config" error
 '
 
 test_expect_success 'git --config-env fails with invalid parameters' '
@@ -2048,7 +2048,7 @@ test_expect_success '--unset last key removes section (except if commented)' '
 	key = true
 	EOF
 	git config ${mode_unset} two.key &&
-	! grep two .git/config &&
+	test_grep ! two .git/config &&
 
 	q_to_tab >.git/config <<-\EOF &&
 	[one]
@@ -2068,7 +2068,7 @@ test_expect_success '--unset last key removes section (except if commented)' '
 	Qkey = true
 	EOF
 	git config ${mode_unset} two.key &&
-	grep two .git/config &&
+	test_grep two .git/config &&
 
 	q_to_tab >.git/config <<-\EOF &&
 	[one]
@@ -2599,7 +2599,7 @@ test_expect_success '--type rejects unknown specifiers' '
 
 test_expect_success '--type=int requires at least one digit' '
 	test_must_fail git config --type int --default m some.key >out 2>error &&
-	grep "bad numeric config value" error &&
+	test_grep "bad numeric config value" error &&
 	test_must_be_empty out
 '
 
@@ -2911,12 +2911,12 @@ test_expect_success 'includeIf.hasconfig:remote.*.url forbids remote url in such
 
 	# test with any Git command
 	test_must_fail git -C hasremoteurlTest status 2>err &&
-	grep "fatal: remote URLs cannot be configured in file directly or indirectly included by includeIf.hasconfig:remote.*.url" err
+	test_grep "fatal: remote URLs cannot be configured in file directly or indirectly included by includeIf.hasconfig:remote.*.url" err
 '
 
 test_expect_success 'negated mode causes failure' '
 	test_must_fail git config --no-get 2>err &&
-	grep "unknown option \`no-get${SQ}" err
+	test_grep "unknown option \`no-get${SQ}" err
 '
 
 test_expect_success 'specifying multiple modes causes failure' '
diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
index f3892578e4..f6115269f9 100755
--- a/t/t1305-config-include.sh
+++ b/t/t1305-config-include.sh
@@ -353,7 +353,7 @@ test_expect_success 'include cycles are detected' '
 	git -C cycle --git-dir=. config include.path cycle &&
 	git config -f cycle/cycle include.path config &&
 	test_must_fail git -C cycle --git-dir=. config --get-all test.value 2>stderr &&
-	grep "exceeded maximum include depth" stderr
+	test_grep "exceeded maximum include depth" stderr
 '
 
 test_expect_success 'onbranch with unborn branch' '
diff --git a/t/t1308-config-set.sh b/t/t1308-config-set.sh
index e0e49053f0..de95161a83 100755
--- a/t/t1308-config-set.sh
+++ b/t/t1308-config-set.sh
@@ -180,7 +180,7 @@ test_expect_success 'find integer if value is non parse-able' '
 
 test_expect_success 'non parse-able integer value during iteration' '
 	check_config expect_code 128 git_config_int lamb.head 2>result &&
-	grep "fatal: bad numeric config value .* in file \.git/config" result
+	test_grep "fatal: bad numeric config value .* in file \.git/config" result
 '
 
 test_expect_success 'find bool value for the entered key' '
@@ -302,7 +302,7 @@ test_expect_success 'proper error on directory "files"' '
 	echo "Error (-1) reading configuration file a-directory." >expect &&
 	mkdir a-directory &&
 	test_expect_code 2 test-tool config configset_get_value foo.bar a-directory 2>output &&
-	grep "^warning:" output &&
+	test_grep "^warning:" output &&
 	grep "^Error" output >actual &&
 	test_cmp expect actual
 '
@@ -312,7 +312,7 @@ test_expect_success POSIXPERM,SANITY 'proper error on non-accessible files' '
 	test_when_finished "chmod +r .git/config" &&
 	echo "Error (-1) reading configuration file .git/config." >expect &&
 	test_expect_code 2 test-tool config configset_get_value foo.bar .git/config 2>output &&
-	grep "^warning:" output &&
+	test_grep "^warning:" output &&
 	grep "^Error" output >actual &&
 	test_cmp expect actual
 '
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index 1015f335e3..7c89071662 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -92,7 +92,7 @@ test_expect_success "deleting current branch adds message to HEAD's log" '
 	git update-ref -m delete-$m -d $m &&
 	test_must_fail git show-ref --verify -q $m &&
 	test-tool ref-store main for-each-reflog-ent HEAD >actual &&
-	grep "delete-$m$" actual
+	test_grep "delete-$m$" actual
 '
 
 test_expect_success "deleting by HEAD adds message to HEAD's log" '
@@ -102,7 +102,7 @@ test_expect_success "deleting by HEAD adds message to HEAD's log" '
 	git update-ref -m delete-by-head -d HEAD &&
 	test_must_fail git show-ref --verify -q $m &&
 	test-tool ref-store main for-each-reflog-ent HEAD >actual &&
-	grep "delete-by-head$" actual
+	test_grep "delete-by-head$" actual
 '
 
 test_expect_success 'update-ref does not create reflogs by default' '
@@ -192,7 +192,7 @@ test_expect_success "move $m (by HEAD)" '
 test_expect_success "delete $m (by HEAD) should remove both packed and loose $m" '
 	test_when_finished "git update-ref -d $m" &&
 	git update-ref -d HEAD $B &&
-	! grep "$m" .git/packed-refs &&
+	! grep "$m" .git/packed-refs && # lint-ok: file may not exist (reftable)
 	test_must_fail git show-ref --verify -q $m
 '
 
@@ -575,103 +575,103 @@ test_expect_success 'stdin works with no input' '
 test_expect_success 'stdin fails on empty line' '
 	echo "" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: empty command in input" err
+	test_grep "fatal: empty command in input" err
 '
 
 test_expect_success 'stdin fails on only whitespace' '
 	echo " " >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: whitespace before command:  " err
+	test_grep "fatal: whitespace before command:  " err
 '
 
 test_expect_success 'stdin fails on leading whitespace' '
 	echo " create $a $m" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: whitespace before command:  create $a $m" err
+	test_grep "fatal: whitespace before command:  create $a $m" err
 '
 
 test_expect_success 'stdin fails on unknown command' '
 	echo "unknown $a" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: unknown command: unknown $a" err
+	test_grep "fatal: unknown command: unknown $a" err
 '
 
 test_expect_success 'stdin fails on unbalanced quotes' '
 	echo "create $a \"main" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: badly quoted argument: \\\"main" err
+	test_grep "fatal: badly quoted argument: \\\"main" err
 '
 
 test_expect_success 'stdin fails on invalid escape' '
 	echo "create $a \"ma\zn\"" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: badly quoted argument: \\\"ma\\\\zn\\\"" err
+	test_grep "fatal: badly quoted argument: \\\"ma\\\\zn\\\"" err
 '
 
 test_expect_success 'stdin fails on junk after quoted argument' '
 	echo "create \"$a\"main" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: unexpected character after quoted argument: \\\"$a\\\"main" err
+	test_grep "fatal: unexpected character after quoted argument: \\\"$a\\\"main" err
 '
 
 test_expect_success 'stdin fails create with no ref' '
 	echo "create " >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: create: missing <ref>" err
+	test_grep "fatal: create: missing <ref>" err
 '
 
 test_expect_success 'stdin fails create with no new value' '
 	echo "create $a" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: create $a: missing <new-oid>" err
+	test_grep "fatal: create $a: missing <new-oid>" err
 '
 
 test_expect_success 'stdin fails create with too many arguments' '
 	echo "create $a $m $m" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: create $a: extra input:  $m" err
+	test_grep "fatal: create $a: extra input:  $m" err
 '
 
 test_expect_success 'stdin fails update with no ref' '
 	echo "update " >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: update: missing <ref>" err
+	test_grep "fatal: update: missing <ref>" err
 '
 
 test_expect_success 'stdin fails update with no new value' '
 	echo "update $a" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: update $a: missing <new-oid>" err
+	test_grep "fatal: update $a: missing <new-oid>" err
 '
 
 test_expect_success 'stdin fails update with too many arguments' '
 	echo "update $a $m $m $m" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: update $a: extra input:  $m" err
+	test_grep "fatal: update $a: extra input:  $m" err
 '
 
 test_expect_success 'stdin fails delete with no ref' '
 	echo "delete " >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: delete: missing <ref>" err
+	test_grep "fatal: delete: missing <ref>" err
 '
 
 test_expect_success 'stdin fails delete with too many arguments' '
 	echo "delete $a $m $m" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: delete $a: extra input:  $m" err
+	test_grep "fatal: delete $a: extra input:  $m" err
 '
 
 test_expect_success 'stdin fails verify with too many arguments' '
 	echo "verify $a $m $m" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: verify $a: extra input:  $m" err
+	test_grep "fatal: verify $a: extra input:  $m" err
 '
 
 test_expect_success 'stdin fails option with unknown name' '
 	echo "option unknown" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: option unknown: unknown" err
+	test_grep "fatal: option unknown: unknown" err
 '
 
 test_expect_success 'stdin fails with duplicate refs' '
@@ -759,28 +759,28 @@ test_expect_success 'stdin create ref works with path with space to blob' '
 test_expect_success 'stdin update ref fails with wrong old value' '
 	echo "update $c $m $m~1" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
+	test_grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
 test_expect_success 'stdin update ref fails with bad old value' '
 	echo "update $c $m does-not-exist" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: update $c: invalid <old-oid>: does-not-exist" err &&
+	test_grep "fatal: update $c: invalid <old-oid>: does-not-exist" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
 test_expect_success 'stdin create ref fails with bad new value' '
 	echo "create $c does-not-exist" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: create $c: invalid <new-oid>: does-not-exist" err &&
+	test_grep "fatal: create $c: invalid <new-oid>: does-not-exist" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
 test_expect_success 'stdin create ref fails with zero new value' '
 	echo "create $c " >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: create $c: zero <new-oid>" err &&
+	test_grep "fatal: create $c: zero <new-oid>" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
@@ -795,7 +795,7 @@ test_expect_success 'stdin update ref works with right old value' '
 test_expect_success 'stdin delete ref fails with wrong old value' '
 	echo "delete $a $m~1" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: cannot lock ref '"'"'$a'"'"'" err &&
+	test_grep "fatal: cannot lock ref '"'"'$a'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual
@@ -804,7 +804,7 @@ test_expect_success 'stdin delete ref fails with wrong old value' '
 test_expect_success 'stdin delete ref fails with zero old value' '
 	echo "delete $a " >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: delete $a: zero <old-oid>" err &&
+	test_grep "fatal: delete $a: zero <old-oid>" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual
@@ -965,7 +965,7 @@ test_expect_success 'stdin update refs fails with wrong old value' '
 	update $c  ''
 	EOF
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
+	test_grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual &&
@@ -998,123 +998,123 @@ test_expect_success 'stdin -z works on empty input' '
 test_expect_success 'stdin -z fails on empty line' '
 	echo "" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: whitespace before command: " err
+	test_grep "fatal: whitespace before command: " err
 '
 
 test_expect_success 'stdin -z fails on empty command' '
 	printf $F "" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: empty command in input" err
+	test_grep "fatal: empty command in input" err
 '
 
 test_expect_success 'stdin -z fails on only whitespace' '
 	printf $F " " >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: whitespace before command:  " err
+	test_grep "fatal: whitespace before command:  " err
 '
 
 test_expect_success 'stdin -z fails on leading whitespace' '
 	printf $F " create $a" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: whitespace before command:  create $a" err
+	test_grep "fatal: whitespace before command:  create $a" err
 '
 
 test_expect_success 'stdin -z fails on unknown command' '
 	printf $F "unknown $a" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: unknown command: unknown $a" err
+	test_grep "fatal: unknown command: unknown $a" err
 '
 
 test_expect_success 'stdin -z fails create with no ref' '
 	printf $F "create " >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: create: missing <ref>" err
+	test_grep "fatal: create: missing <ref>" err
 '
 
 test_expect_success 'stdin -z fails create with no new value' '
 	printf $F "create $a" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: create $a: unexpected end of input when reading <new-oid>" err
+	test_grep "fatal: create $a: unexpected end of input when reading <new-oid>" err
 '
 
 test_expect_success 'stdin -z fails create with too many arguments' '
 	printf $F "create $a" "$m" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: unknown command: $m" err
+	test_grep "fatal: unknown command: $m" err
 '
 
 test_expect_success 'stdin -z fails update with no ref' '
 	printf $F "update " >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: update: missing <ref>" err
+	test_grep "fatal: update: missing <ref>" err
 '
 
 test_expect_success 'stdin -z fails update with too few args' '
 	printf $F "update $a" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: update $a: unexpected end of input when reading <old-oid>" err
+	test_grep "fatal: update $a: unexpected end of input when reading <old-oid>" err
 '
 
 test_expect_success 'stdin -z emits warning with empty new value' '
 	git update-ref $a $m &&
 	printf $F "update $a" "" "" >stdin &&
 	git update-ref -z --stdin <stdin 2>err &&
-	grep "warning: update $a: missing <new-oid>, treating as zero" err &&
+	test_grep "warning: update $a: missing <new-oid>, treating as zero" err &&
 	test_must_fail git rev-parse --verify -q $a
 '
 
 test_expect_success 'stdin -z fails update with no new value' '
 	printf $F "update $a" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: update $a: unexpected end of input when reading <new-oid>" err
+	test_grep "fatal: update $a: unexpected end of input when reading <new-oid>" err
 '
 
 test_expect_success 'stdin -z fails update with no old value' '
 	printf $F "update $a" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: update $a: unexpected end of input when reading <old-oid>" err
+	test_grep "fatal: update $a: unexpected end of input when reading <old-oid>" err
 '
 
 test_expect_success 'stdin -z fails update with too many arguments' '
 	printf $F "update $a" "$m" "$m" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: unknown command: $m" err
+	test_grep "fatal: unknown command: $m" err
 '
 
 test_expect_success 'stdin -z fails delete with no ref' '
 	printf $F "delete " >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: delete: missing <ref>" err
+	test_grep "fatal: delete: missing <ref>" err
 '
 
 test_expect_success 'stdin -z fails delete with no old value' '
 	printf $F "delete $a" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: delete $a: unexpected end of input when reading <old-oid>" err
+	test_grep "fatal: delete $a: unexpected end of input when reading <old-oid>" err
 '
 
 test_expect_success 'stdin -z fails delete with too many arguments' '
 	printf $F "delete $a" "$m" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: unknown command: $m" err
+	test_grep "fatal: unknown command: $m" err
 '
 
 test_expect_success 'stdin -z fails verify with too many arguments' '
 	printf $F "verify $a" "$m" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: unknown command: $m" err
+	test_grep "fatal: unknown command: $m" err
 '
 
 test_expect_success 'stdin -z fails verify with no old value' '
 	printf $F "verify $a" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: verify $a: unexpected end of input when reading <old-oid>" err
+	test_grep "fatal: verify $a: unexpected end of input when reading <old-oid>" err
 '
 
 test_expect_success 'stdin -z fails option with unknown name' '
 	printf $F "option unknown" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: option unknown: unknown" err
+	test_grep "fatal: option unknown: unknown" err
 '
 
 test_expect_success 'stdin -z fails with duplicate refs' '
@@ -1160,14 +1160,14 @@ test_expect_success 'stdin -z create ref works with path with space to blob' '
 test_expect_success 'stdin -z update ref fails with wrong old value' '
 	printf $F "update $c" "$m" "$m~1" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
+	test_grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
 test_expect_success 'stdin -z update ref fails with bad old value' '
 	printf $F "update $c" "$m" "does-not-exist" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: update $c: invalid <old-oid>: does-not-exist" err &&
+	test_grep "fatal: update $c: invalid <old-oid>: does-not-exist" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
@@ -1176,7 +1176,7 @@ test_expect_success 'stdin -z create ref fails when ref exists' '
 	git rev-parse "$c" >expect &&
 	printf $F "create $c" "$m~1" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
+	test_grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
 	git rev-parse "$c" >actual &&
 	test_cmp expect actual
 '
@@ -1185,28 +1185,28 @@ test_expect_success 'stdin -z create ref fails with bad new value' '
 	git update-ref -d "$c" &&
 	printf $F "create $c" "does-not-exist" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: create $c: invalid <new-oid>: does-not-exist" err &&
+	test_grep "fatal: create $c: invalid <new-oid>: does-not-exist" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
 test_expect_success 'stdin -z create ref fails with empty new value' '
 	printf $F "create $c" "" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: create $c: missing <new-oid>" err &&
+	test_grep "fatal: create $c: missing <new-oid>" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
 test_expect_success 'stdin -z create ref fails with non commit object' '
 	printf $F "create $c" "$(test_oid 001)" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: trying to write ref ${SQ}$c${SQ} with nonexistent object" err &&
+	test_grep "fatal: trying to write ref ${SQ}$c${SQ} with nonexistent object" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
 test_expect_success 'stdin -z update ref fails with non commit object' '
 	printf $F "update $b" "$(test_oid 001)" "" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: trying to write ref ${SQ}$b${SQ} with nonexistent object" err &&
+	test_grep "fatal: trying to write ref ${SQ}$b${SQ} with nonexistent object" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 
@@ -1221,7 +1221,7 @@ test_expect_success 'stdin -z update ref works with right old value' '
 test_expect_success 'stdin -z delete ref fails with wrong old value' '
 	printf $F "delete $a" "$m~1" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: cannot lock ref '"'"'$a'"'"'" err &&
+	test_grep "fatal: cannot lock ref '"'"'$a'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual
@@ -1230,7 +1230,7 @@ test_expect_success 'stdin -z delete ref fails with wrong old value' '
 test_expect_success 'stdin -z delete ref fails with zero old value' '
 	printf $F "delete $a" "$Z" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: delete $a: zero <old-oid>" err &&
+	test_grep "fatal: delete $a: zero <old-oid>" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual
@@ -1336,7 +1336,7 @@ test_expect_success 'stdin -z update refs fails with wrong old value' '
 	git update-ref $c $m &&
 	printf $F "update $a" "$m" "$m" "update $b" "$m" "$m" "update $c" "$m" "$Z" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
+	test_grep "fatal: cannot lock ref '"'"'$c'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual &&
@@ -1415,13 +1415,13 @@ test_expect_success 'handle per-worktree refs in refs/bisect' '
 		cd worktree &&
 		git commit --allow-empty -m "test commit"  &&
 		git for-each-ref >for-each-ref.out &&
-		! grep refs/bisect for-each-ref.out &&
+		test_grep ! refs/bisect for-each-ref.out &&
 		git update-ref refs/bisect/something HEAD &&
 		git rev-parse refs/bisect/something >../worktree-head &&
 		git for-each-ref | grep refs/bisect/something
 	) &&
 	git show-ref >actual &&
-	! grep 'refs/bisect' actual &&
+	test_grep ! 'refs/bisect' actual &&
 	test_must_fail git rev-parse refs/bisect/something &&
 	git update-ref refs/bisect/something HEAD &&
 	git rev-parse refs/bisect/something >main-head &&
@@ -1477,7 +1477,7 @@ test_expect_success 'transaction exits on multiple aborts' '
 	test_must_fail git update-ref --stdin <stdin >actual 2>err &&
 	printf "%s: ok\n" abort >expect &&
 	test_cmp expect actual &&
-	grep "fatal: transaction is closed" err
+	test_grep "fatal: transaction is closed" err
 '
 
 test_expect_success 'transaction exits on start after prepare' '
@@ -1488,7 +1488,7 @@ test_expect_success 'transaction exits on start after prepare' '
 	test_must_fail git update-ref --stdin <stdin 2>err >actual &&
 	printf "%s: ok\n" prepare >expect &&
 	test_cmp expect actual &&
-	grep "fatal: prepared transactions can only be closed" err
+	test_grep "fatal: prepared transactions can only be closed" err
 '
 
 test_expect_success 'transaction handles empty abort with missing prepare' '
@@ -1648,7 +1648,7 @@ test_expect_success PIPE 'transaction flushes status updates' '
 
 	# This must now fail given that we have locked the ref.
 	test_must_fail git update-ref refs/heads/flush $B 2>stderr &&
-	grep "fatal: update_ref failed for ref ${SQ}refs/heads/flush${SQ}: cannot lock ref" stderr &&
+	test_grep "fatal: update_ref failed for ref ${SQ}refs/heads/flush${SQ}: cannot lock ref" stderr &&
 
 	echo commit >&9 &&
 	echo "commit: ok" >expected &&
@@ -1674,7 +1674,7 @@ do
 		git symbolic-ref refs/heads/symref $a &&
 		format_command $type "symref-verify refs/heads/symref" "$a" >stdin &&
 		test_must_fail git update-ref --stdin $type <stdin 2>err &&
-		grep "fatal: symref-verify: cannot operate with deref mode" err
+		test_grep "fatal: symref-verify: cannot operate with deref mode" err
 	'
 
 	test_expect_success "stdin $type symref-verify fails with too many arguments" '
@@ -1682,9 +1682,9 @@ do
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err  &&
 		if test "$type" = "-z"
 		then
-			grep "fatal: unknown command: $a" err
+			test_grep "fatal: unknown command: $a" err
 		else
-			grep "fatal: symref-verify refs/heads/symref: extra input:  $a" err
+			test_grep "fatal: symref-verify refs/heads/symref: extra input:  $a" err
 		fi
 	'
 
@@ -1717,7 +1717,7 @@ do
 		test-tool ref-store main for-each-reflog-ent refs/heads/symref >before &&
 		format_command $type "symref-verify refs/heads/missing" "refs/heads/unknown" >stdin &&
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
-		grep "fatal: cannot lock ref ${SQ}refs/heads/missing${SQ}: unable to resolve reference ${SQ}refs/heads/missing${SQ}" err &&
+		test_grep "fatal: cannot lock ref ${SQ}refs/heads/missing${SQ}: unable to resolve reference ${SQ}refs/heads/missing${SQ}" err &&
 		test_must_fail git rev-parse --verify -q refs/heads/missing &&
 		test-tool ref-store main for-each-reflog-ent refs/heads/symref >after &&
 		test_cmp before after
@@ -1743,13 +1743,13 @@ do
 		git symbolic-ref refs/heads/symref $a &&
 		format_command $type "symref-delete refs/heads/symref" "$a" >stdin &&
 		test_must_fail git update-ref --stdin $type <stdin 2>err &&
-		grep "fatal: symref-delete: cannot operate with deref mode" err
+		test_grep "fatal: symref-delete: cannot operate with deref mode" err
 	'
 
 	test_expect_success "stdin $type symref-delete fails with no ref" '
 		format_command $type "symref-delete " >stdin &&
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
-		grep "fatal: symref-delete: missing <ref>" err
+		test_grep "fatal: symref-delete: missing <ref>" err
 	'
 
 	test_expect_success "stdin $type symref-delete fails deleting regular ref" '
@@ -1757,7 +1757,7 @@ do
 		git update-ref refs/heads/regularref $a &&
 		format_command $type "symref-delete refs/heads/regularref" "$a" >stdin &&
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
-		grep "fatal: cannot lock ref ${SQ}refs/heads/regularref${SQ}: expected symref with target ${SQ}$a${SQ}: but is a regular ref" err
+		test_grep "fatal: cannot lock ref ${SQ}refs/heads/regularref${SQ}: expected symref with target ${SQ}$a${SQ}: but is a regular ref" err
 	'
 
 	test_expect_success "stdin $type symref-delete fails with too many arguments" '
@@ -1765,16 +1765,16 @@ do
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
 		if test "$type" = "-z"
 		then
-			grep "fatal: unknown command: $a" err
+			test_grep "fatal: unknown command: $a" err
 		else
-			grep "fatal: symref-delete refs/heads/symref: extra input:  $a" err
+			test_grep "fatal: symref-delete refs/heads/symref: extra input:  $a" err
 		fi
 	'
 
 	test_expect_success "stdin $type symref-delete fails with wrong old value" '
 		format_command $type "symref-delete refs/heads/symref" "$m" >stdin &&
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
-		grep "fatal: verifying symref target: ${SQ}refs/heads/symref${SQ}: is at $a but expected refs/heads/main" err &&
+		test_grep "fatal: verifying symref target: ${SQ}refs/heads/symref${SQ}: is at $a but expected refs/heads/main" err &&
 		git symbolic-ref refs/heads/symref >expect &&
 		echo $a >actual &&
 		test_cmp expect actual
@@ -1812,9 +1812,9 @@ do
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
 		if test "$type" = "-z"
 		then
-			grep "fatal: unknown command: $a" err
+			test_grep "fatal: unknown command: $a" err
 		else
-			grep "fatal: symref-create refs/heads/symref: extra input:  $a" err
+			test_grep "fatal: symref-create refs/heads/symref: extra input:  $a" err
 		fi
 	'
 
@@ -1877,16 +1877,16 @@ do
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
 		if test "$type" = "-z"
 		then
-			grep "fatal: unknown command: $a" err
+			test_grep "fatal: unknown command: $a" err
 		else
-			grep "fatal: symref-update refs/heads/symref: extra input:  $a" err
+			test_grep "fatal: symref-update refs/heads/symref: extra input:  $a" err
 		fi
 	'
 
 	test_expect_success "stdin $type symref-update fails with wrong old value argument" '
 		format_command $type "symref-update refs/heads/symref" "$a" "foo" "$a" "$a" >stdin &&
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
-		grep "fatal: symref-update refs/heads/symref: invalid arg ${SQ}foo${SQ} for old value" err
+		test_grep "fatal: symref-update refs/heads/symref: invalid arg ${SQ}foo${SQ} for old value" err
 	'
 
 	test_expect_success "stdin $type symref-update creates with zero old value" '
@@ -1922,7 +1922,7 @@ do
 		git symbolic-ref refs/heads/symref $a &&
 		format_command $type "symref-update refs/heads/symref" "$m" "ref" "$b" >stdin &&
 		test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
-		grep "fatal: verifying symref target: ${SQ}refs/heads/symref${SQ}: is at $a but expected $b" err &&
+		test_grep "fatal: verifying symref target: ${SQ}refs/heads/symref${SQ}: is at $a but expected $b" err &&
 		test_must_fail git rev-parse --verify -q $c
 	'
 
@@ -1997,7 +1997,7 @@ do
 		git symbolic-ref --no-recurse refs/heads/symref >actual &&
 		test_cmp expect actual &&
 		test-tool ref-store main for-each-reflog-ent refs/heads/symref >actual &&
-		grep "$Z $(git rev-parse $a)" actual
+		test_grep "$Z $(git rev-parse $a)" actual
 	'
 
 	test_expect_success "stdin $type symref-update regular ref to symref with correct old-oid" '
@@ -2009,7 +2009,7 @@ do
 		git symbolic-ref --no-recurse refs/heads/regularref >actual &&
 		test_cmp expect actual &&
 		test-tool ref-store main for-each-reflog-ent refs/heads/regularref >actual &&
-		grep "$(git rev-parse $a) $(git rev-parse $a)" actual
+		test_grep "$(git rev-parse $a) $(git rev-parse $a)" actual
 	'
 
 	test_expect_success "stdin $type symref-update regular ref to symref fails with wrong old-oid" '
@@ -2017,7 +2017,7 @@ do
 		git update-ref --no-deref refs/heads/regularref $a &&
 		format_command $type "symref-update refs/heads/regularref" "$a" "oid" "$(git rev-parse refs/heads/target2)" >stdin &&
 		test_must_fail git update-ref --stdin $type <stdin 2>err &&
-		grep "fatal: cannot lock ref ${SQ}refs/heads/regularref${SQ}: is at $(git rev-parse $a) but expected $(git rev-parse refs/heads/target2)" err &&
+		test_grep "fatal: cannot lock ref ${SQ}refs/heads/regularref${SQ}: is at $(git rev-parse $a) but expected $(git rev-parse refs/heads/target2)" err &&
 		echo $(git rev-parse $a) >expect &&
 		git rev-parse refs/heads/regularref >actual &&
 		test_cmp expect actual
@@ -2028,7 +2028,7 @@ do
 		git update-ref --no-deref refs/heads/regularref $a &&
 		format_command $type "symref-update refs/heads/regularref" "$a" "oid" "not-a-ref-oid" >stdin &&
 		test_must_fail git update-ref --stdin $type <stdin 2>err &&
-		grep "fatal: symref-update refs/heads/regularref: invalid oid: not-a-ref-oid" err &&
+		test_grep "fatal: symref-update refs/heads/regularref: invalid oid: not-a-ref-oid" err &&
 		echo $(git rev-parse $a) >expect &&
 		git rev-parse refs/heads/regularref >actual &&
 		test_cmp expect actual
@@ -2039,7 +2039,7 @@ do
 		git symbolic-ref refs/heads/symref refs/heads/target2 &&
 		format_command $type "symref-update refs/heads/symref" "$a" "oid" "$Z" >stdin &&
 		test_must_fail git update-ref --stdin $type <stdin 2>err &&
-		grep "fatal: cannot lock ref ${SQ}refs/heads/symref${SQ}: reference already exists" err &&
+		test_grep "fatal: cannot lock ref ${SQ}refs/heads/symref${SQ}: reference already exists" err &&
 		echo refs/heads/target2 >expect &&
 		git symbolic-ref refs/heads/symref >actual &&
 		test_cmp expect actual
@@ -2059,7 +2059,7 @@ do
 		git symbolic-ref --no-recurse refs/heads/symref >actual &&
 		test_cmp expect actual &&
 		test-tool ref-store main for-each-reflog-ent refs/heads/symref >actual &&
-		grep "$(git rev-parse $a) $(git rev-parse $a)" actual
+		test_grep "$(git rev-parse $a) $(git rev-parse $a)" actual
 	'
 
 	test_expect_success "stdin $type symref-update regular ref to symref" '
@@ -2071,7 +2071,7 @@ do
 		git symbolic-ref --no-recurse refs/heads/regularref >actual &&
 		test_cmp expect actual &&
 		test-tool ref-store main for-each-reflog-ent refs/heads/regularref >actual &&
-		grep "$(git rev-parse $a) $(git rev-parse $a)" actual
+		test_grep "$(git rev-parse $a) $(git rev-parse $a)" actual
 	'
 
 	test_expect_success "stdin $type batch-updates" '
diff --git a/t/t1403-show-ref.sh b/t/t1403-show-ref.sh
index 36c903ca19..7ce5af4ab8 100755
--- a/t/t1403-show-ref.sh
+++ b/t/t1403-show-ref.sh
@@ -213,19 +213,19 @@ test_expect_success 'show-ref --verify with dangling ref' '
 
 test_expect_success 'show-ref sub-modes are mutually exclusive' '
 	test_must_fail git show-ref --verify --exclude-existing 2>err &&
-	grep "verify" err &&
-	grep "exclude-existing" err &&
-	grep "cannot be used together" err &&
+	test_grep "verify" err &&
+	test_grep "exclude-existing" err &&
+	test_grep "cannot be used together" err &&
 
 	test_must_fail git show-ref --verify --exists 2>err &&
-	grep "verify" err &&
-	grep "exists" err &&
-	grep "cannot be used together" err &&
+	test_grep "verify" err &&
+	test_grep "exists" err &&
+	test_grep "cannot be used together" err &&
 
 	test_must_fail git show-ref --exclude-existing --exists 2>err &&
-	grep "exclude-existing" err &&
-	grep "exists" err &&
-	grep "cannot be used together" err
+	test_grep "exclude-existing" err &&
+	test_grep "exists" err &&
+	test_grep "cannot be used together" err
 '
 
 test_done
diff --git a/t/t1410-reflog.sh b/t/t1410-reflog.sh
index ce71f9a30a..81de1d40eb 100755
--- a/t/t1410-reflog.sh
+++ b/t/t1410-reflog.sh
@@ -108,12 +108,12 @@ test_expect_success setup '
 
 test_expect_success 'correct usage on sub-command -h' '
 	test_expect_code 129 git reflog expire -h >err &&
-	grep "git reflog expire" err
+	test_grep "git reflog expire" err
 '
 
 test_expect_success 'correct usage on "git reflog show -h"' '
 	test_expect_code 129 git reflog show -h >err &&
-	grep -F "git reflog [show]" err
+	test_grep -F "git reflog [show]" err
 '
 
 test_expect_success 'pass through -- to sub-command' '
diff --git a/t/t1415-worktree-refs.sh b/t/t1415-worktree-refs.sh
index 51d79bae83..6b2ad04aef 100755
--- a/t/t1415-worktree-refs.sh
+++ b/t/t1415-worktree-refs.sh
@@ -32,7 +32,7 @@ test_expect_success 'ambiguous main-worktree/HEAD' '
 	test_when_finished git update-ref -d refs/heads/main-worktree/HEAD &&
 	git update-ref refs/heads/main-worktree/HEAD $(git rev-parse HEAD) &&
 	git rev-parse main-worktree/HEAD 2>warn &&
-	grep "main-worktree/HEAD.*ambiguous" warn
+	test_grep "main-worktree/HEAD.*ambiguous" warn
 '
 
 test_expect_success 'resolve worktrees/xx/HEAD' '
@@ -45,7 +45,7 @@ test_expect_success 'ambiguous worktrees/xx/HEAD' '
 	git update-ref refs/heads/worktrees/wt1/HEAD $(git rev-parse HEAD) &&
 	test_when_finished git update-ref -d refs/heads/worktrees/wt1/HEAD &&
 	git rev-parse worktrees/wt1/HEAD 2>warn &&
-	grep "worktrees/wt1/HEAD.*ambiguous" warn
+	test_grep "worktrees/wt1/HEAD.*ambiguous" warn
 '
 
 test_expect_success 'reflog of main-worktree/HEAD' '
diff --git a/t/t1430-bad-ref-name.sh b/t/t1430-bad-ref-name.sh
index 3ab65f72cd..1ed4c7d2c2 100755
--- a/t/t1430-bad-ref-name.sh
+++ b/t/t1430-bad-ref-name.sh
@@ -47,7 +47,7 @@ test_expect_success 'git branch shows badly named ref as warning' '
 	test_when_finished "test-tool ref-store main delete-refs REF_NO_DEREF msg refs/heads/broken...ref" &&
 	git branch >output 2>error &&
 	test_grep -e "ignoring ref with broken name refs/heads/broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'branch -d can delete badly named ref' '
@@ -55,8 +55,8 @@ test_expect_success 'branch -d can delete badly named ref' '
 	test_when_finished "test-tool ref-store main delete-refs REF_NO_DEREF msg refs/heads/broken...ref" &&
 	git branch -d broken...ref &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'branch -D can delete badly named ref' '
@@ -64,8 +64,8 @@ test_expect_success 'branch -D can delete badly named ref' '
 	test_when_finished "test-tool ref-store main delete-refs REF_NO_DEREF msg refs/heads/broken...ref" &&
 	git branch -D broken...ref &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'branch -D cannot delete non-ref in .git dir' '
@@ -93,8 +93,8 @@ test_expect_success 'git branch cannot create a badly named ref' '
 	test_when_finished "test-tool ref-store main delete-refs REF_NO_DEREF msg refs/heads/broken...ref" &&
 	test_must_fail git branch broken...ref &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'branch -m cannot rename to a bad ref name' '
@@ -104,8 +104,8 @@ test_expect_success 'branch -m cannot rename to a bad ref name' '
 	test_must_fail git branch -m goodref broken...ref &&
 	test_cmp_rev main goodref &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_failure 'branch -m can rename from a bad ref name' '
@@ -115,16 +115,16 @@ test_expect_failure 'branch -m can rename from a bad ref name' '
 	git branch -m broken...ref renamed &&
 	test_cmp_rev main renamed &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'push cannot create a badly named ref' '
 	test_when_finished "test-tool ref-store main delete-refs REF_NO_DEREF msg refs/heads/broken...ref" &&
 	test_must_fail git push "file://$(pwd)" HEAD:refs/heads/broken...ref &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_failure 'push --mirror can delete badly named ref' '
@@ -144,8 +144,8 @@ test_expect_failure 'push --mirror can delete badly named ref' '
 	) &&
 	git -C src push --mirror "file://$top/dest" &&
 	git -C dest branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'rev-parse skips symref pointing to broken name' '
@@ -168,9 +168,9 @@ test_expect_success 'for-each-ref emits warnings for broken names' '
 	test-tool ref-store main create-symref refs/heads/broken...symref refs/heads/main &&
 	test_when_finished "test-tool ref-store main delete-refs REF_NO_DEREF msg refs/heads/broken...symref" &&
 	git for-each-ref >output 2>error &&
-	! grep -e "broken\.\.\.ref" output &&
-	! grep -e "badname" output &&
-	! grep -e "broken\.\.\.symref" output &&
+	test_grep ! -e "broken\.\.\.ref" output &&
+	test_grep ! -e "badname" output &&
+	test_grep ! -e "broken\.\.\.symref" output &&
 	test_grep "ignoring ref with broken name refs/heads/broken\.\.\.ref" error &&
 	test_grep ! "ignoring broken ref refs/heads/badname" error &&
 	test_grep "ignoring ref with broken name refs/heads/broken\.\.\.symref" error
@@ -183,8 +183,8 @@ test_expect_success 'update-ref -d can delete broken name' '
 	test_must_be_empty output &&
 	test_must_be_empty error &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'branch -d can delete broken name' '
@@ -194,8 +194,8 @@ test_expect_success 'branch -d can delete broken name' '
 	test_grep "Deleted branch broken...ref (was broken)" output &&
 	test_must_be_empty error &&
 	git branch >output 2>error &&
-	! grep -e "broken\.\.\.ref" error &&
-	! grep -e "broken\.\.\.ref" output
+	test_grep ! -e "broken\.\.\.ref" error &&
+	test_grep ! -e "broken\.\.\.ref" output
 '
 
 test_expect_success 'update-ref --no-deref -d can delete symref to broken name' '
@@ -313,37 +313,37 @@ test_expect_success 'update-ref -d cannot delete absolute path' '
 test_expect_success 'update-ref --stdin fails create with bad ref name' '
 	echo "create ~a refs/heads/main" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: invalid ref format: ~a" err
+	test_grep "fatal: invalid ref format: ~a" err
 '
 
 test_expect_success 'update-ref --stdin fails update with bad ref name' '
 	echo "update ~a refs/heads/main" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: invalid ref format: ~a" err
+	test_grep "fatal: invalid ref format: ~a" err
 '
 
 test_expect_success 'update-ref --stdin fails delete with bad ref name' '
 	echo "delete ~a refs/heads/main" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: invalid ref format: ~a" err
+	test_grep "fatal: invalid ref format: ~a" err
 '
 
 test_expect_success 'update-ref --stdin -z fails create with bad ref name' '
 	printf "%s\0" "create ~a " refs/heads/main >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: invalid ref format: ~a " err
+	test_grep "fatal: invalid ref format: ~a " err
 '
 
 test_expect_success 'update-ref --stdin -z fails update with bad ref name' '
 	printf "%s\0" "update ~a" refs/heads/main "" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: invalid ref format: ~a" err
+	test_grep "fatal: invalid ref format: ~a" err
 '
 
 test_expect_success 'update-ref --stdin -z fails delete with bad ref name' '
 	printf "%s\0" "delete ~a" refs/heads/main >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: invalid ref format: ~a" err
+	test_grep "fatal: invalid ref format: ~a" err
 '
 
 test_expect_success 'branch rejects HEAD as a branch name' '
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh
index 54e81c2636..47d460a699 100755
--- a/t/t1450-fsck.sh
+++ b/t/t1450-fsck.sh
@@ -68,7 +68,7 @@ test_expect_success 'object with hash mismatch' '
 		git update-ref refs/heads/bogus $cmt &&
 
 		test_must_fail git fsck 2>out &&
-		grep "$oldoid: hash-path mismatch, found at: .*$new" out
+		test_grep "$oldoid: hash-path mismatch, found at: .*$new" out
 	)
 '
 
@@ -172,7 +172,7 @@ test_expect_success 'commit with multiple signatures is okay' '
 	test_when_finished "git update-ref -d refs/heads/bogus" &&
 	git fsck 2>out &&
 	cat out &&
-	! grep "commit $new" out
+	test_grep ! "commit $new" out
 '
 
 test_expect_success 'email without @ is okay' '
@@ -183,7 +183,7 @@ test_expect_success 'email without @ is okay' '
 	git update-ref refs/heads/bogus "$new" &&
 	test_when_finished "git update-ref -d refs/heads/bogus" &&
 	git fsck 2>out &&
-	! grep "commit $new" out
+	test_grep ! "commit $new" out
 '
 
 test_expect_success 'email with embedded > is not okay' '
@@ -626,7 +626,7 @@ test_expect_success 'fsck notices excessively large tree entry name' '
 		cd large-name &&
 		test_commit a-long-name &&
 		git -c fsck.largePathname=warn:10 fsck 2>out &&
-		grep "warning.*large pathname" out
+		test_grep "warning.*large pathname" out
 	)
 '
 
@@ -849,7 +849,7 @@ test_expect_success 'fsck errors in packed objects' '
 	test_must_fail git fsck 2>out &&
 	test_grep "error in commit $one.* - bad name" out &&
 	test_grep "error in commit $two.* - bad name" out &&
-	! grep corrupt out
+	test_grep ! corrupt out
 '
 
 test_expect_success 'fsck handles multiple packfiles with big blobs' '
@@ -1027,7 +1027,7 @@ test_expect_success 'bogus head does not fallback to all heads' '
 	test_when_finished "git rm --cached foo" &&
 	remove_object $blob &&
 	test_must_fail git fsck $ZERO_OID >out 2>&1 &&
-	! grep $blob out
+	test_grep ! $blob out
 '
 
 # Corrupt the checksum on the index.
diff --git a/t/t1451-fsck-buffer.sh b/t/t1451-fsck-buffer.sh
index 3a3d33f405..14151eabbd 100755
--- a/t/t1451-fsck-buffer.sh
+++ b/t/t1451-fsck-buffer.sh
@@ -46,7 +46,7 @@ check () {
 			echo "$content"
 		} >input &&
 		test_must_fail git hash-object -t "$type" input 2>err &&
-		grep "$fsck" err
+		test_grep "$fsck" err
 	'
 }
 
@@ -125,7 +125,7 @@ ident_checks tag tagger
 test_expect_success 'truncated tree (short hash)' '
 	printf "100644 foo\0\1\1\1\1" >input &&
 	test_must_fail git hash-object -t tree input 2>err &&
-	grep badTree err
+	test_grep badTree err
 '
 
 test_expect_success 'truncated tree (missing nul)' '
@@ -135,7 +135,7 @@ test_expect_success 'truncated tree (missing nul)' '
 	# parser does not walk past the end of the buffer).
 	printf "100644 a long filename, or a hash with missing nul?" >input &&
 	test_must_fail git hash-object -t tree input 2>err &&
-	grep badTree err
+	test_grep badTree err
 '
 
 test_done
diff --git a/t/t1460-refs-migrate.sh b/t/t1460-refs-migrate.sh
index 5246468024..8f42697143 100755
--- a/t/t1460-refs-migrate.sh
+++ b/t/t1460-refs-migrate.sh
@@ -212,7 +212,7 @@ do
 			test_commit -C repo initial &&
 			git -C repo refs migrate --dry-run \
 				--ref-format=$to_format >output &&
-			grep "Finished dry-run migration of refs" output &&
+			test_grep "Finished dry-run migration of refs" output &&
 			test_path_is_dir repo/.git/ref_migration.* &&
 			echo $from_format >expect &&
 			git -C repo rev-parse --show-ref-format >actual &&
diff --git a/t/t1500-rev-parse.sh b/t/t1500-rev-parse.sh
index 38067d95f7..4174ca40c3 100755
--- a/t/t1500-rev-parse.sh
+++ b/t/t1500-rev-parse.sh
@@ -204,7 +204,7 @@ test_expect_success 'rev-parse --show-object-format in repo' '
 	git rev-parse --show-object-format=output >actual &&
 	test_cmp expect actual &&
 	test_must_fail git rev-parse --show-object-format=squeamish-ossifrage 2>err &&
-	grep "unknown mode for --show-object-format: squeamish-ossifrage" err
+	test_grep "unknown mode for --show-object-format: squeamish-ossifrage" err
 '
 
 
@@ -228,7 +228,7 @@ test_expect_success RUST 'rev-parse --show-object-format in repo with compat mod
 		git rev-parse --show-object-format=compat >actual &&
 		test_cmp expect actual &&
 		test_must_fail git rev-parse --show-object-format=squeamish-ossifrage 2>err &&
-		grep "unknown mode for --show-object-format: squeamish-ossifrage" err
+		test_grep "unknown mode for --show-object-format: squeamish-ossifrage" err
 	) &&
 	mkdir repo2 &&
 	(
@@ -254,7 +254,7 @@ test_expect_success 'rev-parse --show-ref-format with invalid storage' '
 		cd repo &&
 		git config extensions.refstorage broken &&
 		test_must_fail git rev-parse --show-ref-format 2>err &&
-		grep "error: invalid value for ${SQ}extensions.refstorage${SQ}: ${SQ}broken${SQ}" err
+		test_grep "error: invalid value for ${SQ}extensions.refstorage${SQ}: ${SQ}broken${SQ}" err
 	)
 '
 
diff --git a/t/t1502-rev-parse-parseopt.sh b/t/t1502-rev-parse-parseopt.sh
index 3962f1d288..2cab204376 100755
--- a/t/t1502-rev-parse-parseopt.sh
+++ b/t/t1502-rev-parse-parseopt.sh
@@ -331,7 +331,7 @@ test_expect_success 'ambiguous: --no matches both --noble and --no-noble' '
 	EOF
 	test_expect_code 129 env GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS=false \
 	git rev-parse --parseopt -- <spec 2>err --no &&
-	grep "error: ambiguous option: no (could be --noble or --no-noble)" err
+	test_grep "error: ambiguous option: no (could be --noble or --no-noble)" err
 '
 
 test_done
diff --git a/t/t1503-rev-parse-verify.sh b/t/t1503-rev-parse-verify.sh
index 75a708f9ba..87638a4a2c 100755
--- a/t/t1503-rev-parse-verify.sh
+++ b/t/t1503-rev-parse-verify.sh
@@ -62,15 +62,15 @@ test_expect_success 'works with one good rev' '
 
 test_expect_success 'fails with any bad rev or many good revs' '
 	test_must_fail git rev-parse --verify 2>error &&
-	grep "single revision" error &&
+	test_grep "single revision" error &&
 	test_must_fail git rev-parse --verify foo 2>error &&
-	grep "single revision" error &&
+	test_grep "single revision" error &&
 	test_must_fail git rev-parse --verify HEAD bar 2>error &&
-	grep "single revision" error &&
+	test_grep "single revision" error &&
 	test_must_fail git rev-parse --verify baz HEAD 2>error &&
-	grep "single revision" error &&
+	test_grep "single revision" error &&
 	test_must_fail git rev-parse --verify $HASH2 HEAD 2>error &&
-	grep "single revision" error
+	test_grep "single revision" error
 '
 
 test_expect_success 'fails silently when using -q' '
diff --git a/t/t1510-repo-setup.sh b/t/t1510-repo-setup.sh
index bbfe05b8e4..d330b8df47 100755
--- a/t/t1510-repo-setup.sh
+++ b/t/t1510-repo-setup.sh
@@ -604,7 +604,7 @@ test_expect_success '#20b/c: core.worktree and core.bare conflict' '
 		cd 20b/.git &&
 		test_must_fail git status >/dev/null
 	) 2>message &&
-	grep "core.bare and core.worktree" message
+	test_grep "core.bare and core.worktree" message
 '
 
 test_expect_success '#20d: core.worktree and core.bare OK when working tree not needed' '
@@ -721,8 +721,8 @@ test_expect_success '#22.2: core.worktree and core.bare conflict' '
 		export GIT_DIR &&
 		test_must_fail git status 2>result
 	) &&
-	grep "core.bare and core.worktree" 22/.git/result &&
-	grep "core.bare and core.worktree" 22/result
+	test_grep "core.bare and core.worktree" 22/.git/result &&
+	test_grep "core.bare and core.worktree" 22/result
 '
 
 # Case #23: GIT_DIR + GIT_WORK_TREE(+core.worktree) suppresses bareness.
@@ -767,7 +767,7 @@ test_expect_success '#28: core.worktree and core.bare conflict (gitfile case)' '
 		cd 28 &&
 		test_must_fail git status
 	) 2>message &&
-	grep "core.bare and core.worktree" message
+	test_grep "core.bare and core.worktree" message
 '
 
 # Case #29: GIT_WORK_TREE(+core.worktree) overrides core.bare (gitfile case).
@@ -791,7 +791,7 @@ test_expect_success '#30: core.worktree and core.bare conflict (gitfile version)
 		cd 30 &&
 		test_must_fail env GIT_DIR=.git git status 2>result
 	) &&
-	grep "core.bare and core.worktree" 30/result
+	test_grep "core.bare and core.worktree" 30/result
 '
 
 # Case #31: GIT_DIR + GIT_WORK_TREE(+core.worktree) suppresses
diff --git a/t/t1512-rev-parse-disambiguation.sh b/t/t1512-rev-parse-disambiguation.sh
index 1a380a4184..0e6b42ec78 100755
--- a/t/t1512-rev-parse-disambiguation.sh
+++ b/t/t1512-rev-parse-disambiguation.sh
@@ -378,7 +378,7 @@ test_expect_success 'ambiguous 40-hex ref' '
 	VAL=$(git commit-tree $TREE </dev/null) &&
 	git update-ref refs/heads/$REF $VAL &&
 	test $(git rev-parse $REF 2>err) = $REF &&
-	grep "refname.*${REF}.*ambiguous" err
+	test_grep "refname.*${REF}.*ambiguous" err
 '
 
 test_expect_success 'ambiguous short sha1 ref' '
@@ -387,7 +387,7 @@ test_expect_success 'ambiguous short sha1 ref' '
 	VAL=$(git commit-tree $TREE </dev/null) &&
 	git update-ref refs/heads/$REF $VAL &&
 	test $(git rev-parse $REF 2>err) = $VAL &&
-	grep "refname.*${REF}.*ambiguous" err
+	test_grep "refname.*${REF}.*ambiguous" err
 '
 
 test_expect_success 'ambiguity errors are not repeated (raw)' '
diff --git a/t/t1515-rev-parse-outside-repo.sh b/t/t1515-rev-parse-outside-repo.sh
index 75e89c4b6e..2cb3c7cc9c 100755
--- a/t/t1515-rev-parse-outside-repo.sh
+++ b/t/t1515-rev-parse-outside-repo.sh
@@ -32,7 +32,7 @@ test_expect_success 'rev-parse --local-env-vars' '
 	git rev-parse --local-env-vars >actual &&
 	# we do not want to depend on the complete list here,
 	# so just look for something plausible
-	grep ^GIT_DIR actual
+	test_grep ^GIT_DIR actual
 '
 
 test_expect_success 'rev-parse --resolve-git-dir' '
diff --git a/t/t1800-hook.sh b/t/t1800-hook.sh
index 0132e772e4..9aae3ff074 100755
--- a/t/t1800-hook.sh
+++ b/t/t1800-hook.sh
@@ -79,7 +79,7 @@ test_expect_success 'git hook usage' '
 	test_expect_code 129 git hook run --unknown 2>err &&
 	test_expect_code 129 git hook list &&
 	test_expect_code 129 git hook list -h &&
-	grep "unknown option" err
+	test_grep "unknown option" err
 '
 
 test_expect_success 'git hook list: unknown hook name is rejected' '
@@ -361,9 +361,9 @@ test_expect_success 'hook can be configured for multiple events' '
 
 	# 'ghi' should be included in both 'pre-commit' and 'test-hook'
 	git hook list pre-commit >actual &&
-	grep "ghi" actual &&
+	test_grep "ghi" actual &&
 	git hook list --allow-unknown-hook-name test-hook >actual &&
-	grep "ghi" actual
+	test_grep "ghi" actual
 '
 
 test_expect_success 'git hook list shows hooks from the hookdir' '
@@ -569,7 +569,7 @@ test_expect_success 'git hook run a hook with a bad shebang' '
 	# TODO: We should emit the same (or at least a more similar)
 	# error on MINGW (essentially Git for Windows) and all other
 	# platforms.. See the OS-specific code in start_command()
-	grep -E "^(error|fatal): cannot (exec|spawn) .*bad-hooks/test-hook" err
+	test_grep -E "^(error|fatal): cannot (exec|spawn) .*bad-hooks/test-hook" err
 '
 
 test_expect_success 'stdin to hooks' '
@@ -826,8 +826,8 @@ test_expect_success 'git hook run -j2 warns for hooks not marked parallel=true'
 	# neither hook has parallel=true
 
 	git hook run --allow-unknown-hook-name -j2 test-hook >out 2>err &&
-	grep "hook .hook-1. is not marked as parallel=true" err &&
-	grep "hook .hook-2. is not marked as parallel=true" err
+	test_grep "hook .hook-1. is not marked as parallel=true" err &&
+	test_grep "hook .hook-2. is not marked as parallel=true" err
 '
 
 test_expect_success 'hook.jobs=1 config runs hooks in series' '
@@ -1068,7 +1068,7 @@ test_expect_success 'hook.jobs=-1 resolves to online_cpus()' '
 	cpus=$(test-tool online-cpus) &&
 	GIT_TRACE2_EVENT="$(pwd)/trace.txt" \
 		git hook run --allow-unknown-hook-name test-hook >out 2>err &&
-	grep "\"region_enter\".*\"hook\".*\"test-hook\".*\"max:$cpus\"" trace.txt
+	test_grep "\"region_enter\".*\"hook\".*\"test-hook\".*\"max:$cpus\"" trace.txt
 '
 
 test_expect_success 'hook.<event>.jobs=-1 resolves to online_cpus()' '
@@ -1081,7 +1081,7 @@ test_expect_success 'hook.<event>.jobs=-1 resolves to online_cpus()' '
 	cpus=$(test-tool online-cpus) &&
 	GIT_TRACE2_EVENT="$(pwd)/trace.txt" \
 		git hook run --allow-unknown-hook-name test-hook >out 2>err &&
-	grep "\"region_enter\".*\"hook\".*\"test-hook\".*\"max:$cpus\"" trace.txt
+	test_grep "\"region_enter\".*\"hook\".*\"test-hook\".*\"max:$cpus\"" trace.txt
 '
 
 test_expect_success 'git hook run -j-1 resolves to online_cpus()' '
@@ -1092,7 +1092,7 @@ test_expect_success 'git hook run -j-1 resolves to online_cpus()' '
 	cpus=$(test-tool online-cpus) &&
 	GIT_TRACE2_EVENT="$(pwd)/trace.txt" \
 		git hook run --allow-unknown-hook-name -j-1 test-hook >out 2>err &&
-	grep "\"region_enter\".*\"hook\".*\"test-hook\".*\"max:$cpus\"" trace.txt
+	test_grep "\"region_enter\".*\"hook\".*\"test-hook\".*\"max:$cpus\"" trace.txt
 '
 
 test_expect_success 'hook.jobs rejects values less than -1' '
diff --git a/t/t2004-checkout-cache-temp.sh b/t/t2004-checkout-cache-temp.sh
index 0afe0ff7ca..db06c321ed 100755
--- a/t/t2004-checkout-cache-temp.sh
+++ b/t/t2004-checkout-cache-temp.sh
@@ -132,8 +132,8 @@ test_expect_success 'overriding --stage=all resets implied --temp' '
 test_expect_success '--stage=all --no-temp is rejected' '
 	rm -f path* .merge_* actual &&
 	test_must_fail git checkout-index --stage=all --no-temp -- path1 2>err &&
-	grep -v "already exists" err &&
-	grep "options .--stage=all. and .--no-temp. cannot be used together" err
+	test_grep -v "already exists" err &&
+	test_grep "options .--stage=all. and .--no-temp. cannot be used together" err
 '
 
 test_expect_success 'checkout some stages/one file to temporary files' '
diff --git a/t/t2019-checkout-ambiguous-ref.sh b/t/t2019-checkout-ambiguous-ref.sh
index 1fcef4be95..0ac35798c2 100755
--- a/t/t2019-checkout-ambiguous-ref.sh
+++ b/t/t2019-checkout-ambiguous-ref.sh
@@ -19,7 +19,7 @@ test_expect_success 'checkout ambiguous ref succeeds' '
 '
 
 test_expect_success 'checkout produces ambiguity warning' '
-	grep "warning.*ambiguous" stderr
+	test_grep "warning.*ambiguous" stderr
 '
 
 test_expect_success 'checkout chooses branch over tag' '
@@ -41,7 +41,7 @@ test_expect_success 'checkout vague ref succeeds' '
 '
 
 test_expect_success VAGUENESS_SUCCESS 'checkout produces ambiguity warning' '
-	grep "warning.*ambiguous" stderr
+	test_grep "warning.*ambiguous" stderr
 '
 
 test_expect_success VAGUENESS_SUCCESS 'checkout chooses branch over tag' '
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index a3b1449ef1..752e7f0e61 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -311,7 +311,7 @@ test_expect_success 'loosely defined local base branch is reported correctly' '
 	git checkout loose >actual.raw 2>&1 &&
 	sed -e "s/loose/BRANCHNAME/g" <actual.raw >actual &&
 	status_uno_is_clean &&
-	grep BRANCHNAME actual &&
+	test_grep BRANCHNAME actual &&
 
 	test_cmp expect actual
 '
@@ -324,7 +324,7 @@ test_expect_success 'reject when arg could be part of dwim branch' '
 	echo bar >dwim-arg &&
 	test_must_fail git checkout dwim-arg &&
 	test_must_fail git rev-parse refs/heads/dwim-arg -- &&
-	grep bar dwim-arg
+	test_grep bar dwim-arg
 '
 
 test_expect_success 'disambiguate dwim branch and checkout path (1)' '
@@ -334,7 +334,7 @@ test_expect_success 'disambiguate dwim branch and checkout path (1)' '
 	echo bar >dwim-arg1 &&
 	git checkout -- dwim-arg1 &&
 	test_must_fail git rev-parse refs/heads/dwim-arg1 -- &&
-	grep foo dwim-arg1
+	test_grep foo dwim-arg1
 '
 
 test_expect_success 'disambiguate dwim branch and checkout path (2)' '
@@ -344,7 +344,7 @@ test_expect_success 'disambiguate dwim branch and checkout path (2)' '
 	echo bar >dwim-arg2 &&
 	git checkout dwim-arg2 -- &&
 	git rev-parse refs/heads/dwim-arg2 -- &&
-	grep bar dwim-arg2
+	test_grep bar dwim-arg2
 '
 
 test_done
diff --git a/t/t2030-unresolve-info.sh b/t/t2030-unresolve-info.sh
index be3fcdde07..9af24b1204 100755
--- a/t/t2030-unresolve-info.sh
+++ b/t/t2030-unresolve-info.sh
@@ -122,7 +122,7 @@ test_expect_success 'add records checkout -m undoes' '
 	check_resolve_undo removed &&
 	echo the index and the work tree is unmerged again &&
 	git diff >actual &&
-	grep "^++<<<<<<<" actual
+	test_grep "^++<<<<<<<" actual
 '
 
 test_expect_success 'unmerge with plumbing' '
@@ -173,7 +173,7 @@ test_expect_success 'rerere and rerere forget' '
 	test -f .git/rr-cache/$rerere_id/postimage &&
 	git checkout -m fi/le &&
 	echo resurrect the conflict &&
-	grep "^=======" fi/le &&
+	test_grep "^=======" fi/le &&
 	echo reresolve the conflict &&
 	git rerere &&
 	test "z$(cat fi/le)" = zdifferent &&
@@ -199,7 +199,7 @@ test_expect_success 'rerere and rerere forget (subdirectory)' '
 	test -f .git/rr-cache/$rerere_id/postimage &&
 	(cd fi && git checkout -m le) &&
 	echo resurrect the conflict &&
-	grep "^=======" fi/le &&
+	test_grep "^=======" fi/le &&
 	echo reresolve the conflict &&
 	(cd fi && git rerere) &&
 	test "z$(cat fi/le)" = zdifferent &&
diff --git a/t/t2060-switch.sh b/t/t2060-switch.sh
index c91c4db936..cec2fe6876 100755
--- a/t/t2060-switch.sh
+++ b/t/t2060-switch.sh
@@ -34,13 +34,13 @@ test_expect_success 'switch and detach' '
 
 test_expect_success 'suggestion to detach' '
 	test_must_fail git switch main^{commit} 2>stderr &&
-	grep "try again with the --detach option" stderr
+	test_grep "try again with the --detach option" stderr
 '
 
 test_expect_success 'suggestion to detach is suppressed with advice.suggestDetachingHead=false' '
 	test_config advice.suggestDetachingHead false &&
 	test_must_fail git switch main^{commit} 2>stderr &&
-	! grep "try again with the --detach option" stderr
+	test_grep ! "try again with the --detach option" stderr
 '
 
 test_expect_success 'switch and detach current branch' '
@@ -76,7 +76,7 @@ test_expect_success 'new orphan branch from empty' '
 	git switch --orphan new-orphan &&
 	test_commit orphan &&
 	git cat-file commit refs/heads/new-orphan >commit &&
-	! grep ^parent commit &&
+	test_grep ! ^parent commit &&
 	git ls-files >tracked-files &&
 	echo orphan.t >expected &&
 	test_cmp expected tracked-files
diff --git a/t/t2070-restore.sh b/t/t2070-restore.sh
index 16d6348b69..2c222fb934 100755
--- a/t/t2070-restore.sh
+++ b/t/t2070-restore.sh
@@ -216,7 +216,7 @@ test_expect_success 'restore with merge options are incompatible with certain op
 		"--staged --worktree --conflict=zdiff3"
 	do
 		test_must_fail git restore $opts . 2>err &&
-		grep "cannot be used" err || return
+		test_grep "cannot be used" err || return
 	done
 '
 
diff --git a/t/t2080-parallel-checkout-basics.sh b/t/t2080-parallel-checkout-basics.sh
index 5ffe1a41e2..88a6ec1826 100755
--- a/t/t2080-parallel-checkout-basics.sh
+++ b/t/t2080-parallel-checkout-basics.sh
@@ -200,13 +200,13 @@ test_expect_success 'parallel checkout respects --[no]-force' '
 		# We expect 0 workers because there is nothing to be done
 		test_checkout_workers 0 git checkout HEAD &&
 		test_path_is_file D &&
-		grep changed D &&
-		grep changed F.t &&
+		test_grep changed D &&
+		test_grep changed F.t &&
 
 		test_checkout_workers 2 git checkout --force HEAD &&
 		test_path_is_dir D &&
-		grep D/F D/F.t &&
-		grep F F.t
+		test_grep D/F D/F.t &&
+		test_grep F F.t
 	)
 '
 
@@ -224,8 +224,8 @@ test_expect_success SYMLINKS 'parallel checkout checks for symlinks in leading d
 
 		test_checkout_workers 2 git checkout --force HEAD &&
 		! test -h D &&
-		grep D/A D/A.t &&
-		grep D/B D/B.t
+		test_grep D/A D/A.t &&
+		test_grep D/B D/B.t
 	)
 '
 
@@ -268,7 +268,7 @@ test_expect_success '"git checkout ." report should not include failed entries'
 		#  - missing-delay.a: the delay filter will drop this path
 		#  - parallel-*.a: the blob will be missing
 		#
-		grep "Updated 3 paths from the index" err &&
+		test_grep "Updated 3 paths from the index" err &&
 		test_stdout_line_count = 3 ls *.b &&
 		! ls *.a
 	)
diff --git a/t/t2081-parallel-checkout-collisions.sh b/t/t2081-parallel-checkout-collisions.sh
index f6fcfc0c1e..db45f5f30f 100755
--- a/t/t2081-parallel-checkout-collisions.sh
+++ b/t/t2081-parallel-checkout-collisions.sh
@@ -78,8 +78,8 @@ test_expect_success CASE_INSENSITIVE_FS 'worker detects dirname collision' '
 
 	# Check that it used the right number of workers and detected the collisions
 	test_workers_in_event_trace 2 trace &&
-	grep "category.:.pcheckout.,.key.:.collision/dirname.,.value.:.A/B.}" trace &&
-	grep "category.:.pcheckout.,.key.:.collision/dirname.,.value.:.A/C.}" trace
+	test_grep "category.:.pcheckout.,.key.:.collision/dirname.,.value.:.A/B.}" trace &&
+	test_grep "category.:.pcheckout.,.key.:.collision/dirname.,.value.:.A/C.}" trace
 '
 
 test_expect_success SYMLINKS,CASE_INSENSITIVE_FS 'do not follow symlinks colliding with leading dir' '
@@ -115,11 +115,11 @@ test_expect_success CASE_INSENSITIVE_FS 'collision report on clone (w/ racy file
 	set_checkout_config 2 0 &&
 	test_checkout_workers 2 git clone . clone-repo 2>stderr &&
 
-	grep FILE_X stderr &&
-	grep FILE_x stderr &&
-	grep file_X stderr &&
-	grep file_x stderr &&
-	grep "the following paths have collided" stderr
+	test_grep FILE_X stderr &&
+	test_grep FILE_x stderr &&
+	test_grep file_X stderr &&
+	test_grep file_x stderr &&
+	test_grep "the following paths have collided" stderr
 '
 
 # This test ensures that the collision report code is correctly looking for
@@ -148,11 +148,11 @@ test_expect_success CASE_INSENSITIVE_FS,!MINGW,!CYGWIN \
 	test_checkout_workers 2 \
 		git -c core.ignoreCase=false clone . clone-repo 2>stderr &&
 
-	grep FILE_X stderr &&
-	grep FILE_x stderr &&
-	grep file_X stderr &&
-	grep file_x stderr &&
-	grep "the following paths have collided" stderr &&
+	test_grep FILE_X stderr &&
+	test_grep FILE_x stderr &&
+	test_grep file_X stderr &&
+	test_grep file_x stderr &&
+	test_grep "the following paths have collided" stderr &&
 
 	# Check that only "file_x" was filtered
 	echo file_x >expected.log &&
diff --git a/t/t2082-parallel-checkout-attributes.sh b/t/t2082-parallel-checkout-attributes.sh
index 79fb11f139..1f43c2a267 100755
--- a/t/t2082-parallel-checkout-attributes.sh
+++ b/t/t2082-parallel-checkout-attributes.sh
@@ -28,8 +28,8 @@ test_expect_success 'parallel-checkout with ident' '
 		rm A B &&
 		test_checkout_workers 2 git reset --hard &&
 		hexsz=$(test_oid hexsz) &&
-		grep -E "\\\$Id: [0-9a-f]{$hexsz} \\\$" A &&
-		grep "\\\$Id\\\$" B
+		test_grep -E "\\\$Id: [0-9a-f]{$hexsz} \\\$" A &&
+		test_grep "\\\$Id\\\$" B
 	)
 '
 
@@ -175,15 +175,15 @@ test_expect_success 'parallel-checkout and delayed checkout' '
 	verify_checkout delayed &&
 
 	# Check that the *.d files got to the delay queue and were filtered
-	grep "smudge W.d .* \[DELAYED\]" delayed.log &&
-	grep "smudge X.d .* \[DELAYED\]" delayed.log &&
+	test_grep "smudge W.d .* \[DELAYED\]" delayed.log &&
+	test_grep "smudge X.d .* \[DELAYED\]" delayed.log &&
 	test_cmp delayed/W.d original &&
 	test_cmp delayed/X.d original &&
 
 	# Check that the parallel-eligible entries went to the right queue and
 	# were not filtered
-	! grep "smudge Y .* \[DELAYED\]" delayed.log &&
-	! grep "smudge Z .* \[DELAYED\]" delayed.log &&
+	test_grep ! "smudge Y .* \[DELAYED\]" delayed.log &&
+	test_grep ! "smudge Z .* \[DELAYED\]" delayed.log &&
 	test_cmp delayed/Y original &&
 	test_cmp delayed/Z original
 '
diff --git a/t/t2103-update-index-ignore-missing.sh b/t/t2103-update-index-ignore-missing.sh
index 6938ecca86..fbfc86b1fa 100755
--- a/t/t2103-update-index-ignore-missing.sh
+++ b/t/t2103-update-index-ignore-missing.sh
@@ -63,9 +63,9 @@ test_expect_success '--unmerged --refresh' '
 	git update-index --unmerged --refresh &&
 	echo 2 >two &&
 	test_must_fail git update-index --unmerged --refresh >actual &&
-	grep two actual &&
-	! grep one actual &&
-	! grep three actual
+	test_grep two actual &&
+	test_grep ! one actual &&
+	test_grep ! three actual
 '
 
 test_expect_success '--ignore-submodules --refresh (1)' '
diff --git a/t/t2200-add-update.sh b/t/t2200-add-update.sh
index 0a96655cfe..bb019d7a7c 100755
--- a/t/t2200-add-update.sh
+++ b/t/t2200-add-update.sh
@@ -241,7 +241,7 @@ test_expect_success 'add -u avoids rename pairing on unmerged paths' '
 test_expect_success '"add -u non-existent" should fail' '
 	test_must_fail git add -u non-existent &&
 	git ls-files >actual &&
-	! grep "non-existent" actual
+	test_grep ! "non-existent" actual
 '
 
 test_expect_success '"commit -a" implies "add -u" if index becomes empty' '
diff --git a/t/t2203-add-intent.sh b/t/t2203-add-intent.sh
index 44c1936e4d..69fef7e646 100755
--- a/t/t2203-add-intent.sh
+++ b/t/t2203-add-intent.sh
@@ -57,7 +57,7 @@ test_expect_success 'intent to add does not clobber existing paths' '
 	git add -N file elif &&
 	empty=$(git hash-object --stdin </dev/null) &&
 	git ls-files -s >actual &&
-	! grep "$empty" actual
+	test_grep ! "$empty" actual
 '
 
 test_expect_success 'i-t-a entry is simply ignored' '
@@ -124,7 +124,7 @@ test_expect_success 'cache-tree does not ignore dir that has i-t-a entries' '
 		git add -N 2/1 &&
 		git commit -m committed &&
 		git ls-tree -r HEAD >actual &&
-		grep 2/2 actual
+		test_grep 2/2 actual
 	)
 '
 
@@ -312,7 +312,7 @@ test_expect_success 'apply --intent-to-add' '
 	echo new >new-ita &&
 	git add -N new-ita &&
 	git diff >expected &&
-	grep "new file" expected &&
+	test_grep "new file" expected &&
 	git reset --hard &&
 	git apply --intent-to-add expected &&
 	git diff >actual &&
diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
index 58b4445cc4..87b926728a 100755
--- a/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@ -122,7 +122,7 @@ test_expect_success 'die the same branch is already checked out' '
 	(
 		cd here &&
 		test_must_fail git checkout newmain 2>actual &&
-		grep "already used by worktree at" actual
+		test_grep "already used by worktree at" actual
 	)
 '
 
@@ -139,7 +139,7 @@ test_expect_success 'refuse to reset a branch in use elsewhere' '
 		git rev-parse --verify refs/heads/newmain >new.branch &&
 		git rev-parse --verify HEAD >new.head &&
 
-		grep "already used by worktree at" error &&
+		test_grep "already used by worktree at" error &&
 		test_cmp old.branch new.branch &&
 		test_cmp old.head new.head &&
 
@@ -328,7 +328,7 @@ test_wt_add_excl () {
 	local opts="$*" &&
 	test_expect_success "'worktree add' with '$opts' has mutually exclusive options" '
 		test_must_fail git worktree add $opts 2>actual &&
-		grep -E "fatal:( options)? .* cannot be used together" actual
+		test_grep -E "fatal:( options)? .* cannot be used together" actual
 	'
 }
 
@@ -436,13 +436,13 @@ test_wt_add_orphan_hint () {
 		(cd repo && test_commit commit) &&
 		git -C repo switch --orphan noref &&
 		test_must_fail git -C repo worktree add $opts foobar/ 2>actual &&
-		! grep "error: unknown switch" actual &&
-		grep "hint: If you meant to create a worktree containing a new unborn branch" actual &&
+		test_grep ! "error: unknown switch" actual &&
+		test_grep "hint: If you meant to create a worktree containing a new unborn branch" actual &&
 		if [ $use_branch -eq 1 ]
 		then
-			grep -E "^hint: +git worktree add --orphan -b [^ ]+ [^ ]+$" actual
+			test_grep -E "^hint: +git worktree add --orphan -b [^ ]+ [^ ]+$" actual
 		else
-			grep -E "^hint: +git worktree add --orphan [^ ]+$" actual
+			test_grep -E "^hint: +git worktree add --orphan [^ ]+$" actual
 		fi
 
 	'
@@ -457,8 +457,8 @@ test_expect_success "'worktree add' doesn't show orphan hint in bad/orphan HEAD
 	git init repo &&
 	(cd repo && test_commit commit) &&
 	test_must_fail git -C repo worktree add --quiet foobar_branch foobar/ 2>actual &&
-	! grep "error: unknown switch" actual &&
-	! grep "hint: If you meant to create a worktree containing a new unborn branch" actual
+	test_grep ! "error: unknown switch" actual &&
+	test_grep ! "hint: If you meant to create a worktree containing a new unborn branch" actual
 '
 
 test_expect_success 'local clone from linked checkout' '
@@ -469,7 +469,7 @@ test_expect_success 'local clone from linked checkout' '
 test_expect_success 'local clone --shared from linked checkout' '
 	git -C bare worktree add --detach ../baretree &&
 	git clone --local --shared baretree bare-clone &&
-	grep /bare/ bare-clone/.git/objects/info/alternates
+	test_grep /bare/ bare-clone/.git/objects/info/alternates
 '
 
 test_expect_success '"add" worktree with --no-checkout' '
@@ -491,7 +491,7 @@ test_expect_success 'put a worktree under rebase' '
 		set_fake_editor &&
 		FAKE_LINES="edit 1" git rebase -i HEAD^ &&
 		git worktree list >actual &&
-		grep "under-rebase.*detached HEAD" actual
+		test_grep "under-rebase.*detached HEAD" actual
 	)
 '
 
@@ -533,7 +533,7 @@ test_expect_success 'checkout a branch under bisect' '
 		git bisect bad &&
 		git bisect good HEAD~2 &&
 		git worktree list >actual &&
-		grep "under-bisect.*detached HEAD" actual &&
+		test_grep "under-bisect.*detached HEAD" actual &&
 		test_must_fail git worktree add new-bisect under-bisect &&
 		test_path_is_missing new-bisect
 	)
diff --git a/t/t2402-worktree-list.sh b/t/t2402-worktree-list.sh
index 93f92e854a..eeaf800d74 100755
--- a/t/t2402-worktree-list.sh
+++ b/t/t2402-worktree-list.sh
@@ -101,8 +101,8 @@ test_expect_success '"list" all worktrees with locked annotation' '
 	git worktree lock locked &&
 	test_when_finished "git worktree unlock locked" &&
 	git worktree list >out &&
-	grep "/locked  *[0-9a-f].* locked$" out &&
-	! grep "/unlocked  *[0-9a-f].* locked$" out
+	test_grep "/locked  *[0-9a-f].* locked$" out &&
+	test_grep ! "/unlocked  *[0-9a-f].* locked$" out
 '
 
 test_expect_success '"list" all worktrees --porcelain with locked' '
@@ -143,8 +143,8 @@ test_expect_success '"list" all worktrees with prunable annotation' '
 	git worktree add --detach unprunable &&
 	rm -rf prunable &&
 	git worktree list >out &&
-	grep "/prunable  *[0-9a-f].* prunable$" out &&
-	! grep "/unprunable  *[0-9a-f].* prunable$" out
+	test_grep "/prunable  *[0-9a-f].* prunable$" out &&
+	test_grep ! "/unprunable  *[0-9a-f].* prunable$" out
 '
 
 test_expect_success '"list" all worktrees --porcelain with prunable' '
@@ -162,8 +162,8 @@ test_expect_success '"list" all worktrees with prunable consistent with "prune"'
 	git worktree add --detach unprunable &&
 	rm -rf prunable &&
 	git worktree list >out &&
-	grep "/prunable  *[0-9a-f].* prunable$" out &&
-	! grep "/unprunable  *[0-9a-f].* unprunable$" out &&
+	test_grep "/prunable  *[0-9a-f].* prunable$" out &&
+	test_grep ! "/unprunable  *[0-9a-f].* unprunable$" out &&
 	git worktree prune --verbose 2>out &&
 	test_grep "^Removing worktrees/prunable" out &&
 	test_grep ! "^Removing worktrees/unprunable" out
@@ -184,7 +184,7 @@ test_expect_success '"list" all worktrees --verbose with locked' '
 	echo "$(git -C locked2 rev-parse --show-toplevel) $(git rev-parse --short HEAD) (detached HEAD)" >expect &&
 	printf "\tlocked: with reason\n" >>expect &&
 	git worktree list --verbose >out &&
-	grep "/locked1  *[0-9a-f].* locked$" out &&
+	test_grep "/locked1  *[0-9a-f].* locked$" out &&
 	sed -n "s/  */ /g;/\/locked2  *[0-9a-f].*$/,/locked: .*$/p" <out >actual &&
 	test_cmp actual expect
 '
@@ -266,7 +266,7 @@ test_expect_success 'broken main worktree still at the top' '
 		test_cmp ../expected actual &&
 		git worktree list >out &&
 		head -n 1 out >actual.2 &&
-		grep -F "(error)" actual.2
+		test_grep -F "(error)" actual.2
 	)
 '
 
diff --git a/t/t2403-worktree-move.sh b/t/t2403-worktree-move.sh
index 0bb33e8b1b..69768c1207 100755
--- a/t/t2403-worktree-move.sh
+++ b/t/t2403-worktree-move.sh
@@ -75,8 +75,8 @@ test_expect_success 'move worktree' '
 	git worktree move source destination &&
 	test_path_is_missing source &&
 	git worktree list --porcelain >out &&
-	grep "^worktree.*/destination$" out &&
-	! grep "^worktree.*/source$" out &&
+	test_grep "^worktree.*/destination$" out &&
+	test_grep ! "^worktree.*/source$" out &&
 	git -C destination log --format=%s >actual2 &&
 	echo init >expected2 &&
 	test_cmp expected2 actual2
@@ -92,7 +92,7 @@ test_expect_success 'move worktree to another dir' '
 	test_when_finished "git worktree move some-dir/destination destination" &&
 	test_path_is_missing destination &&
 	git worktree list --porcelain >out &&
-	grep "^worktree.*/some-dir/destination$" out &&
+	test_grep "^worktree.*/some-dir/destination$" out &&
 	git -C some-dir/destination log --format=%s >actual2 &&
 	echo init >expected2 &&
 	test_cmp expected2 actual2
diff --git a/t/t2405-worktree-submodule.sh b/t/t2405-worktree-submodule.sh
index 11018f37c7..f5c94d490b 100755
--- a/t/t2405-worktree-submodule.sh
+++ b/t/t2405-worktree-submodule.sh
@@ -36,7 +36,7 @@ test_expect_success 'add superproject worktree' '
 
 test_expect_failure 'submodule is checked out just after worktree add' '
 	git -C worktree diff --submodule main"^!" >out &&
-	grep "file1 updated" out
+	test_grep "file1 updated" out
 '
 
 test_expect_success 'add superproject worktree and initialize submodules' '
@@ -46,7 +46,7 @@ test_expect_success 'add superproject worktree and initialize submodules' '
 
 test_expect_success 'submodule is checked out just after submodule update in linked worktree' '
 	git -C worktree-submodule-update diff --submodule main"^!" >out &&
-	grep "file1 updated" out
+	test_grep "file1 updated" out
 '
 
 test_expect_success 'add superproject worktree and manually add submodule worktree' '
@@ -56,7 +56,7 @@ test_expect_success 'add superproject worktree and manually add submodule worktr
 
 test_expect_success 'submodule is checked out after manually adding submodule worktree' '
 	git -C linked_submodule diff --submodule main"^!" >out &&
-	grep "file1 updated" out
+	test_grep "file1 updated" out
 '
 
 test_expect_success 'checkout --recurse-submodules uses $GIT_DIR for submodules in a linked worktree' '
diff --git a/t/t2407-worktree-heads.sh b/t/t2407-worktree-heads.sh
index 57c201869f..a6d7e0f83b 100755
--- a/t/t2407-worktree-heads.sh
+++ b/t/t2407-worktree-heads.sh
@@ -41,10 +41,10 @@ test_expect_success 'refuse to overwrite: checked out in worktree' '
 	for i in 1 2 3 4
 	do
 		test_must_fail git branch -f wt-$i HEAD 2>err &&
-		grep "cannot force update the branch" err &&
+		test_grep "cannot force update the branch" err &&
 
 		test_must_fail git branch -D wt-$i 2>err &&
-		grep "cannot delete branch" err || return 1
+		test_grep "cannot delete branch" err || return 1
 	done
 '
 
@@ -57,7 +57,7 @@ test_expect_success 'refuse to overwrite: worktree in bisect' '
 	git -C wt-4 bisect good wt-1 &&
 
 	test_must_fail git branch -f wt-4 HEAD 2>err &&
-	grep "cannot force update the branch '\''wt-4'\'' used by worktree at.*wt-4" err
+	test_grep "cannot force update the branch '\''wt-4'\'' used by worktree at.*wt-4" err
 '
 
 test_expect_success 'refuse to overwrite: worktree in rebase (apply)' '
@@ -67,7 +67,7 @@ test_expect_success 'refuse to overwrite: worktree in rebase (apply)' '
 	test_must_fail git -C wt-2 rebase --apply conflict-2 &&
 
 	test_must_fail git branch -f wt-2 HEAD 2>err &&
-	grep "cannot force update the branch '\''wt-2'\'' used by worktree at.*wt-2" err
+	test_grep "cannot force update the branch '\''wt-2'\'' used by worktree at.*wt-2" err
 '
 
 test_expect_success 'refuse to overwrite: worktree in rebase (merge)' '
@@ -77,7 +77,7 @@ test_expect_success 'refuse to overwrite: worktree in rebase (merge)' '
 	test_must_fail git -C wt-2 rebase conflict-2 &&
 
 	test_must_fail git branch -f wt-2 HEAD 2>err &&
-	grep "cannot force update the branch '\''wt-2'\'' used by worktree at.*wt-2" err
+	test_grep "cannot force update the branch '\''wt-2'\'' used by worktree at.*wt-2" err
 '
 
 test_expect_success 'refuse to overwrite: worktree in rebase with --update-refs' '
@@ -89,19 +89,19 @@ test_expect_success 'refuse to overwrite: worktree in rebase with --update-refs'
 	for i in 3 4
 	do
 		test_must_fail git branch -f can-be-updated HEAD 2>err &&
-		grep "cannot force update the branch '\''can-be-updated'\'' used by worktree at.*wt-3" err ||
+		test_grep "cannot force update the branch '\''can-be-updated'\'' used by worktree at.*wt-3" err ||
 			return 1
 	done
 '
 
 test_expect_success 'refuse to fetch over ref: checked out' '
 	test_must_fail git fetch server +refs/heads/wt-3:refs/heads/wt-3 2>err &&
-	grep "refusing to fetch into branch '\''refs/heads/wt-3'\''" err &&
+	test_grep "refusing to fetch into branch '\''refs/heads/wt-3'\''" err &&
 
 	# General fetch into refs/heads/ will fail on first ref,
 	# so use a generic error message check.
 	test_must_fail git fetch server +refs/heads/*:refs/heads/* 2>err &&
-	grep "refusing to fetch into branch" err
+	test_grep "refusing to fetch into branch" err
 '
 
 test_expect_success 'refuse to fetch over ref: worktree in bisect' '
@@ -113,7 +113,7 @@ test_expect_success 'refuse to fetch over ref: worktree in bisect' '
 	git -C wt-4 bisect good wt-1 &&
 
 	test_must_fail git fetch server +refs/heads/wt-4:refs/heads/wt-4 2>err &&
-	grep "refusing to fetch into branch" err
+	test_grep "refusing to fetch into branch" err
 '
 
 test_expect_success 'refuse to fetch over ref: worktree in rebase' '
@@ -123,7 +123,7 @@ test_expect_success 'refuse to fetch over ref: worktree in rebase' '
 	test_must_fail git -C wt-3 rebase conflict-3 &&
 
 	test_must_fail git fetch server +refs/heads/wt-3:refs/heads/wt-3 2>err &&
-	grep "refusing to fetch into branch" err
+	test_grep "refusing to fetch into branch" err
 '
 
 test_expect_success 'refuse to overwrite when in error states' '
@@ -149,7 +149,7 @@ test_expect_success 'refuse to overwrite when in error states' '
 	for i in 1 2
 	do
 		test_must_fail git branch -f fake-$i HEAD 2>err &&
-		grep "cannot force update the branch '\''fake-$i'\'' used by worktree at" err ||
+		test_grep "cannot force update the branch '\''fake-$i'\'' used by worktree at" err ||
 			return 1
 	done
 '
@@ -161,13 +161,13 @@ test_expect_success 'refuse to overwrite during rebase with --update-refs' '
 	(
 		set_cat_todo_editor &&
 		test_must_fail git rebase -i --update-refs HEAD~3 >todo &&
-		! grep "update-refs" todo
+		test_grep ! "update-refs" todo
 	) &&
 	git branch -f allow-update HEAD~2 &&
 	(
 		set_cat_todo_editor &&
 		test_must_fail git rebase -i --update-refs HEAD~3 >todo &&
-		grep "update-ref refs/heads/allow-update" todo
+		test_grep "update-ref refs/heads/allow-update" todo
 	)
 '
 
diff --git a/t/t2500-untracked-overwriting.sh b/t/t2500-untracked-overwriting.sh
index 5c0bf4d21f..8e84f29e8d 100755
--- a/t/t2500-untracked-overwriting.sh
+++ b/t/t2500-untracked-overwriting.sh
@@ -51,7 +51,7 @@ test_expect_success 'reset --merge will preserve untracked files/dirs' '
 
 		test_must_fail git reset --merge work 2>error &&
 		test_cmp expect foo.t/file &&
-		grep "Updating .foo.t. would lose untracked files" error
+		test_grep "Updating .foo.t. would lose untracked files" error
 	)
 '
 
@@ -66,7 +66,7 @@ test_expect_success 'reset --keep will preserve untracked files/dirs' '
 
 		test_must_fail git reset --merge work 2>error &&
 		test_cmp expect foo.t/file &&
-		grep "Updating.*foo.t.*would lose untracked files" error
+		test_grep "Updating.*foo.t.*would lose untracked files" error
 	)
 '
 
@@ -214,7 +214,7 @@ test_expect_success 'git am --abort and untracked dir vs. unmerged file' '
 
 		test_must_fail git am --abort 2>errors &&
 		test_path_is_dir filler &&
-		grep "Updating .filler. would lose untracked files in it" errors
+		test_grep "Updating .filler. would lose untracked files in it" errors
 	)
 '
 
@@ -237,7 +237,7 @@ test_expect_success 'git am --skip and untracked dir vs deleted file' '
 		# Change our mind about resolutions, just skip this patch
 		test_must_fail git am --skip 2>errors &&
 		test_path_is_dir newfile &&
-		grep "Updating .newfile. would lose untracked files in it" errors
+		test_grep "Updating .newfile. would lose untracked files in it" errors
 	)
 '
 
diff --git a/t/t2501-cwd-empty.sh b/t/t2501-cwd-empty.sh
index be9140bbaa..eb6451d71d 100755
--- a/t/t2501-cwd-empty.sh
+++ b/t/t2501-cwd-empty.sh
@@ -114,7 +114,7 @@ test_expect_success 'merge fails if cwd needs to be removed; recursive friendly'
 	) &&
 
 	test_path_is_dir dirORfile &&
-	grep "Refusing to remove the current working directory" error
+	test_grep "Refusing to remove the current working directory" error
 '
 
 test_expect_success 'merge fails if cwd needs to be removed' '
@@ -179,7 +179,7 @@ test_incidental_untracked_dir_removal () {
 test_expect_success 'clean does not remove cwd incidentally' '
 	test_incidental_untracked_dir_removal \
 		git -C .. clean -fd -e warnings . >warnings &&
-	grep "Refusing to remove current working directory" warnings
+	test_grep "Refusing to remove current working directory" warnings
 '
 
 test_expect_success 'stash does not remove cwd incidentally' '
diff --git a/t/t3001-ls-files-others-exclude.sh b/t/t3001-ls-files-others-exclude.sh
index 202fb8d9ea..29a0a25b30 100755
--- a/t/t3001-ls-files-others-exclude.sh
+++ b/t/t3001-ls-files-others-exclude.sh
@@ -161,21 +161,21 @@ test_expect_success 'trailing slash in exclude forces directory match (1)' '
 
 	>two &&
 	git ls-files --others --exclude=two/ >output &&
-	grep "^two" output
+	test_grep "^two" output
 
 '
 
 test_expect_success 'trailing slash in exclude forces directory match (2)' '
 
 	git ls-files --others --exclude=one/a.1/ >output &&
-	grep "^one/a.1" output
+	test_grep "^one/a.1" output
 
 '
 
 test_expect_success 'negated exclude matches can override previous ones' '
 
 	git ls-files --others --exclude="a.*" --exclude="!a.1" >output &&
-	grep "^a.1" output
+	test_grep "^a.1" output
 '
 
 test_expect_success 'excluded directory overrides content patterns' '
diff --git a/t/t3007-ls-files-recurse-submodules.sh b/t/t3007-ls-files-recurse-submodules.sh
index 61771eec83..218964edab 100755
--- a/t/t3007-ls-files-recurse-submodules.sh
+++ b/t/t3007-ls-files-recurse-submodules.sh
@@ -302,7 +302,7 @@ test_expect_success '--recurse-submodules does not support --error-unmatch' '
 test_expect_success '--recurse-submodules parses submodule repo config' '
 	test_config -C submodule index.sparse "invalid non-boolean value" &&
 	test_must_fail git ls-files --recurse-submodules 2>err &&
-	grep "bad boolean config value" err
+	test_grep "bad boolean config value" err
 '
 
 test_expect_success '--recurse-submodules parses submodule worktree config' '
@@ -310,7 +310,7 @@ test_expect_success '--recurse-submodules parses submodule worktree config' '
 	test_config -C submodule --worktree index.sparse "invalid non-boolean value" &&
 
 	test_must_fail git ls-files --recurse-submodules 2>err &&
-	grep "bad boolean config value" err
+	test_grep "bad boolean config value" err
 '
 
 test_expect_success '--recurse-submodules submodules ignore super project worktreeConfig extension' '
@@ -329,7 +329,7 @@ test_expect_success '--recurse-submodules submodules ignore super project worktr
 	# With extensions.worktreeConfig disabled in the submodule, the invalid
 	# worktree config is not picked up.
 	git ls-files --recurse-submodules 2>err &&
-	! grep "bad boolean config value" err
+	test_grep ! "bad boolean config value" err
 '
 
 test_incompatible_with_recurse_submodules () {
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index e7829c2c4b..bd839998b1 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -204,7 +204,7 @@ test_expect_success 'git branch -M baz bam should succeed when baz is checked ou
 
 test_expect_success 'git branch -M baz bam should add entries to HEAD reflog' '
 	git reflog show HEAD >actual &&
-	grep "HEAD@{0}: Branch: renamed refs/heads/baz to refs/heads/bam" actual
+	test_grep "HEAD@{0}: Branch: renamed refs/heads/baz to refs/heads/bam" actual
 '
 
 test_expect_success 'git branch -M should leave orphaned HEAD alone' '
@@ -339,7 +339,7 @@ test_expect_success 'git branch -d on orphan HEAD (unmerged)' '
 	test_when_finished "git branch -D to-delete" &&
 	git branch to-delete main &&
 	test_must_fail git branch -d to-delete 2>err &&
-	grep "not fully merged" err
+	test_grep "not fully merged" err
 '
 
 test_expect_success 'git branch -d on orphan HEAD (unmerged, graph)' '
@@ -350,7 +350,7 @@ test_expect_success 'git branch -d on orphan HEAD (unmerged, graph)' '
 	test_when_finished "rm -rf .git/objects/commit-graph*" &&
 	git commit-graph write --reachable &&
 	test_must_fail git branch -d to-delete 2>err &&
-	grep "not fully merged" err
+	test_grep "not fully merged" err
 '
 
 test_expect_success 'git branch -v -d t should work' '
@@ -712,7 +712,7 @@ test_expect_success 'git branch -C c1 c2 should succeed when c1 is checked out'
 test_expect_success 'git branch -C c1 c2 should never touch HEAD' '
 	msg="Branch: copied refs/heads/c1 to refs/heads/c2" &&
 	git reflog HEAD >actual &&
-	! grep "$msg$" actual
+	test_grep ! "$msg$" actual
 '
 
 test_expect_success 'git branch -C main should work when main is checked out' '
@@ -930,7 +930,7 @@ test_expect_success 'deleting currently checked out branch fails' '
 	git worktree add -b my7 my7 &&
 	test_must_fail git -C my7 branch -d my7 &&
 	test_must_fail git branch -d my7 2>actual &&
-	grep "^error: cannot delete branch .my7. used by worktree at " actual &&
+	test_grep "^error: cannot delete branch .my7. used by worktree at " actual &&
 	rm -r my7 &&
 	git worktree prune
 '
@@ -941,7 +941,7 @@ test_expect_success 'deleting in-use branch fails' '
 	git -C my7 bisect start HEAD HEAD~2 &&
 	test_must_fail git -C my7 branch -d my7 &&
 	test_must_fail git branch -d my7 2>actual &&
-	grep "^error: cannot delete branch .my7. used by worktree at " actual &&
+	test_grep "^error: cannot delete branch .my7. used by worktree at " actual &&
 	rm -r my7 &&
 	git worktree prune
 '
diff --git a/t/t3202-show-branch.sh b/t/t3202-show-branch.sh
index a1139f79e2..f402334936 100755
--- a/t/t3202-show-branch.sh
+++ b/t/t3202-show-branch.sh
@@ -123,13 +123,13 @@ test_expect_success 'show-branch --sparse' '
 	git commit --allow-empty -m "another" &&
 
 	git show-branch --sparse >out &&
-	grep "merge 1 and 10 to make A" out &&
+	test_grep "merge 1 and 10 to make A" out &&
 
 	git show-branch >out &&
-	! grep "merge 1 and 10 to make A" out &&
+	test_grep ! "merge 1 and 10 to make A" out &&
 
 	git show-branch --no-sparse >out &&
-	! grep "merge 1 and 10 to make A" out
+	test_grep ! "merge 1 and 10 to make A" out
 '
 
 test_expect_success 'setup show branch --list' '
@@ -189,7 +189,7 @@ while read combo
 do
 	test_expect_success "show-branch $combo (should fail)" '
 		test_must_fail git show-branch $combo 2>error &&
-		grep -e "cannot be used together" -e "usage:" error
+		test_grep -e "cannot be used together" -e "usage:" error
 	'
 done <<\EOF
 --all --reflog
@@ -203,7 +203,7 @@ for opt in topo-order date-order reflog
 do
 	test_expect_success "show-branch --no-$opt (should fail)" '
 		test_must_fail git show-branch --no-$opt 2>err &&
-		grep "unknown option .no-$opt." err
+		test_grep "unknown option .no-$opt." err
 	'
 done
 
diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index a6bd88a58d..7c44186341 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -64,7 +64,7 @@ test_expect_success 'git branch -r shows remote branches' '
 
 test_expect_success 'git branch --no-remotes is rejected' '
 	test_must_fail git branch --no-remotes 2>err &&
-	grep "unknown option .no-remotes." err
+	test_grep "unknown option .no-remotes." err
 '
 
 cat >expect <<'EOF'
@@ -85,7 +85,7 @@ test_expect_success 'git branch -a shows local and remote branches' '
 
 test_expect_success 'git branch --no-all is rejected' '
 	test_must_fail git branch --no-all 2>err &&
-	grep "unknown option .no-all." err
+	test_grep "unknown option .no-all." err
 '
 
 cat >expect <<'EOF'
diff --git a/t/t3206-range-diff.sh b/t/t3206-range-diff.sh
index 1e812df806..ef92704de3 100755
--- a/t/t3206-range-diff.sh
+++ b/t/t3206-range-diff.sh
@@ -538,10 +538,10 @@ do
 			main..unmodified >actual &&
 		test_line_count = 5 actual &&
 		test_grep "^Range-diff:$" 0000-* &&
-		grep "= 1: .* s/5/A" 0000-* &&
-		grep "= 2: .* s/4/A" 0000-* &&
-		grep "= 3: .* s/11/B" 0000-* &&
-		grep "= 4: .* s/12/B" 0000-*
+		test_grep "= 1: .* s/5/A" 0000-* &&
+		test_grep "= 2: .* s/4/A" 0000-* &&
+		test_grep "= 3: .* s/11/B" 0000-* &&
+		test_grep "= 4: .* s/12/B" 0000-*
 	'
 done
 
@@ -564,7 +564,7 @@ test_expect_success 'format-patch --range-diff as commentary' '
 	git format-patch --range-diff=HEAD~1 HEAD~1 >actual &&
 	test_line_count = 1 actual &&
 	test_grep "^Range-diff:$" 0001-* &&
-	grep "> 1: .* new message" 0001-*
+	test_grep "> 1: .* new message" 0001-*
 '
 
 test_expect_success 'format-patch --range-diff reroll-count with a non-integer' '
@@ -572,7 +572,7 @@ test_expect_success 'format-patch --range-diff reroll-count with a non-integer'
 	git format-patch --range-diff=HEAD~1 -v2.9 HEAD~1 >actual &&
 	test_line_count = 1 actual &&
 	test_grep "^Range-diff:$" v2.9-0001-* &&
-	grep "> 1: .* new message" v2.9-0001-*
+	test_grep "> 1: .* new message" v2.9-0001-*
 '
 
 test_expect_success 'format-patch --range-diff reroll-count with a integer' '
@@ -580,7 +580,7 @@ test_expect_success 'format-patch --range-diff reroll-count with a integer' '
 	git format-patch --range-diff=HEAD~1 -v2 HEAD~1 >actual &&
 	test_line_count = 1 actual &&
 	test_grep "^Range-diff ..* v1:$" v2-0001-* &&
-	grep "> 1: .* new message" v2-0001-*
+	test_grep "> 1: .* new message" v2-0001-*
 '
 
 test_expect_success 'format-patch --range-diff with v0' '
@@ -588,7 +588,7 @@ test_expect_success 'format-patch --range-diff with v0' '
 	git format-patch --range-diff=HEAD~1 -v0 HEAD~1 >actual &&
 	test_line_count = 1 actual &&
 	test_grep "^Range-diff:$" v0-0001-* &&
-	grep "> 1: .* new message" v0-0001-*
+	test_grep "> 1: .* new message" v0-0001-*
 '
 
 test_expect_success 'range-diff overrides diff.noprefix internally' '
@@ -686,8 +686,8 @@ test_expect_success 'range-diff with --notes=custom does not show default notes'
 	git notes --ref=custom add -m "unmodified note" unmodified &&
 	git range-diff --notes=custom main..topic main..unmodified \
 		>actual &&
-	! grep "## Notes ##" actual &&
-	grep "## Notes (custom) ##" actual
+	test_grep ! "## Notes ##" actual &&
+	test_grep "## Notes (custom) ##" actual
 '
 
 test_expect_success 'format-patch --range-diff does not compare notes by default' '
@@ -699,12 +699,12 @@ test_expect_success 'format-patch --range-diff does not compare notes by default
 		main..unmodified >actual &&
 	test_line_count = 5 actual &&
 	test_grep "^Range-diff:$" 0000-* &&
-	grep "= 1: .* s/5/A" 0000-* &&
-	grep "= 2: .* s/4/A" 0000-* &&
-	grep "= 3: .* s/11/B" 0000-* &&
-	grep "= 4: .* s/12/B" 0000-* &&
-	! grep "Notes" 0000-* &&
-	! grep "note" 0000-*
+	test_grep "= 1: .* s/5/A" 0000-* &&
+	test_grep "= 2: .* s/4/A" 0000-* &&
+	test_grep "= 3: .* s/11/B" 0000-* &&
+	test_grep "= 4: .* s/12/B" 0000-* &&
+	test_grep ! "Notes" 0000-* &&
+	test_grep ! "note" 0000-*
 '
 
 test_expect_success 'format-patch --notes=custom --range-diff --cover-letter only compares custom notes' '
@@ -717,8 +717,8 @@ test_expect_success 'format-patch --notes=custom --range-diff --cover-letter onl
 	test_when_finished "rm -f 000?-*" &&
 	git format-patch --notes=custom --cover-letter --range-diff=$prev \
 		main..unmodified >actual &&
-	grep "## Notes (custom) ##" 0000-* &&
-	! grep "## Notes ##" 0000-*
+	test_grep "## Notes (custom) ##" 0000-* &&
+	test_grep ! "## Notes ##" 0000-*
 '
 
 # --range-diff on a single commit requires --no-cover-letter
@@ -744,12 +744,12 @@ test_expect_success 'format-patch --range-diff with --no-notes' '
 		main..unmodified >actual &&
 	test_line_count = 5 actual &&
 	test_grep "^Range-diff:$" 0000-* &&
-	grep "= 1: .* s/5/A" 0000-* &&
-	grep "= 2: .* s/4/A" 0000-* &&
-	grep "= 3: .* s/11/B" 0000-* &&
-	grep "= 4: .* s/12/B" 0000-* &&
-	! grep "Notes" 0000-* &&
-	! grep "note" 0000-*
+	test_grep "= 1: .* s/5/A" 0000-* &&
+	test_grep "= 2: .* s/4/A" 0000-* &&
+	test_grep "= 3: .* s/11/B" 0000-* &&
+	test_grep "= 4: .* s/12/B" 0000-* &&
+	test_grep ! "Notes" 0000-* &&
+	test_grep ! "note" 0000-*
 '
 
 test_expect_success 'format-patch --range-diff with --notes' '
@@ -761,10 +761,10 @@ test_expect_success 'format-patch --range-diff with --notes' '
 		main..unmodified >actual &&
 	test_line_count = 5 actual &&
 	test_grep "^Range-diff:$" 0000-* &&
-	grep "= 1: .* s/5/A" 0000-* &&
-	grep "= 2: .* s/4/A" 0000-* &&
-	grep "= 3: .* s/11/B" 0000-* &&
-	grep "! 4: .* s/12/B" 0000-* &&
+	test_grep "= 1: .* s/5/A" 0000-* &&
+	test_grep "= 2: .* s/4/A" 0000-* &&
+	test_grep "= 3: .* s/11/B" 0000-* &&
+	test_grep "! 4: .* s/12/B" 0000-* &&
 	sed s/Z/\ /g >expect <<-EOF &&
 	    @@ Commit message
 	    Z
@@ -790,10 +790,10 @@ test_expect_success 'format-patch --range-diff with format.notes config' '
 		main..unmodified >actual &&
 	test_line_count = 5 actual &&
 	test_grep "^Range-diff:$" 0000-* &&
-	grep "= 1: .* s/5/A" 0000-* &&
-	grep "= 2: .* s/4/A" 0000-* &&
-	grep "= 3: .* s/11/B" 0000-* &&
-	grep "! 4: .* s/12/B" 0000-* &&
+	test_grep "= 1: .* s/5/A" 0000-* &&
+	test_grep "= 2: .* s/4/A" 0000-* &&
+	test_grep "= 3: .* s/11/B" 0000-* &&
+	test_grep "! 4: .* s/12/B" 0000-* &&
 	sed s/Z/\ /g >expect <<-EOF &&
 	    @@ Commit message
 	    Z
@@ -821,10 +821,10 @@ test_expect_success 'format-patch --range-diff with multiple notes' '
 		main..unmodified >actual &&
 	test_line_count = 5 actual &&
 	test_grep "^Range-diff:$" 0000-* &&
-	grep "= 1: .* s/5/A" 0000-* &&
-	grep "= 2: .* s/4/A" 0000-* &&
-	grep "= 3: .* s/11/B" 0000-* &&
-	grep "! 4: .* s/12/B" 0000-* &&
+	test_grep "= 1: .* s/5/A" 0000-* &&
+	test_grep "= 2: .* s/4/A" 0000-* &&
+	test_grep "= 3: .* s/11/B" 0000-* &&
+	test_grep "! 4: .* s/12/B" 0000-* &&
 	sed s/Z/\ /g >expect <<-EOF &&
 	    @@ Commit message
 	    Z
@@ -866,9 +866,9 @@ test_expect_success 'ranges with pathspecs' '
 	topic_oid=$(git rev-parse --short topic) &&
 	mode_change_oid=$(git rev-parse --short mode-only-change^) &&
 	file_change_oid=$(git rev-parse --short mode-only-change) &&
-	grep "$mode_change_oid" actual &&
-	! grep "$file_change_oid" actual &&
-	! grep "$topic_oid" actual
+	test_grep "$mode_change_oid" actual &&
+	test_grep ! "$file_change_oid" actual &&
+	test_grep ! "$topic_oid" actual
 '
 
 test_expect_success 'submodule changes are shown irrespective of diff.submodule' '
diff --git a/t/t3207-branch-submodule.sh b/t/t3207-branch-submodule.sh
index fe72b24716..4afb2d3198 100755
--- a/t/t3207-branch-submodule.sh
+++ b/t/t3207-branch-submodule.sh
@@ -136,7 +136,7 @@ test_expect_success 'should not create any branches if branch is not valid for a
 		git -C sub branch branch-a &&
 		test_must_fail git branch --recurse-submodules branch-a 2>actual &&
 		test_no_branch . branch-a &&
-		grep "submodule .sub.: fatal: a branch named .branch-a. already exists" actual
+		test_grep "submodule .sub.: fatal: a branch named .branch-a. already exists" actual
 	)
 '
 
@@ -251,7 +251,7 @@ test_expect_success 'should get fatal error upon branch creation when submodule
 		git branch --recurse-submodules branch-a origin/branch-a &&
 		# This should fail because super-clone does not have sub2 .git/modules
 		test_must_fail git branch --recurse-submodules branch-b origin/branch-b 2>actual &&
-		grep "fatal: submodule .sub2.: unable to find submodule" actual &&
+		test_grep "fatal: submodule .sub2.: unable to find submodule" actual &&
 		test_no_branch . branch-b &&
 		test_no_branch sub branch-b &&
 		# User can fix themselves by initializing the submodule
diff --git a/t/t3301-notes.sh b/t/t3301-notes.sh
index d6c50460d0..18a6000171 100755
--- a/t/t3301-notes.sh
+++ b/t/t3301-notes.sh
@@ -164,7 +164,7 @@ test_expect_success 'show notes' '
 		${indent}b1
 	EOF
 	git cat-file commit HEAD >commits &&
-	! grep b1 commits &&
+	test_grep ! b1 commits &&
 	git log -1 >actual &&
 	test_cmp expect actual
 '
@@ -248,17 +248,17 @@ test_expect_success 'git log --show-notes' '
 
 test_expect_success 'git log --no-notes' '
 	git log -1 --no-notes >actual &&
-	! grep xyzzy actual
+	test_grep ! xyzzy actual
 '
 
 test_expect_success 'git format-patch does not show notes' '
 	git format-patch -1 --stdout >actual &&
-	! grep xyzzy actual
+	test_grep ! xyzzy actual
 '
 
 test_expect_success 'git format-patch --show-notes does show notes' '
 	git format-patch --show-notes -1 --stdout >actual &&
-	grep xyzzy actual
+	test_grep xyzzy actual
 '
 
 for pretty in \
@@ -281,36 +281,36 @@ test_expect_success 'setup alternate notes ref' '
 
 test_expect_success 'git log --notes shows default notes' '
 	git log -1 --notes >actual &&
-	grep xyzzy actual &&
-	! grep alternate actual
+	test_grep xyzzy actual &&
+	test_grep ! alternate actual
 '
 
 test_expect_success 'git log --notes=X shows only X' '
 	git log -1 --notes=alternate >actual &&
-	! grep xyzzy actual &&
-	grep alternate actual
+	test_grep ! xyzzy actual &&
+	test_grep alternate actual
 '
 
 test_expect_success 'git log --notes --notes=X shows both' '
 	git log -1 --notes --notes=alternate >actual &&
-	grep xyzzy actual &&
-	grep alternate actual
+	test_grep xyzzy actual &&
+	test_grep alternate actual
 '
 
 test_expect_success 'git log --no-notes resets default state' '
 	git log -1 --notes --notes=alternate \
 		--no-notes --notes=alternate \
 		>actual &&
-	! grep xyzzy actual &&
-	grep alternate actual
+	test_grep ! xyzzy actual &&
+	test_grep alternate actual
 '
 
 test_expect_success 'git log --no-notes resets ref list' '
 	git log -1 --notes --notes=alternate \
 		--no-notes --notes \
 		>actual &&
-	grep xyzzy actual &&
-	! grep alternate actual
+	test_grep xyzzy actual &&
+	test_grep ! alternate actual
 '
 
 test_expect_success 'show -m notes' '
@@ -543,7 +543,7 @@ test_expect_success 'list notes with "git notes"' '
 
 test_expect_success '"git notes" without subcommand does not take arguments' '
 	test_expect_code 129 git notes HEAD^^ 2>err &&
-	grep "^error: unknown subcommand" err
+	test_grep "^error: unknown subcommand" err
 '
 
 test_expect_success 'list specific note with "git notes list <object>"' '
@@ -1464,7 +1464,7 @@ test_expect_success 'GIT_NOTES_REWRITE_REF overrides config' '
 	GIT_NOTES_REWRITE_REF=refs/notes/commits \
 		git notes copy --for-rewrite=foo <copy &&
 	git log -1 >actual &&
-	grep "replacement note 3" actual
+	test_grep "replacement note 3" actual
 '
 
 test_expect_success 'git notes copy diagnoses too many or too few arguments' '
diff --git a/t/t3310-notes-merge-manual-resolve.sh b/t/t3310-notes-merge-manual-resolve.sh
index 0bb366fdb8..caa1bf250b 100755
--- a/t/t3310-notes-merge-manual-resolve.sh
+++ b/t/t3310-notes-merge-manual-resolve.sh
@@ -382,12 +382,12 @@ EOF
 	test_cmp pre_merge_z actual &&
 	# Merge commit mentions the notes refs merged
 	git log -1 --format=%B refs/notes/m > merge_commit_msg &&
-	grep -q refs/notes/m merge_commit_msg &&
-	grep -q refs/notes/z merge_commit_msg &&
+	test_grep refs/notes/m merge_commit_msg &&
+	test_grep refs/notes/z merge_commit_msg &&
 	# Merge commit mentions conflicting notes
-	grep -q "Conflicts" merge_commit_msg &&
+	test_grep "Conflicts" merge_commit_msg &&
 	( for sha1 in $(cat expect_conflicts); do
-		grep -q "$sha1" merge_commit_msg ||
+		test_grep "$sha1" merge_commit_msg ||
 		exit 1
 	done ) &&
 	# Verify contents of merge result
@@ -512,12 +512,12 @@ EOF
 	test_cmp pre_merge_z actual &&
 	# Merge commit mentions the notes refs merged
 	git log -1 --format=%B refs/notes/m > merge_commit_msg &&
-	grep -q refs/notes/m merge_commit_msg &&
-	grep -q refs/notes/z merge_commit_msg &&
+	test_grep refs/notes/m merge_commit_msg &&
+	test_grep refs/notes/z merge_commit_msg &&
 	# Merge commit mentions conflicting notes
-	grep -q "Conflicts" merge_commit_msg &&
+	test_grep "Conflicts" merge_commit_msg &&
 	( for sha1 in $(cat expect_conflicts); do
-		grep -q "$sha1" merge_commit_msg ||
+		test_grep "$sha1" merge_commit_msg ||
 		exit 1
 	done ) &&
 	# Verify contents of merge result
diff --git a/t/t3320-notes-merge-worktrees.sh b/t/t3320-notes-merge-worktrees.sh
index 96243b7222..9a2c3ac3f7 100755
--- a/t/t3320-notes-merge-worktrees.sh
+++ b/t/t3320-notes-merge-worktrees.sh
@@ -67,7 +67,7 @@ test_expect_success 'merge z into x while mid-merge on y succeeds' '
 		git config core.notesRef refs/notes/x &&
 		test_must_fail git notes merge z >out 2>&1 &&
 		test_grep "Automatic notes merge failed" out &&
-		grep -v "A notes merge into refs/notes/x is already in-progress in" out
+		test_grep -v "A notes merge into refs/notes/x is already in-progress in" out
 	) &&
 	echo "refs/notes/x" >expect &&
 	git -C worktree2 symbolic-ref NOTES_MERGE_REF >actual &&
diff --git a/t/t3400-rebase.sh b/t/t3400-rebase.sh
index c0c00fbb7b..e62e07b894 100755
--- a/t/t3400-rebase.sh
+++ b/t/t3400-rebase.sh
@@ -287,16 +287,16 @@ test_expect_success 'rebase commit with an ancient timestamp' '
 	git commit --date="@34567 +0600" -m "Old three" &&
 
 	git cat-file commit HEAD^^ >actual &&
-	grep "author .* 12345 +0400$" actual &&
+	test_grep "author .* 12345 +0400$" actual &&
 	git cat-file commit HEAD^ >actual &&
-	grep "author .* 23456 +0500$" actual &&
+	test_grep "author .* 23456 +0500$" actual &&
 	git cat-file commit HEAD >actual &&
-	grep "author .* 34567 +0600$" actual &&
+	test_grep "author .* 34567 +0600$" actual &&
 
 	git rebase --onto HEAD^^ HEAD^ &&
 
 	git cat-file commit HEAD >actual &&
-	grep "author .* 34567 +0600$" actual
+	test_grep "author .* 34567 +0600$" actual
 '
 
 test_expect_success 'rebase with "From " line in commit message' '
@@ -333,7 +333,7 @@ test_expect_success 'rebase --apply and --show-current-patch' '
 		git tag two &&
 		test_must_fail git rebase --apply -f --onto init HEAD^ &&
 		GIT_TRACE=1 git rebase --show-current-patch >/dev/null 2>stderr &&
-		grep "show.*$(git rev-parse two)" stderr
+		test_grep "show.*$(git rev-parse two)" stderr
 	)
 '
 
@@ -364,12 +364,12 @@ test_expect_success 'rebase --apply and .gitattributes' '
 
 		git checkout test &&
 		git rebase main &&
-		grep "smudged" a.txt &&
+		test_grep "smudged" a.txt &&
 
 		git checkout removal &&
 		git reset --hard &&
 		git rebase main &&
-		grep "clean" a.txt
+		test_grep "clean" a.txt
 	)
 '
 
@@ -386,7 +386,7 @@ test_expect_success 'rebase--merge.sh and --show-current-patch' '
 		test_must_fail git rebase --merge --onto init HEAD^ &&
 		git rebase --show-current-patch >actual.patch &&
 		GIT_TRACE=1 git rebase --show-current-patch >/dev/null 2>stderr &&
-		grep "show.*REBASE_HEAD" stderr &&
+		test_grep "show.*REBASE_HEAD" stderr &&
 		test "$(git rev-parse REBASE_HEAD)" = "$(git rev-parse two)"
 	)
 '
diff --git a/t/t3402-rebase-merge.sh b/t/t3402-rebase-merge.sh
index 761de63b6b..41ebcdec9f 100755
--- a/t/t3402-rebase-merge.sh
+++ b/t/t3402-rebase-merge.sh
@@ -84,8 +84,8 @@ test_expect_success 'rebase -Xtheirs' '
 	echo "AB $T" >> original &&
 	git commit -mconflicting original &&
 	git rebase -Xtheirs main &&
-	grep AB original &&
-	! grep 11 original
+	test_grep AB original &&
+	test_grep ! 11 original
 '
 
 test_expect_success 'rebase -Xtheirs from orphan' '
@@ -93,8 +93,8 @@ test_expect_success 'rebase -Xtheirs from orphan' '
 	echo "AB $T" >> original &&
 	git commit -morphan-conflicting original &&
 	git rebase -Xtheirs main &&
-	grep AB original &&
-	! grep 11 original
+	test_grep AB original &&
+	test_grep ! 11 original
 '
 
 test_expect_success 'merge and rebase should match' '
@@ -210,15 +210,15 @@ test_expect_success '--reapply-cherry-picks refrains from reading unneeded blobs
 	git -C client rev-list --objects --all --missing=print >missing_list &&
 	MERGE_BASE_BLOB=$(git -C server rev-parse main^^:file.txt) &&
 	ADD_11_BLOB=$(git -C server rev-parse main^:file.txt) &&
-	grep "[?]$MERGE_BASE_BLOB" missing_list &&
-	grep "[?]$ADD_11_BLOB" missing_list &&
+	test_grep "[?]$MERGE_BASE_BLOB" missing_list &&
+	test_grep "[?]$ADD_11_BLOB" missing_list &&
 
 	git -C client rebase --merge --reapply-cherry-picks origin/main &&
 
 	# The blob from the merge base had to be fetched, but not "add 11"
 	git -C client rev-list --objects --all --missing=print >missing_list &&
-	! grep "[?]$MERGE_BASE_BLOB" missing_list &&
-	grep "[?]$ADD_11_BLOB" missing_list
+	test_grep ! "[?]$MERGE_BASE_BLOB" missing_list &&
+	test_grep "[?]$ADD_11_BLOB" missing_list
 '
 
 test_done
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 58b3bb0c27..a11c6d3714 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -144,7 +144,7 @@ test_expect_success 'rebase -i sets work tree properly' '
 	mkdir subdir &&
 	git rebase -x "(cd subdir && git rev-parse --show-toplevel)" HEAD^ \
 		>actual &&
-	! grep "/subdir$" actual
+	test_grep ! "/subdir$" actual
 '
 
 test_expect_success 'rebase -i with the exec command checks tree cleanness' '
@@ -196,7 +196,7 @@ test_expect_success 'rebase -i with exec of inexistent command' '
 		test_must_fail env FAKE_LINES="exec_this-command-does-not-exist 1" \
 			git rebase -i HEAD^ >actual 2>&1
 	) &&
-	! grep "Maybe git-rebase is broken" actual
+	test_grep ! "Maybe git-rebase is broken" actual
 '
 
 test_expect_success 'implicit interactive rebase does not invoke sequence editor' '
@@ -293,7 +293,7 @@ test_expect_success 'stop on conflicting pick' '
 
 test_expect_success 'show conflicted patch' '
 	GIT_TRACE=1 git rebase --show-current-patch >/dev/null 2>stderr &&
-	grep "show.*REBASE_HEAD" stderr &&
+	test_grep "show.*REBASE_HEAD" stderr &&
 	# the original stopped-sha1 is abbreviated
 	stopped_sha1="$(git rev-parse $(cat ".git/rebase-merge/stopped-sha"))" &&
 	test "$(git rev-parse REBASE_HEAD)" = "$stopped_sha1"
@@ -326,7 +326,7 @@ test_expect_success 'retain authorship' '
 	git tag twerp &&
 	git rebase -i --onto primary HEAD^ &&
 	git show HEAD >actual &&
-	grep "^Author: Twerp Snog" actual
+	test_grep "^Author: Twerp Snog" actual
 '
 
 test_expect_success 'retain authorship w/ conflicts' '
@@ -348,7 +348,7 @@ test_expect_success 'retain authorship w/ conflicts' '
 	git rebase --continue &&
 	test_cmp_rev conflict-a^0 HEAD^ &&
 	git show >out &&
-	grep AttributeMe out
+	test_grep AttributeMe out
 '
 
 test_expect_success 'squash' '
@@ -368,7 +368,7 @@ test_expect_success 'squash' '
 
 test_expect_success 'retain authorship when squashing' '
 	git show HEAD >actual &&
-	grep "^Author: Twerp Snog" actual
+	test_grep "^Author: Twerp Snog" actual
 '
 
 test_expect_success '--continue tries to commit' '
@@ -383,7 +383,7 @@ test_expect_success '--continue tries to commit' '
 	) &&
 	test_cmp_rev HEAD^ new-branch1 &&
 	git show HEAD >actual &&
-	grep chouette actual
+	test_grep chouette actual
 '
 
 test_expect_success 'verbose flag is heeded, even after --continue' '
@@ -393,7 +393,7 @@ test_expect_success 'verbose flag is heeded, even after --continue' '
 	echo resolved > file1 &&
 	git add file1 &&
 	git rebase --continue > output &&
-	grep "^ file1 | 2 +-$" output
+	test_grep "^ file1 | 2 +-$" output
 '
 
 test_expect_success 'multi-squash only fires up editor once' '
@@ -422,7 +422,7 @@ test_expect_success 'multi-fixup does not fire up editor' '
 	) &&
 	test $base = $(git rev-parse HEAD^) &&
 	git show >output &&
-	! grep NEVER output &&
+	test_grep ! NEVER output &&
 	git checkout @{-1} &&
 	git branch -D multi-fixup
 '
@@ -487,9 +487,9 @@ test_expect_success 'squash and fixup generate correct log messages' '
 	git cat-file commit HEAD | sed -e 1,/^\$/d > actual-squash-fixup &&
 	test_cmp expect-squash-fixup actual-squash-fixup &&
 	git cat-file commit HEAD@{2} >actual &&
-	grep "^# This is a combination of 3 commits\." actual &&
+	test_grep "^# This is a combination of 3 commits\." actual &&
 	git cat-file commit HEAD@{3} >actual &&
-	grep "^# This is a combination of 2 commits\." actual  &&
+	test_grep "^# This is a combination of 2 commits\." actual  &&
 	git checkout @{-1} &&
 	git branch -D squash-fixup
 '
@@ -593,7 +593,7 @@ test_expect_success '--continue tries to commit, even for "edit"' '
 	) &&
 	test edited = $(git show HEAD:file7) &&
 	git show HEAD >actual &&
-	grep chouette actual &&
+	test_grep chouette actual &&
 	test $parent = $(git rev-parse HEAD^)
 '
 
@@ -779,22 +779,22 @@ test_expect_success 'reword' '
 		FAKE_LINES="1 2 3 reword 4" FAKE_COMMIT_MESSAGE="E changed" \
 			git rebase -i A &&
 		git show HEAD >actual &&
-		grep "E changed" actual &&
+		test_grep "E changed" actual &&
 		test $(git rev-parse primary) != $(git rev-parse HEAD) &&
 		test_cmp_rev primary^ HEAD^ &&
 		FAKE_LINES="1 2 reword 3 4" FAKE_COMMIT_MESSAGE="D changed" \
 			git rebase -i A &&
 		git show HEAD^ >actual &&
-		grep "D changed" actual &&
+		test_grep "D changed" actual &&
 		FAKE_LINES="reword 1 2 3 4" FAKE_COMMIT_MESSAGE="B changed" \
 			git rebase -i A &&
 		git show HEAD~3 >actual &&
-		grep "B changed" actual &&
+		test_grep "B changed" actual &&
 		FAKE_LINES="1 r 2 pick 3 p 4" FAKE_COMMIT_MESSAGE="C changed" \
 			git rebase -i A
 	) &&
 	git show HEAD~2 >actual &&
-	grep "C changed" actual
+	test_grep "C changed" actual
 '
 
 test_expect_success 'reword fast-forwarded empty commit' '
@@ -1043,9 +1043,9 @@ test_expect_success 'rebase -i --root retain root commit author and message' '
 		FAKE_LINES="2" git rebase -i --root
 	) &&
 	git cat-file commit HEAD >output &&
-	grep -q "^author Twerp Snog" output &&
+	test_grep "^author Twerp Snog" output &&
 	git cat-file commit HEAD >actual &&
-	grep -q "^different author$" actual
+	test_grep "^different author$" actual
 '
 
 test_expect_success 'rebase -i --root temporary sentinel commit' '
@@ -1055,7 +1055,7 @@ test_expect_success 'rebase -i --root temporary sentinel commit' '
 		test_must_fail env FAKE_LINES="2" git rebase -i --root
 	) &&
 	git cat-file commit HEAD >actual &&
-	grep "^tree $EMPTY_TREE" actual &&
+	test_grep "^tree $EMPTY_TREE" actual &&
 	git rebase --abort
 '
 
@@ -1079,7 +1079,7 @@ test_expect_success 'rebase -i --root reword original root commit' '
 			git rebase -i --root
 	) &&
 	git show HEAD^ >actual &&
-	grep "A changed" actual &&
+	test_grep "A changed" actual &&
 	test -z "$(git show -s --format=%p HEAD^)"
 '
 
@@ -1092,7 +1092,7 @@ test_expect_success 'rebase -i --root reword new root commit' '
 		git rebase -i --root
 	) &&
 	git show HEAD^ >actual &&
-	grep "C changed" actual &&
+	test_grep "C changed" actual &&
 	test -z "$(git show -s --format=%p HEAD^)"
 '
 
@@ -1315,11 +1315,11 @@ test_expect_success 'short commit ID collide' '
 		FAKE_COMMIT_MESSAGE="collide2 $(test_oid t3404_collider)" \
 		FAKE_LINES="reword 1 break 2" git rebase -i HEAD~2 &&
 		test $colliding_id = "$(git rev-parse HEAD | cut -c 1-4)" &&
-		grep "^pick $colliding_id " \
+		test_grep "^pick $colliding_id " \
 			.git/rebase-merge/git-rebase-todo.tmp &&
-		grep -E "^pick [0-9a-f]{$hexsz}" \
+		test_grep -E "^pick [0-9a-f]{$hexsz}" \
 			.git/rebase-merge/git-rebase-todo &&
-		grep -E "^pick [0-9a-f]{$hexsz}" \
+		test_grep -E "^pick [0-9a-f]{$hexsz}" \
 			.git/rebase-merge/git-rebase-todo.backup &&
 		git rebase --continue
 	) &&
@@ -1371,7 +1371,7 @@ test_expect_success 'rebase -i commits that overwrite untracked files (pick)' '
 	echo changed >file1 &&
 	git add file1 &&
 	test_must_fail git rebase --continue 2>err &&
-	grep "error: you have staged changes in your working tree" err &&
+	test_grep "error: you have staged changes in your working tree" err &&
 	git reset --hard HEAD &&
 	git rebase --continue &&
 	test_cmp_rev HEAD D &&
@@ -1398,7 +1398,7 @@ test_expect_success 'rebase -i commits that overwrite untracked files (squash)'
 	echo changed >file1 &&
 	git add file1 &&
 	test_must_fail git rebase --continue 2>err &&
-	grep "error: you have staged changes in your working tree" err &&
+	test_grep "error: you have staged changes in your working tree" err &&
 	git reset --hard HEAD &&
 	git rebase --continue &&
 	test $(git cat-file commit HEAD | sed -ne \$p) = I &&
@@ -1423,7 +1423,7 @@ test_expect_success 'rebase -i commits that overwrite untracked files (no ff)' '
 	echo changed >file1 &&
 	git add file1 &&
 	test_must_fail git rebase --continue 2>err &&
-	grep "error: you have staged changes in your working tree" err &&
+	test_grep "error: you have staged changes in your working tree" err &&
 	git reset --hard HEAD &&
 	git rebase --continue &&
 	test $(git cat-file commit HEAD | sed -ne \$p) = I
@@ -1709,15 +1709,15 @@ test_expect_success 'the first command cannot be a fixup' '
 		set_replace_editor orig &&
 		test_must_fail git rebase -i A 2>actual
 	) &&
-	grep "cannot .fixup. without a previous commit" actual &&
-	grep "You can fix this with .git rebase --edit-todo.." actual &&
+	test_grep "cannot .fixup. without a previous commit" actual &&
+	test_grep "You can fix this with .git rebase --edit-todo.." actual &&
 	# verify that the todo list has not been truncated
 	grep -v "^#" .git/rebase-merge/git-rebase-todo >actual &&
 	test_cmp orig actual &&
 
 	test_must_fail git rebase --edit-todo 2>actual &&
-	grep "cannot .fixup. without a previous commit" actual &&
-	grep "You can fix this with .git rebase --edit-todo.." actual &&
+	test_grep "cannot .fixup. without a previous commit" actual &&
+	test_grep "You can fix this with .git rebase --edit-todo.." actual &&
 	# verify that the todo list has not been truncated
 	grep -v "^#" .git/rebase-merge/git-rebase-todo >actual &&
 	test_cmp orig actual
@@ -2252,7 +2252,7 @@ test_expect_success '--update-refs: check failed ref update' '
 	git update-ref refs/heads/second third &&
 
 	test_must_fail git rebase --continue 2>err &&
-	grep "update_ref failed for ref '\''refs/heads/second'\''" err &&
+	test_grep "update_ref failed for ref '\''refs/heads/second'\''" err &&
 
 	q_to_tab >expect <<-\EOF &&
 	Updated the following refs with --update-refs:
@@ -2283,10 +2283,10 @@ test_expect_success 'bad labels and refs rejected when parsing todo list' '
 		set_replace_editor todo &&
 		test_must_fail git rebase -i HEAD 2>err
 	) &&
-	grep "'\''#'\'' is not a valid label" err &&
-	grep "'\'':invalid'\'' is not a valid label" err &&
-	grep "'\'':bad'\'' is not a valid refname" err &&
-	grep "update-ref requires a fully qualified refname e.g. refs/heads/topic" \
+	test_grep "'\''#'\'' is not a valid label" err &&
+	test_grep "'\'':invalid'\'' is not a valid label" err &&
+	test_grep "'\'':bad'\'' is not a valid refname" err &&
+	test_grep "update-ref requires a fully qualified refname e.g. refs/heads/topic" \
 		err &&
 	test_path_is_missing execed
 '
diff --git a/t/t3406-rebase-message.sh b/t/t3406-rebase-message.sh
index bc51a9d3a7..7b61188e1f 100755
--- a/t/t3406-rebase-message.sh
+++ b/t/t3406-rebase-message.sh
@@ -62,21 +62,21 @@ test_expect_success 'rebase fast-forward to main' '
 test_expect_success 'rebase --stat' '
 	git reset --hard start &&
 	git rebase --stat main >diffstat.txt &&
-	grep "^ fileX |  *1 +$" diffstat.txt
+	test_grep "^ fileX |  *1 +$" diffstat.txt
 '
 
 test_expect_success 'rebase w/config rebase.stat' '
 	git reset --hard start &&
 	git config rebase.stat true &&
 	git rebase main >diffstat.txt &&
-	grep "^ fileX |  *1 +$" diffstat.txt
+	test_grep "^ fileX |  *1 +$" diffstat.txt
 '
 
 test_expect_success 'rebase -n overrides config rebase.stat config' '
 	git reset --hard start &&
 	git config rebase.stat true &&
 	git rebase -n main >diffstat.txt &&
-	! grep "^ fileX |  *1 +$" diffstat.txt
+	test_grep ! "^ fileX |  *1 +$" diffstat.txt
 '
 
 test_expect_success 'rebase --onto outputs the invalid ref' '
diff --git a/t/t3415-rebase-autosquash.sh b/t/t3415-rebase-autosquash.sh
index 5033411a43..07a5a11678 100755
--- a/t/t3415-rebase-autosquash.sh
+++ b/t/t3415-rebase-autosquash.sh
@@ -223,7 +223,7 @@ test_expect_success 'auto squash that matches a sha1' '
 	git cat-file blob HEAD^:file1 >actual &&
 	test_cmp expect actual &&
 	git cat-file commit HEAD^ >commit &&
-	! grep "squash" commit &&
+	test_grep ! "squash" commit &&
 	grep "^extra para" commit >actual &&
 	test_line_count = 1 actual
 '
@@ -245,7 +245,7 @@ test_expect_success 'auto squash that matches longer sha1' '
 	git cat-file blob HEAD^:file1 >actual &&
 	test_cmp expect actual &&
 	git cat-file commit HEAD^ >commit &&
-	! grep "squash" commit &&
+	test_grep ! "squash" commit &&
 	grep "^extra para" commit >actual &&
 	test_line_count = 1 actual
 '
@@ -377,7 +377,7 @@ test_expect_success 'autosquash with custom inst format' '
 	git cat-file blob HEAD^:file1 >actual &&
 	test_cmp expect actual &&
 	git cat-file commit HEAD^ >commit &&
-	! grep "squash" commit &&
+	test_grep ! "squash" commit &&
 	grep first commit >actual &&
 	test_line_count = 3 actual
 '
@@ -424,7 +424,7 @@ test_expect_success 'autosquash with multiple empty patches' '
 		set_backup_editor &&
 		GIT_USE_REBASE_HELPER=false \
 		git rebase -i --force-rebase --autosquash HEAD~4 &&
-		grep empty2 .git/backup-git-rebase-todo
+		test_grep empty2 .git/backup-git-rebase-todo
 	)
 '
 
@@ -467,7 +467,7 @@ test_expect_success 'abort last squash' '
 	git commit --allow-empty --amend -m edited-first &&
 	git rebase --skip &&
 	git show >actual &&
-	! grep first actual
+	test_grep ! first actual
 '
 
 test_expect_success 'fixup a fixup' '
diff --git a/t/t3416-rebase-onto-threedots.sh b/t/t3416-rebase-onto-threedots.sh
index ea501f2b42..e7f725b8d0 100755
--- a/t/t3416-rebase-onto-threedots.sh
+++ b/t/t3416-rebase-onto-threedots.sh
@@ -107,7 +107,7 @@ test_expect_success 'rebase --onto main...side requires a single merge-base' '
 	git reset --hard K &&
 
 	test_must_fail git rebase -i --onto main...side J 2>err &&
-	grep "need exactly one merge base" err
+	test_grep "need exactly one merge base" err
 '
 
 test_expect_success 'rebase --keep-base --onto incompatible' '
@@ -196,7 +196,7 @@ test_expect_success 'rebase --keep-base requires a single merge base' '
 	git reset --hard K &&
 
 	test_must_fail git rebase -i --keep-base main 2>err &&
-	grep "need exactly one merge base with branch" err
+	test_grep "need exactly one merge base with branch" err
 '
 
 test_expect_success 'rebase --keep-base keeps cherry picks' '
diff --git a/t/t3418-rebase-continue.sh b/t/t3418-rebase-continue.sh
index f9b8999db5..03e0714864 100755
--- a/t/t3418-rebase-continue.sh
+++ b/t/t3418-rebase-continue.sh
@@ -289,18 +289,18 @@ test_expect_success 'patch file is removed before break command' '
 test_expect_success '--reschedule-failed-exec' '
 	test_when_finished "git rebase --abort" &&
 	test_must_fail git rebase -x false --reschedule-failed-exec HEAD^ &&
-	grep "^exec false" .git/rebase-merge/git-rebase-todo &&
+	test_grep "^exec false" .git/rebase-merge/git-rebase-todo &&
 	git rebase --abort &&
 	test_must_fail git -c rebase.rescheduleFailedExec=true \
 		rebase -x false HEAD^ 2>err &&
-	grep "^exec false" .git/rebase-merge/git-rebase-todo &&
+	test_grep "^exec false" .git/rebase-merge/git-rebase-todo &&
 	test_grep "has been rescheduled" err
 '
 
 test_expect_success 'rebase.rescheduleFailedExec only affects `rebase -i`' '
 	test_config rebase.rescheduleFailedExec true &&
 	test_must_fail git rebase -x false HEAD^ &&
-	grep "^exec false" .git/rebase-merge/git-rebase-todo &&
+	test_grep "^exec false" .git/rebase-merge/git-rebase-todo &&
 	git rebase --abort &&
 	git rebase HEAD^
 '
@@ -310,7 +310,7 @@ test_expect_success 'rebase.rescheduleFailedExec=true & --no-reschedule-failed-e
 	test_config rebase.rescheduleFailedExec true &&
 	test_must_fail git rebase -x false --no-reschedule-failed-exec HEAD~2 &&
 	test_must_fail git rebase --continue 2>err &&
-	! grep "has been rescheduled" err
+	test_grep ! "has been rescheduled" err
 '
 
 test_expect_success 'new rebase.rescheduleFailedExec=true setting in an ongoing rebase is ignored' '
@@ -318,7 +318,7 @@ test_expect_success 'new rebase.rescheduleFailedExec=true setting in an ongoing
 	test_must_fail git rebase -x false HEAD~2 &&
 	test_config rebase.rescheduleFailedExec true &&
 	test_must_fail git rebase --continue 2>err &&
-	! grep "has been rescheduled" err
+	test_grep ! "has been rescheduled" err
 '
 
 test_expect_success 'there is no --no-reschedule-failed-exec in an ongoing rebase' '
diff --git a/t/t3420-rebase-autostash.sh b/t/t3420-rebase-autostash.sh
index f0bbc476ff..c78052690e 100755
--- a/t/t3420-rebase-autostash.sh
+++ b/t/t3420-rebase-autostash.sh
@@ -141,8 +141,8 @@ testrebase () {
 		git checkout -b rebased-feature-branch feature-branch &&
 		echo dirty >>file3 &&
 		git rebase$type unrelated-onto-branch >actual 2>&1 &&
-		grep unrelated file4 &&
-		grep dirty file3 &&
+		test_grep unrelated file4 &&
+		test_grep dirty file3 &&
 		git checkout feature-branch
 	'
 
@@ -165,8 +165,8 @@ testrebase () {
 		echo dirty >>file3 &&
 		git add file3 &&
 		git rebase$type unrelated-onto-branch &&
-		grep unrelated file4 &&
-		grep dirty file3 &&
+		test_grep unrelated file4 &&
+		test_grep dirty file3 &&
 		git checkout feature-branch
 	'
 
@@ -197,7 +197,7 @@ testrebase () {
 		git add file2 &&
 		git rebase --continue &&
 		test_path_is_missing $dotest/autostash &&
-		grep dirty file3 &&
+		test_grep dirty file3 &&
 		git checkout feature-branch
 	'
 
@@ -212,7 +212,7 @@ testrebase () {
 		test_path_is_missing file3 &&
 		git rebase --skip &&
 		test_path_is_missing $dotest/autostash &&
-		grep dirty file3 &&
+		test_grep dirty file3 &&
 		git checkout feature-branch
 	'
 
@@ -227,7 +227,7 @@ testrebase () {
 		test_path_is_missing file3 &&
 		git rebase --abort &&
 		test_path_is_missing $dotest/autostash &&
-		grep dirty file3 &&
+		test_grep dirty file3 &&
 		git checkout feature-branch
 	'
 
@@ -244,7 +244,6 @@ testrebase () {
 		git rebase --quit &&
 		test_when_finished git stash drop &&
 		test_path_is_missing $dotest/autostash &&
-		! grep dirty file3 &&
 		git stash show -p >actual &&
 		test_cmp expect actual &&
 		git reset --hard &&
@@ -260,11 +259,11 @@ testrebase () {
 		git rebase$type unrelated-onto-branch >actual 2>&1 &&
 		test_path_is_missing $dotest &&
 		git reset --hard &&
-		grep unrelated file4 &&
-		! grep dirty file4 &&
+		test_grep unrelated file4 &&
+		test_grep ! dirty file4 &&
 		git checkout feature-branch &&
 		git stash pop &&
-		grep dirty file4
+		test_grep dirty file4
 	'
 
 	test_expect_success "rebase$type: check output with conflicting stash" '
@@ -286,7 +285,7 @@ test_expect_success "rebase: fast-forward rebase" '
 	test_when_finished git branch -D behind-feature-branch &&
 	echo dirty >>file1 &&
 	git rebase feature-branch &&
-	grep dirty file1 &&
+	test_grep dirty file1 &&
 	git checkout feature-branch
 '
 
@@ -297,7 +296,7 @@ test_expect_success "rebase: noop rebase" '
 	test_when_finished git branch -D same-feature-branch &&
 	echo dirty >>file1 &&
 	git rebase feature-branch &&
-	grep dirty file1 &&
+	test_grep dirty file1 &&
 	git checkout feature-branch
 '
 
diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
index b9408f9ba1..d6830b82e0 100755
--- a/t/t3422-rebase-incompatible-options.sh
+++ b/t/t3422-rebase-incompatible-options.sh
@@ -102,13 +102,13 @@ test_rebase_am_only () {
 	test_expect_success "$opt incompatible with rebase.rebaseMerges" "
 		git checkout B^0 &&
 		test_must_fail git -c rebase.rebaseMerges=true rebase $opt A 2>err &&
-		grep -e --no-rebase-merges err
+		test_grep -e --no-rebase-merges err
 	"
 
 	test_expect_success "$opt incompatible with rebase.updateRefs" "
 		git checkout B^0 &&
 		test_must_fail git -c rebase.updateRefs=true rebase $opt A 2>err &&
-		grep -e --no-update-refs err
+		test_grep -e --no-update-refs err
 	"
 
 	test_expect_success "$opt okay with overridden rebase.rebaseMerges" "
diff --git a/t/t3429-rebase-edit-todo.sh b/t/t3429-rebase-edit-todo.sh
index abd66f3602..28e4bdd0d9 100755
--- a/t/t3429-rebase-edit-todo.sh
+++ b/t/t3429-rebase-edit-todo.sh
@@ -19,7 +19,7 @@ test_expect_success 'rebase exec modifies rebase-todo' '
 
 test_expect_success 'rebase exec with an empty list does not exec anything' '
 	git rebase HEAD -x "true" 2>output &&
-	! grep "Executing: true" output
+	test_grep ! "Executing: true" output
 '
 
 test_expect_success 'loose object cache vs re-reading todo list' '
diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index 84b2d0e664..9bd61c58b3 100755
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -161,7 +161,7 @@ test_expect_success '`reset` rejects trees' '
 	test_when_finished "test_might_fail git rebase --abort" &&
 	test_must_fail env GIT_SEQUENCE_EDITOR="echo reset A^{tree} >" \
 		git rebase -i B C >out 2>err &&
-	grep "object .* is a tree" err &&
+	test_grep "object .* is a tree" err &&
 	test_must_be_empty out
 '
 
@@ -170,7 +170,7 @@ test_expect_success '`reset` only looks for labels under refs/rewritten/' '
 	git branch refs/rewritten/my-label A &&
 	test_must_fail env GIT_SEQUENCE_EDITOR="echo reset my-label >" \
 		git rebase -i B C >out 2>err &&
-	grep "could not resolve ${SQ}my-label${SQ}" err &&
+	test_grep "could not resolve ${SQ}my-label${SQ}" err &&
 	test_must_be_empty out
 '
 
@@ -185,18 +185,18 @@ test_expect_success 'failed `merge -C` writes patch (may be rescheduled, too)' '
 	test_tick &&
 	test_must_fail git rebase -ir HEAD &&
 	test_cmp_rev REBASE_HEAD H^0 &&
-	grep "^merge -C .* G$" .git/rebase-merge/done &&
-	grep "^merge -C .* G$" .git/rebase-merge/git-rebase-todo &&
+	test_grep "^merge -C .* G$" .git/rebase-merge/done &&
+	test_grep "^merge -C .* G$" .git/rebase-merge/git-rebase-todo &&
 	test_path_is_missing .git/rebase-merge/patch &&
 	echo changed >file1 &&
 	git add file1 &&
 	test_must_fail git rebase --continue 2>err &&
-	grep "error: you have staged changes in your working tree" err &&
+	test_grep "error: you have staged changes in your working tree" err &&
 
 	: fail because of merge conflict &&
 	git reset --hard conflicting-G &&
 	test_must_fail git rebase --continue &&
-	! grep "^merge -C .* G$" .git/rebase-merge/git-rebase-todo &&
+	test_grep ! "^merge -C .* G$" .git/rebase-merge/git-rebase-todo &&
 	test_path_is_file .git/rebase-merge/patch
 '
 
@@ -208,8 +208,8 @@ test_expect_success 'failed `merge <branch>` does not crash' '
 	test_config sequence.editor \""$PWD"/replace-editor.sh\" &&
 	test_tick &&
 	test_must_fail git rebase -ir HEAD &&
-	! grep "^merge G$" .git/rebase-merge/git-rebase-todo &&
-	grep "^Merge branch ${SQ}G${SQ}$" .git/rebase-merge/message
+	test_grep ! "^merge G$" .git/rebase-merge/git-rebase-todo &&
+	test_grep "^Merge branch ${SQ}G${SQ}$" .git/rebase-merge/message
 '
 
 test_expect_success 'merge -c commits before rewording and reloads todo-list' '
@@ -481,8 +481,8 @@ test_expect_success 'labels that are object IDs are rewritten' '
 	test_config sequence.editor \""$PWD"/replace-editor.sh\" &&
 	test_tick &&
 	git rebase -i -r A &&
-	grep "^label $third-" .git/ORIGINAL-TODO &&
-	! grep "^label $third$" .git/ORIGINAL-TODO
+	test_grep "^label $third-" .git/ORIGINAL-TODO &&
+	test_grep ! "^label $third$" .git/ORIGINAL-TODO
 '
 
 test_expect_success 'octopus merges' '
@@ -533,9 +533,9 @@ test_expect_success 'with --autosquash and --exec' '
 	EOF
 	test_tick &&
 	git rebase -ir --autosquash --exec ./show.sh A >actual &&
-	grep "B: +Booh" actual &&
-	grep "E: +Booh" actual &&
-	grep "G: +G" actual
+	test_grep "B: +Booh" actual &&
+	test_grep "E: +Booh" actual &&
+	test_grep "G: +G" actual
 '
 
 test_expect_success '--continue after resolving conflicts after a merge' '
@@ -546,7 +546,7 @@ test_expect_success '--continue after resolving conflicts after a merge' '
 	git checkout -b conflicts-in-merge H &&
 	test_commit H2 H2.t conflicts H2-conflict &&
 	test_must_fail git rebase -r already-has-g &&
-	grep conflicts H2.t &&
+	test_grep conflicts H2.t &&
 	echo resolved >H2.t &&
 	git add -u &&
 	git rebase --continue &&
@@ -616,9 +616,9 @@ test_expect_success 'truncate label names' '
 
 	done="$(git rev-parse --git-path rebase-merge/done)" &&
 	git -c rebase.maxLabelLength=14 rebase --rebase-merges -x "cp \"$done\" out" --root &&
-	grep "label 0123456789-我$" out &&
+	test_grep "label 0123456789-我$" out &&
 	git -c rebase.maxLabelLength=13 rebase --rebase-merges -x "cp \"$done\" out" --root &&
-	grep "label 0123456789-$" out
+	test_grep "label 0123456789-$" out
 '
 
 test_expect_success 'reword fast-forwarded empty merge commit' '
diff --git a/t/t3500-cherry.sh b/t/t3500-cherry.sh
index 3e66827d76..03655c8a48 100755
--- a/t/t3500-cherry.sh
+++ b/t/t3500-cherry.sh
@@ -100,8 +100,8 @@ test_expect_success 'cherry in partial clone does bulk prefetch' '
 		GIT_TRACE2_EVENT="$(pwd)/trace2.output" git cherry upstream-with-space feature-without-space >actual &&
 		test_cmp ../expect actual &&
 
-		! grep "child_start.*fetch.negotiationAlgorithm" trace2.output &&
-		! grep "\"key\":\"fetch_count\"" trace2.output
+		test_grep ! "child_start.*fetch.negotiationAlgorithm" trace2.output &&
+		test_grep ! "\"key\":\"fetch_count\"" trace2.output
 	)
 '
 
diff --git a/t/t3501-revert-cherry-pick.sh b/t/t3501-revert-cherry-pick.sh
index 8025a28cfd..7291a8fae1 100755
--- a/t/t3501-revert-cherry-pick.sh
+++ b/t/t3501-revert-cherry-pick.sh
@@ -67,7 +67,7 @@ test_expect_success 'cherry-pick after renaming branch' '
 	git checkout rename2 &&
 	git cherry-pick added &&
 	test_cmp_rev rename2 HEAD^ &&
-	grep "Add extra line at the end" opos &&
+	test_grep "Add extra line at the end" opos &&
 	git reflog -1 | grep cherry-pick
 
 '
@@ -162,7 +162,7 @@ test_expect_success 'cherry-pick works with dirty renamed file' '
 	echo modified >renamed &&
 	git cherry-pick refs/heads/unrelated &&
 	test $(git rev-parse :0:renamed) = $(git rev-parse HEAD~2:to-rename.t) &&
-	grep -q "^modified$" renamed
+	test_grep "^modified$" renamed
 '
 
 test_expect_success 'advice from failed revert' '
@@ -253,7 +253,7 @@ test_expect_success 'identification of reverted commit (revert.reference)' '
 test_expect_success 'cherry-pick is unaware of --reference (for now)' '
 	test_when_finished "git reset --hard" &&
 	test_must_fail git cherry-pick --reference HEAD 2>actual &&
-	grep "^usage: git cherry-pick" actual
+	test_grep "^usage: git cherry-pick" actual
 '
 
 test_done
diff --git a/t/t3504-cherry-pick-rerere.sh b/t/t3504-cherry-pick-rerere.sh
index 18aeba161c..462973fa91 100755
--- a/t/t3504-cherry-pick-rerere.sh
+++ b/t/t3504-cherry-pick-rerere.sh
@@ -98,9 +98,9 @@ test_expect_success 'cherry-pick --rerere-autoupdate more than once' '
 test_expect_success 'cherry-pick conflict without rerere' '
 	test_config rerere.enabled false &&
 	test_must_fail git cherry-pick foo-main &&
-	grep ===== foo &&
-	grep foo-dev foo &&
-	grep foo-main foo
+	test_grep ===== foo &&
+	test_grep foo-dev foo &&
+	test_grep foo-main foo
 '
 
 test_done
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 66ff9db270..5777dff496 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -580,10 +580,10 @@ test_expect_success '--continue respects opts' '
 	git cat-file commit HEAD~1 >picked_msg &&
 	git cat-file commit HEAD~2 >unrelatedpick_msg &&
 	git cat-file commit HEAD~3 >initial_msg &&
-	! grep "cherry picked from" initial_msg &&
-	grep "cherry picked from" unrelatedpick_msg &&
-	grep "cherry picked from" picked_msg &&
-	grep "cherry picked from" anotherpick_msg
+	test_grep ! "cherry picked from" initial_msg &&
+	test_grep "cherry picked from" unrelatedpick_msg &&
+	test_grep "cherry picked from" picked_msg &&
+	test_grep "cherry picked from" anotherpick_msg
 '
 
 test_expect_success '--continue of single-pick respects -x' '
@@ -594,7 +594,7 @@ test_expect_success '--continue of single-pick respects -x' '
 	git cherry-pick --continue &&
 	test_path_is_missing .git/sequencer &&
 	git cat-file commit HEAD >msg &&
-	grep "cherry picked from" msg
+	test_grep "cherry picked from" msg
 '
 
 test_expect_success '--continue respects -x in first commit in multi-pick' '
@@ -606,7 +606,7 @@ test_expect_success '--continue respects -x in first commit in multi-pick' '
 	test_path_is_missing .git/sequencer &&
 	git cat-file commit HEAD^ >msg &&
 	picked=$(git rev-parse --verify picked) &&
-	grep "cherry picked from.*$picked" msg
+	test_grep "cherry picked from.*$picked" msg
 '
 
 test_expect_failure '--signoff is automatically propagated to resolved conflict' '
@@ -621,10 +621,10 @@ test_expect_failure '--signoff is automatically propagated to resolved conflict'
 	git cat-file commit HEAD~1 >picked_msg &&
 	git cat-file commit HEAD~2 >unrelatedpick_msg &&
 	git cat-file commit HEAD~3 >initial_msg &&
-	! grep "Signed-off-by:" initial_msg &&
-	grep "Signed-off-by:" unrelatedpick_msg &&
-	! grep "Signed-off-by:" picked_msg &&
-	grep "Signed-off-by:" anotherpick_msg
+	test_grep ! "Signed-off-by:" initial_msg &&
+	test_grep "Signed-off-by:" unrelatedpick_msg &&
+	test_grep ! "Signed-off-by:" picked_msg &&
+	test_grep "Signed-off-by:" anotherpick_msg
 '
 
 test_expect_failure '--signoff dropped for implicit commit of resolution, multi-pick case' '
@@ -637,7 +637,7 @@ test_expect_failure '--signoff dropped for implicit commit of resolution, multi-
 	git diff --exit-code HEAD &&
 	test_cmp_rev initial HEAD^^ &&
 	git cat-file commit HEAD^ >msg &&
-	! grep Signed-off-by: msg
+	test_grep ! Signed-off-by: msg
 '
 
 test_expect_failure 'sign-off needs to be reaffirmed after conflict resolution, single-pick case' '
@@ -650,7 +650,7 @@ test_expect_failure 'sign-off needs to be reaffirmed after conflict resolution,
 	git diff --exit-code HEAD &&
 	test_cmp_rev initial HEAD^ &&
 	git cat-file commit HEAD >msg &&
-	! grep Signed-off-by: msg
+	test_grep ! Signed-off-by: msg
 '
 
 test_expect_success 'malformed instruction sheet 1' '
diff --git a/t/t3602-rm-sparse-checkout.sh b/t/t3602-rm-sparse-checkout.sh
index 02c7acd617..252df28bbf 100755
--- a/t/t3602-rm-sparse-checkout.sh
+++ b/t/t3602-rm-sparse-checkout.sh
@@ -79,8 +79,8 @@ test_expect_success 'do not advice about sparse entries when they do not match t
 	git reset --hard &&
 	git sparse-checkout set a &&
 	test_must_fail git rm nonexistent 2>stderr &&
-	grep "fatal: pathspec .nonexistent. did not match any files" stderr &&
-	! grep -F -f sparse_error_header stderr
+	test_grep "fatal: pathspec .nonexistent. did not match any files" stderr &&
+	test_grep ! -F -f sparse_error_header stderr
 '
 
 test_expect_success 'do not warn about sparse entries when pathspec matches dense entries' '
diff --git a/t/t3705-add-sparse-checkout.sh b/t/t3705-add-sparse-checkout.sh
index 53a4782267..64ad7a2949 100755
--- a/t/t3705-add-sparse-checkout.sh
+++ b/t/t3705-add-sparse-checkout.sh
@@ -149,8 +149,8 @@ test_expect_success 'git add --dry-run --ignore-missing warn on sparse path' '
 test_expect_success 'do not advice about sparse entries when they do not match the pathspec' '
 	setup_sparse_entry &&
 	test_must_fail git add nonexistent 2>stderr &&
-	grep "fatal: pathspec .nonexistent. did not match any files" stderr &&
-	! grep -F -f sparse_error_header stderr
+	test_grep "fatal: pathspec .nonexistent. did not match any files" stderr &&
+	test_grep ! -F -f sparse_error_header stderr
 '
 
 test_expect_success 'do not warn when pathspec matches dense entries' '
@@ -184,19 +184,19 @@ test_expect_success 'git add fails outside of sparse-checkout definition' '
 	git -c core.autocrlf=input add --sparse sparse_entry 2>stderr &&
 	test_must_be_empty stderr &&
 	git ls-files --stage >actual &&
-	grep "^100644 .*sparse_entry\$" actual &&
+	test_grep "^100644 .*sparse_entry\$" actual &&
 
 	git add --sparse --chmod=+x sparse_entry 2>stderr &&
 	test_must_be_empty stderr &&
 	git ls-files --stage >actual &&
-	grep "^100755 .*sparse_entry\$" actual &&
+	test_grep "^100755 .*sparse_entry\$" actual &&
 
 	git reset &&
 
 	# This will print a message over stderr on Windows.
 	git add --sparse --renormalize sparse_entry &&
 	git status --porcelain >actual &&
-	grep "^M  sparse_entry\$" actual
+	test_grep "^M  sparse_entry\$" actual
 '
 
 test_expect_success 'add obeys advice.updateSparsePath' '
diff --git a/t/t3800-mktag.sh b/t/t3800-mktag.sh
index e3cf0ffbe5..d3ddf076c4 100755
--- a/t/t3800-mktag.sh
+++ b/t/t3800-mktag.sh
@@ -535,9 +535,9 @@ test_expect_success 'invalid header entry config & fsck' '
 
 	git fsck &&
 	git -c fsck.extraHeaderEntry=warn fsck 2>err &&
-	grep "warning .*extraHeaderEntry:" err &&
+	test_grep "warning .*extraHeaderEntry:" err &&
 	test_must_fail git -c fsck.extraHeaderEntry=error 2>err fsck &&
-	grep "error .* extraHeaderEntry:" err
+	test_grep "error .* extraHeaderEntry:" err
 '
 
 cat >tag.sig <<EOF
diff --git a/t/t3901-i18n-patch.sh b/t/t3901-i18n-patch.sh
index ef7d7e1edc..0f32d98a2d 100755
--- a/t/t3901-i18n-patch.sh
+++ b/t/t3901-i18n-patch.sh
@@ -26,9 +26,9 @@ check_encoding () {
 		git cat-file commit HEAD~$j |
 		case "$header" in
 		8859)
-			grep "^encoding ISO8859-1" ;;
+			grep "^encoding ISO8859-1" ;; # lint-ok: piped stdin via case
 		*)
-			ret=0; grep "^encoding ISO8859-1" || ret=$?
+			ret=0; grep "^encoding ISO8859-1" || ret=$? # lint-ok: piped stdin via case
 			test "$ret" != 0 ;;
 		esac || return 1
 		j=$i
@@ -81,10 +81,10 @@ test_expect_success 'format-patch output (ISO-8859-1)' '
 
 	git format-patch --stdout main..HEAD^ >out-l1 &&
 	git format-patch --stdout HEAD^ >out-l2 &&
-	grep "^Content-Type: text/plain; charset=ISO8859-1" out-l1 &&
-	grep "^From: =?ISO8859-1?q?=C1=E9=ED=20=F3=FA?=" out-l1 &&
-	grep "^Content-Type: text/plain; charset=ISO8859-1" out-l2 &&
-	grep "^From: =?ISO8859-1?q?=C1=E9=ED=20=F3=FA?=" out-l2
+	test_grep "^Content-Type: text/plain; charset=ISO8859-1" out-l1 &&
+	test_grep "^From: =?ISO8859-1?q?=C1=E9=ED=20=F3=FA?=" out-l1 &&
+	test_grep "^Content-Type: text/plain; charset=ISO8859-1" out-l2 &&
+	test_grep "^From: =?ISO8859-1?q?=C1=E9=ED=20=F3=FA?=" out-l2
 '
 
 test_expect_success 'format-patch output (UTF-8)' '
@@ -92,10 +92,10 @@ test_expect_success 'format-patch output (UTF-8)' '
 
 	git format-patch --stdout main..HEAD^ >out-u1 &&
 	git format-patch --stdout HEAD^ >out-u2 &&
-	grep "^Content-Type: text/plain; charset=UTF-8" out-u1 &&
-	grep "^From: =?UTF-8?q?=C3=81=C3=A9=C3=AD=20=C3=B3=C3=BA?=" out-u1 &&
-	grep "^Content-Type: text/plain; charset=UTF-8" out-u2 &&
-	grep "^From: =?UTF-8?q?=C3=81=C3=A9=C3=AD=20=C3=B3=C3=BA?=" out-u2
+	test_grep "^Content-Type: text/plain; charset=UTF-8" out-u1 &&
+	test_grep "^From: =?UTF-8?q?=C3=81=C3=A9=C3=AD=20=C3=B3=C3=BA?=" out-u1 &&
+	test_grep "^Content-Type: text/plain; charset=UTF-8" out-u2 &&
+	test_grep "^From: =?UTF-8?q?=C3=81=C3=A9=C3=AD=20=C3=B3=C3=BA?=" out-u2
 '
 
 test_expect_success 'rebase (U/U)' '
diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
index ecc35aae82..53328b8475 100755
--- a/t/t3903-stash.sh
+++ b/t/t3903-stash.sh
@@ -20,21 +20,21 @@ test_expect_success 'setup' '
 
 test_expect_success 'usage on cmd and subcommand invalid option' '
 	test_expect_code 129 git stash --invalid-option 2>usage &&
-	grep "or: git stash" usage &&
+	test_grep "or: git stash" usage &&
 
 	test_expect_code 129 git stash push --invalid-option 2>usage &&
-	! grep "or: git stash" usage
+	test_grep ! "or: git stash" usage
 '
 
 test_expect_success 'usage on main command -h emits a summary of subcommands' '
 	test_expect_code 129 git stash -h >usage &&
-	grep -F "usage: git stash list" usage &&
-	grep -F "or: git stash show" usage
+	test_grep -F "usage: git stash list" usage &&
+	test_grep -F "or: git stash show" usage
 '
 
 test_expect_success 'usage for subcommands should emit subcommand usage' '
 	test_expect_code 129 git stash push -h >usage &&
-	grep -F "usage: git stash [push" usage
+	test_grep -F "usage: git stash [push" usage
 '
 
 diff_cmp () {
@@ -965,7 +965,7 @@ test_expect_success 'store updates stash ref and reflog' '
 	test $(git rev-parse stash) = $STASH_ID &&
 	git reflog --format=%H stash| grep $STASH_ID &&
 	git stash pop &&
-	grep quux bazzy
+	test_grep quux bazzy
 '
 
 test_expect_success 'handle stash specification with spaces' '
@@ -977,7 +977,7 @@ test_expect_success 'handle stash specification with spaces' '
 	echo cow >file &&
 	git stash &&
 	git stash apply "stash@{$stamp}" &&
-	grep pig file
+	test_grep pig file
 '
 
 test_expect_success 'setup stash with index and worktree changes' '
@@ -1500,9 +1500,9 @@ test_expect_success 'stash export can accept specified stashes' '
 
 test_expect_success 'stash export rejects invalid arguments' '
 	test_must_fail git stash export --print --to-ref refs/heads/invalid 2>err &&
-	grep "exactly one of --print and --to-ref is required" err &&
+	test_grep "exactly one of --print and --to-ref is required" err &&
 	test_must_fail git stash export 2>err2 &&
-	grep "exactly one of --print and --to-ref is required" err2
+	test_grep "exactly one of --print and --to-ref is required" err2
 '
 
 test_expect_success 'stash can import and export zero stashes' '
@@ -1519,7 +1519,7 @@ test_expect_success 'stash rejects invalid attempts to import commits' '
 	git stash import foo &&
 	test_must_fail git stash import HEAD 2>output &&
 	oid=$(git rev-parse HEAD) &&
-	grep "$oid is not a valid exported stash commit" output &&
+	test_grep "$oid is not a valid exported stash commit" output &&
 	test_cmp_rev stash@{0} t-stash0 &&
 
 	git checkout --orphan orphan &&
@@ -1527,7 +1527,7 @@ test_expect_success 'stash rejects invalid attempts to import commits' '
 	git update-ref refs/heads/orphan "$(cat fake-commit)" &&
 	oid=$(git rev-parse HEAD) &&
 	test_must_fail git stash import orphan 2>output &&
-	grep "found stash commit $oid without expected prefix" output &&
+	test_grep "found stash commit $oid without expected prefix" output &&
 	test_cmp_rev stash@{0} t-stash0 &&
 
 	git checkout --orphan orphan2 &&
@@ -1535,7 +1535,7 @@ test_expect_success 'stash rejects invalid attempts to import commits' '
 	git update-ref refs/heads/orphan2 "$(cat fake-commit)" &&
 	oid=$(git rev-parse HEAD) &&
 	test_must_fail git stash import orphan2 2>output &&
-	grep "found root commit $oid with invalid data" output &&
+	test_grep "found root commit $oid with invalid data" output &&
 	test_cmp_rev stash@{0} t-stash0
 '
 
@@ -1741,7 +1741,7 @@ test_expect_success 'submodules does not affect the branch recorded in stash mes
 		git stash push -m "custom stash for work_branch" &&
 
 		git stash list >../actual_stash_list.txt &&
-		grep "On work_branch: custom stash for work_branch" ../actual_stash_list.txt
+		test_grep "On work_branch: custom stash for work_branch" ../actual_stash_list.txt
 	)
 '
 
@@ -1751,7 +1751,7 @@ test_expect_success SANITIZE_LEAK 'stash show handles -- without leaking' '
 
 test_expect_success 'controlled error return on unrecognized option' '
 	test_expect_code 129 git stash show -p --invalid 2>usage &&
-	grep -e "^usage: git stash show" usage
+	test_grep -e "^usage: git stash show" usage
 '
 
 test_expect_success 'stash.index=true implies --index' '
diff --git a/t/t3904-stash-patch.sh b/t/t3904-stash-patch.sh
index 90a4ff2c10..adc45c7073 100755
--- a/t/t3904-stash-patch.sh
+++ b/t/t3904-stash-patch.sh
@@ -103,8 +103,8 @@ test_expect_success 'stash -p with split hunk' '
 	printf "%s\n" s n y q |
 	git stash -p 2>error &&
 	test_must_be_empty error &&
-	grep "added line 1" test &&
-	! grep "added line 2" test
+	test_grep "added line 1" test &&
+	test_grep ! "added line 2" test
 '
 
 test_expect_success 'stash -p not confused by GIT_PAGER_IN_USE' '
diff --git a/t/t3908-stash-in-worktree.sh b/t/t3908-stash-in-worktree.sh
index 2b2b366ef9..e7ae838bb2 100755
--- a/t/t3908-stash-in-worktree.sh
+++ b/t/t3908-stash-in-worktree.sh
@@ -21,7 +21,7 @@ test_expect_success 'apply in subdirectory' '
 		git stash &&
 		git stash apply >out
 	) &&
-	grep "\.\.\/initial\.t" wt/subdir/out
+	test_grep "\.\.\/initial\.t" wt/subdir/out
 '
 
 test_done
diff --git a/t/t4000-diff-format.sh b/t/t4000-diff-format.sh
index 32b14e3a71..bc46c2a2a9 100755
--- a/t/t4000-diff-format.sh
+++ b/t/t4000-diff-format.sh
@@ -84,7 +84,7 @@ test_expect_success 'git diff-files --no-patch --patch shows the patch' '
 
 test_expect_success 'git diff-files --no-patch --patch-with-raw shows the patch and raw data' '
 	git diff-files --no-patch --patch-with-raw >actual &&
-	grep -q "^:100644 100755 .* $ZERO_OID M	path0\$" actual &&
+	test_grep "^:100644 100755 .* $ZERO_OID M	path0\$" actual &&
 	tail -n +4 actual >actual-patch &&
 	compare_diff_patch expected actual-patch
 '
diff --git a/t/t4001-diff-rename.sh b/t/t4001-diff-rename.sh
index 4f520d600d..ad474100af 100755
--- a/t/t4001-diff-rename.sh
+++ b/t/t4001-diff-rename.sh
@@ -189,7 +189,7 @@ test_expect_success 'setup for many rename source candidates' '
 	M	path1
 	EOF
 	test_cmp expect actual.munged &&
-	grep warning actual.err
+	test_grep warning actual.err
 '
 
 test_expect_success 'rename pretty print with nothing in common' '
@@ -258,7 +258,7 @@ test_expect_success 'diff-tree -l0 defaults to a big rename limit, not zero' '
 
 	git diff-tree -M -l0 HEAD HEAD^ >actual &&
 	# Verify that a rename from myotherfile to myfile was detected
-	grep "myotherfile.*myfile" actual
+	test_grep "myotherfile.*myfile" actual
 '
 
 test_expect_success 'basename similarity vs best similarity' '
diff --git a/t/t4011-diff-symlink.sh b/t/t4011-diff-symlink.sh
index ac837b6c9e..4103bd6989 100755
--- a/t/t4011-diff-symlink.sh
+++ b/t/t4011-diff-symlink.sh
@@ -140,7 +140,7 @@ test_expect_success SYMLINKS 'diff symlinks with non-existing targets' '
 	ln -s narf pinky &&
 	ln -s take\ over brain &&
 	test_must_fail git diff --no-index pinky brain >output 2>output.err &&
-	grep narf output &&
+	test_grep narf output &&
 	test_must_be_empty output.err
 '
 
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index d35695f5b0..b7a382c881 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -778,7 +778,7 @@ test_expect_success 'diff.{src,dst}Prefix ignored with --default-prefix' '
 test_expect_success 'diff --no-renames cannot be abbreviated' '
 	test_expect_code 129 git diff --no-rename >actual 2>error &&
 	test_must_be_empty actual &&
-	grep "invalid option: --no-rename" error
+	test_grep "invalid option: --no-rename" error
 '
 
 test_done
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 0b89d127b5..4afcd85779 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -119,17 +119,17 @@ test_expect_success 'format-patch --ignore-if-in-upstream result applies' '
 
 test_expect_success 'commit did not screw up the log message' '
 	git cat-file commit side >actual &&
-	grep "^Side .* with .* backslash-n" actual
+	test_grep "^Side .* with .* backslash-n" actual
 '
 
 test_expect_success 'format-patch did not screw up the log message' '
-	grep "^Subject: .*Side changes #3 with .* backslash-n" patch0 &&
-	grep "^Subject: .*Side changes #3 with .* backslash-n" patch1
+	test_grep "^Subject: .*Side changes #3 with .* backslash-n" patch0 &&
+	test_grep "^Subject: .*Side changes #3 with .* backslash-n" patch1
 '
 
 test_expect_success 'replay did not screw up the log message' '
 	git cat-file commit rebuild-1 >actual &&
-	grep "^Side .* with .* backslash-n" actual
+	test_grep "^Side .* with .* backslash-n" actual
 '
 
 test_expect_success 'format-patch empty commit' '
@@ -145,8 +145,8 @@ test_expect_success 'extra headers' '
 " &&
 	git format-patch --stdout main..side >patch2 &&
 	sed -e "/^\$/q" patch2 >hdrs2 &&
-	grep "^To: R E Cipient <rcipient@example.com>\$" hdrs2 &&
-	grep "^Cc: S E Cipient <scipient@example.com>\$" hdrs2
+	test_grep "^To: R E Cipient <rcipient@example.com>\$" hdrs2 &&
+	test_grep "^Cc: S E Cipient <scipient@example.com>\$" hdrs2
 '
 
 test_expect_success 'extra headers without newlines' '
@@ -154,8 +154,8 @@ test_expect_success 'extra headers without newlines' '
 	git config --add format.headers "Cc: S E Cipient <scipient@example.com>" &&
 	git format-patch --stdout main..side >patch3 &&
 	sed -e "/^\$/q" patch3 >hdrs3 &&
-	grep "^To: R E Cipient <rcipient@example.com>\$" hdrs3 &&
-	grep "^Cc: S E Cipient <scipient@example.com>\$" hdrs3
+	test_grep "^To: R E Cipient <rcipient@example.com>\$" hdrs3 &&
+	test_grep "^Cc: S E Cipient <scipient@example.com>\$" hdrs3
 '
 
 test_expect_success 'extra headers with multiple To:s' '
@@ -163,79 +163,79 @@ test_expect_success 'extra headers with multiple To:s' '
 	git config --add format.headers "To: S E Cipient <scipient@example.com>" &&
 	git format-patch --stdout main..side >patch4 &&
 	sed -e "/^\$/q" patch4 >hdrs4 &&
-	grep "^To: R E Cipient <rcipient@example.com>,\$" hdrs4 &&
-	grep "^ *S E Cipient <scipient@example.com>\$" hdrs4
+	test_grep "^To: R E Cipient <rcipient@example.com>,\$" hdrs4 &&
+	test_grep "^ *S E Cipient <scipient@example.com>\$" hdrs4
 '
 
 test_expect_success 'additional command line cc (ascii)' '
 	git config --replace-all format.headers "Cc: R E Cipient <rcipient@example.com>" &&
 	git format-patch --cc="S E Cipient <scipient@example.com>" --stdout main..side >patch5 &&
 	sed -e "/^\$/q" patch5 >hdrs5 &&
-	grep "^Cc: R E Cipient <rcipient@example.com>,\$" hdrs5 &&
-	grep "^ *S E Cipient <scipient@example.com>\$" hdrs5
+	test_grep "^Cc: R E Cipient <rcipient@example.com>,\$" hdrs5 &&
+	test_grep "^ *S E Cipient <scipient@example.com>\$" hdrs5
 '
 
 test_expect_failure 'additional command line cc (rfc822)' '
 	git config --replace-all format.headers "Cc: R E Cipient <rcipient@example.com>" &&
 	git format-patch --cc="S. E. Cipient <scipient@example.com>" --stdout main..side >patch5 &&
 	sed -e "/^\$/q" patch5 >hdrs5 &&
-	grep "^Cc: R E Cipient <rcipient@example.com>,\$" hdrs5 &&
-	grep "^ *\"S. E. Cipient\" <scipient@example.com>\$" hdrs5
+	test_grep "^Cc: R E Cipient <rcipient@example.com>,\$" hdrs5 &&
+	test_grep "^ *\"S. E. Cipient\" <scipient@example.com>\$" hdrs5
 '
 
 test_expect_success 'command line headers' '
 	git config --unset-all format.headers &&
 	git format-patch --add-header="Cc: R E Cipient <rcipient@example.com>" --stdout main..side >patch6 &&
 	sed -e "/^\$/q" patch6 >hdrs6 &&
-	grep "^Cc: R E Cipient <rcipient@example.com>\$" hdrs6
+	test_grep "^Cc: R E Cipient <rcipient@example.com>\$" hdrs6
 '
 
 test_expect_success 'configuration headers and command line headers' '
 	git config --replace-all format.headers "Cc: R E Cipient <rcipient@example.com>" &&
 	git format-patch --add-header="Cc: S E Cipient <scipient@example.com>" --stdout main..side >patch7 &&
 	sed -e "/^\$/q" patch7 >hdrs7 &&
-	grep "^Cc: R E Cipient <rcipient@example.com>,\$" hdrs7 &&
-	grep "^ *S E Cipient <scipient@example.com>\$" hdrs7
+	test_grep "^Cc: R E Cipient <rcipient@example.com>,\$" hdrs7 &&
+	test_grep "^ *S E Cipient <scipient@example.com>\$" hdrs7
 '
 
 test_expect_success 'command line To: header (ascii)' '
 	git config --unset-all format.headers &&
 	git format-patch --to="R E Cipient <rcipient@example.com>" --stdout main..side >patch8 &&
 	sed -e "/^\$/q" patch8 >hdrs8 &&
-	grep "^To: R E Cipient <rcipient@example.com>\$" hdrs8
+	test_grep "^To: R E Cipient <rcipient@example.com>\$" hdrs8
 '
 
 test_expect_failure 'command line To: header (rfc822)' '
 	git format-patch --to="R. E. Cipient <rcipient@example.com>" --stdout main..side >patch8 &&
 	sed -e "/^\$/q" patch8 >hdrs8 &&
-	grep "^To: \"R. E. Cipient\" <rcipient@example.com>\$" hdrs8
+	test_grep "^To: \"R. E. Cipient\" <rcipient@example.com>\$" hdrs8
 '
 
 test_expect_failure 'command line To: header (rfc2047)' '
 	git format-patch --to="R Ä Cipient <rcipient@example.com>" --stdout main..side >patch8 &&
 	sed -e "/^\$/q" patch8 >hdrs8 &&
-	grep "^To: =?UTF-8?q?R=20=C3=84=20Cipient?= <rcipient@example.com>\$" hdrs8
+	test_grep "^To: =?UTF-8?q?R=20=C3=84=20Cipient?= <rcipient@example.com>\$" hdrs8
 '
 
 test_expect_success 'configuration To: header (ascii)' '
 	git config format.to "R E Cipient <rcipient@example.com>" &&
 	git format-patch --stdout main..side >patch9 &&
 	sed -e "/^\$/q" patch9 >hdrs9 &&
-	grep "^To: R E Cipient <rcipient@example.com>\$" hdrs9
+	test_grep "^To: R E Cipient <rcipient@example.com>\$" hdrs9
 '
 
 test_expect_failure 'configuration To: header (rfc822)' '
 	git config format.to "R. E. Cipient <rcipient@example.com>" &&
 	git format-patch --stdout main..side >patch9 &&
 	sed -e "/^\$/q" patch9 >hdrs9 &&
-	grep "^To: \"R. E. Cipient\" <rcipient@example.com>\$" hdrs9
+	test_grep "^To: \"R. E. Cipient\" <rcipient@example.com>\$" hdrs9
 '
 
 test_expect_failure 'configuration To: header (rfc2047)' '
 	git config format.to "R Ä Cipient <rcipient@example.com>" &&
 	git format-patch --stdout main..side >patch9 &&
 	sed -e "/^\$/q" patch9 >hdrs9 &&
-	grep "^To: =?UTF-8?q?R=20=C3=84=20Cipient?= <rcipient@example.com>\$" hdrs9
+	test_grep "^To: =?UTF-8?q?R=20=C3=84=20Cipient?= <rcipient@example.com>\$" hdrs9
 '
 
 # check_patch <patch>: Verify that <patch> looks like a half-sane
@@ -250,35 +250,35 @@ test_expect_success 'format.from=false' '
 	git -c format.from=false format-patch --stdout main..side >patch &&
 	sed -e "/^\$/q" patch >hdrs &&
 	check_patch patch &&
-	! grep "^From: C O Mitter <committer@example.com>\$" hdrs
+	test_grep ! "^From: C O Mitter <committer@example.com>\$" hdrs
 '
 
 test_expect_success 'format.from=true' '
 	git -c format.from=true format-patch --stdout main..side >patch &&
 	sed -e "/^\$/q" patch >hdrs &&
 	check_patch hdrs &&
-	grep "^From: C O Mitter <committer@example.com>\$" hdrs
+	test_grep "^From: C O Mitter <committer@example.com>\$" hdrs
 '
 
 test_expect_success 'format.from with address' '
 	git -c format.from="F R Om <from@example.com>" format-patch --stdout main..side >patch &&
 	sed -e "/^\$/q" patch >hdrs &&
 	check_patch hdrs &&
-	grep "^From: F R Om <from@example.com>\$" hdrs
+	test_grep "^From: F R Om <from@example.com>\$" hdrs
 '
 
 test_expect_success '--no-from overrides format.from' '
 	git -c format.from="F R Om <from@example.com>" format-patch --no-from --stdout main..side >patch &&
 	sed -e "/^\$/q" patch >hdrs &&
 	check_patch hdrs &&
-	! grep "^From: F R Om <from@example.com>\$" hdrs
+	test_grep ! "^From: F R Om <from@example.com>\$" hdrs
 '
 
 test_expect_success '--from overrides format.from' '
 	git -c format.from="F R Om <from@example.com>" format-patch --from --stdout main..side >patch &&
 	sed -e "/^\$/q" patch >hdrs &&
 	check_patch hdrs &&
-	! grep "^From: F R Om <from@example.com>\$" hdrs
+	test_grep ! "^From: F R Om <from@example.com>\$" hdrs
 '
 
 test_expect_success '--no-to overrides config.to' '
@@ -287,7 +287,7 @@ test_expect_success '--no-to overrides config.to' '
 	git format-patch --no-to --stdout main..side >patch10 &&
 	sed -e "/^\$/q" patch10 >hdrs10 &&
 	check_patch hdrs10 &&
-	! grep "^To: R E Cipient <rcipient@example.com>\$" hdrs10
+	test_grep ! "^To: R E Cipient <rcipient@example.com>\$" hdrs10
 '
 
 test_expect_success '--no-to and --to replaces config.to' '
@@ -297,8 +297,8 @@ test_expect_success '--no-to and --to replaces config.to' '
 		--stdout main..side >patch11 &&
 	sed -e "/^\$/q" patch11 >hdrs11 &&
 	check_patch hdrs11 &&
-	! grep "^To: Someone <someone@out.there>\$" hdrs11 &&
-	grep "^To: Someone Else <else@out.there>\$" hdrs11
+	test_grep ! "^To: Someone <someone@out.there>\$" hdrs11 &&
+	test_grep "^To: Someone Else <else@out.there>\$" hdrs11
 '
 
 test_expect_success '--no-cc overrides config.cc' '
@@ -307,7 +307,7 @@ test_expect_success '--no-cc overrides config.cc' '
 	git format-patch --no-cc --stdout main..side >patch12 &&
 	sed -e "/^\$/q" patch12 >hdrs12 &&
 	check_patch hdrs12 &&
-	! grep "^Cc: C E Cipient <rcipient@example.com>\$" hdrs12
+	test_grep ! "^Cc: C E Cipient <rcipient@example.com>\$" hdrs12
 '
 
 test_expect_success '--no-add-header overrides config.headers' '
@@ -316,7 +316,7 @@ test_expect_success '--no-add-header overrides config.headers' '
 	git format-patch --no-add-header --stdout main..side >patch13 &&
 	sed -e "/^\$/q" patch13 >hdrs13 &&
 	check_patch hdrs13 &&
-	! grep "^Header1: B E Cipient <rcipient@example.com>\$" hdrs13
+	test_grep ! "^Header1: B E Cipient <rcipient@example.com>\$" hdrs13
 '
 
 test_expect_success 'multiple files' '
@@ -508,41 +508,41 @@ test_expect_success 'cover letter config commitlistformat not set' '
 test_expect_success 'reroll count' '
 	rm -fr patches &&
 	git format-patch -o patches --cover-letter --reroll-count 4 main..side >list &&
-	! grep -v "^patches/v4-000[0-3]-" list &&
+	test_grep ! -v "^patches/v4-000[0-3]-" list &&
 	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
-	! grep -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
+	test_grep ! -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
 '
 
 test_expect_success 'reroll count (-v)' '
 	rm -fr patches &&
 	git format-patch -o patches --cover-letter -v4 main..side >list &&
-	! grep -v "^patches/v4-000[0-3]-" list &&
+	test_grep ! -v "^patches/v4-000[0-3]-" list &&
 	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
-	! grep -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
+	test_grep ! -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
 '
 
 test_expect_success 'reroll count (-v) with a fractional number' '
 	rm -fr patches &&
 	git format-patch -o patches --cover-letter -v4.4 main..side >list &&
-	! grep -v "^patches/v4.4-000[0-3]-" list &&
+	test_grep ! -v "^patches/v4.4-000[0-3]-" list &&
 	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
-	! grep -v "^Subject: \[PATCH v4.4 [0-3]/3\] " subjects
+	test_grep ! -v "^Subject: \[PATCH v4.4 [0-3]/3\] " subjects
 '
 
 test_expect_success 'reroll (-v) count with a non number' '
 	rm -fr patches &&
 	git format-patch -o patches --cover-letter -v4rev2 main..side >list &&
-	! grep -v "^patches/v4rev2-000[0-3]-" list &&
+	test_grep ! -v "^patches/v4rev2-000[0-3]-" list &&
 	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
-	! grep -v "^Subject: \[PATCH v4rev2 [0-3]/3\] " subjects
+	test_grep ! -v "^Subject: \[PATCH v4rev2 [0-3]/3\] " subjects
 '
 
 test_expect_success 'reroll (-v) count with a non-pathname character' '
 	rm -fr patches &&
 	git format-patch -o patches --cover-letter -v4---..././../--1/.2//  main..side >list &&
-	! grep -v "patches/v4-\.-\.-\.-1-\.2-000[0-3]-" list &&
+	test_grep ! -v "patches/v4-\.-\.-\.-1-\.2-000[0-3]-" list &&
 	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
-	! grep -v "^Subject: \[PATCH v4---\.\.\./\./\.\./--1/\.2// [0-3]/3\] " subjects
+	test_grep ! -v "^Subject: \[PATCH v4---\.\.\./\./\.\./--1/\.2// [0-3]/3\] " subjects
 '
 
 check_threading () {
@@ -813,9 +813,9 @@ test_expect_success 'cover-letter inherits diff options' '
 	git commit -m foo &&
 	git format-patch --no-renames --cover-letter -1 &&
 	check_patch 0000-cover-letter.patch &&
-	! grep "file => foo .* 0 *\$" 0000-cover-letter.patch &&
+	test_grep ! "file => foo .* 0 *\$" 0000-cover-letter.patch &&
 	git format-patch --cover-letter -1 -M &&
-	grep "file => foo .* 0 *\$" 0000-cover-letter.patch
+	test_grep "file => foo .* 0 *\$" 0000-cover-letter.patch
 '
 
 cat >expect <<EOF
@@ -924,13 +924,13 @@ test_expect_success 'format-patch from a subdirectory (3)' '
 
 test_expect_success 'format-patch --in-reply-to' '
 	git format-patch -1 --stdout --in-reply-to "baz@foo.bar" >patch8 &&
-	grep "^In-Reply-To: <baz@foo.bar>" patch8 &&
-	grep "^References: <baz@foo.bar>" patch8
+	test_grep "^In-Reply-To: <baz@foo.bar>" patch8 &&
+	test_grep "^References: <baz@foo.bar>" patch8
 '
 
 test_expect_success 'format-patch --signoff' '
 	git format-patch -1 --signoff --stdout >out &&
-	grep "^Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>" out
+	test_grep "^Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>" out
 '
 
 test_expect_success 'format-patch --notes --signoff' '
@@ -949,27 +949,27 @@ test_expect_success 'format-patch notes output control' '
 	git notes add -m "notes config message" HEAD &&
 
 	git format-patch -1 --stdout >out &&
-	! grep "notes config message" out &&
+	test_grep ! "notes config message" out &&
 	git format-patch -1 --stdout --notes >out &&
-	grep "notes config message" out &&
+	test_grep "notes config message" out &&
 	git format-patch -1 --stdout --no-notes >out &&
-	! grep "notes config message" out &&
+	test_grep ! "notes config message" out &&
 	git format-patch -1 --stdout --notes --no-notes >out &&
-	! grep "notes config message" out &&
+	test_grep ! "notes config message" out &&
 	git format-patch -1 --stdout --no-notes --notes >out &&
-	grep "notes config message" out &&
+	test_grep "notes config message" out &&
 
 	test_config format.notes true &&
 	git format-patch -1 --stdout >out &&
-	grep "notes config message" out &&
+	test_grep "notes config message" out &&
 	git format-patch -1 --stdout --notes >out &&
-	grep "notes config message" out &&
+	test_grep "notes config message" out &&
 	git format-patch -1 --stdout --no-notes >out &&
-	! grep "notes config message" out &&
+	test_grep ! "notes config message" out &&
 	git format-patch -1 --stdout --notes --no-notes >out &&
-	! grep "notes config message" out &&
+	test_grep ! "notes config message" out &&
 	git format-patch -1 --stdout --no-notes --notes >out &&
-	grep "notes config message" out
+	test_grep "notes config message" out
 '
 
 test_expect_success 'format-patch with multiple notes refs' '
@@ -979,39 +979,39 @@ test_expect_success 'format-patch with multiple notes refs' '
 	git notes --ref note2 add -m "this is note 2" HEAD &&
 
 	git format-patch -1 --stdout >out &&
-	! grep "this is note 1" out &&
-	! grep "this is note 2" out &&
+	test_grep ! "this is note 1" out &&
+	test_grep ! "this is note 2" out &&
 	git format-patch -1 --stdout --notes=note1 >out &&
-	grep "this is note 1" out &&
-	! grep "this is note 2" out &&
+	test_grep "this is note 1" out &&
+	test_grep ! "this is note 2" out &&
 	git format-patch -1 --stdout --notes=note2 >out &&
-	! grep "this is note 1" out &&
-	grep "this is note 2" out &&
+	test_grep ! "this is note 1" out &&
+	test_grep "this is note 2" out &&
 	git format-patch -1 --stdout --notes=note1 --notes=note2 >out &&
-	grep "this is note 1" out &&
-	grep "this is note 2" out &&
+	test_grep "this is note 1" out &&
+	test_grep "this is note 2" out &&
 
 	test_config format.notes note1 &&
 	git format-patch -1 --stdout >out &&
-	grep "this is note 1" out &&
-	! grep "this is note 2" out &&
+	test_grep "this is note 1" out &&
+	test_grep ! "this is note 2" out &&
 	git format-patch -1 --stdout --no-notes >out &&
-	! grep "this is note 1" out &&
-	! grep "this is note 2" out &&
+	test_grep ! "this is note 1" out &&
+	test_grep ! "this is note 2" out &&
 	git format-patch -1 --stdout --notes=note2 >out &&
-	grep "this is note 1" out &&
-	grep "this is note 2" out &&
+	test_grep "this is note 1" out &&
+	test_grep "this is note 2" out &&
 	git format-patch -1 --stdout --no-notes --notes=note2 >out &&
-	! grep "this is note 1" out &&
-	grep "this is note 2" out &&
+	test_grep ! "this is note 1" out &&
+	test_grep "this is note 2" out &&
 
 	git config --add format.notes note2 &&
 	git format-patch -1 --stdout >out &&
-	grep "this is note 1" out &&
-	grep "this is note 2" out &&
+	test_grep "this is note 1" out &&
+	test_grep "this is note 2" out &&
 	git format-patch -1 --stdout --no-notes >out &&
-	! grep "this is note 1" out &&
-	! grep "this is note 2" out
+	test_grep ! "this is note 1" out &&
+	test_grep ! "this is note 2" out
 '
 
 test_expect_success 'format-patch with multiple notes refs in config' '
@@ -1024,26 +1024,26 @@ test_expect_success 'format-patch with multiple notes refs in config' '
 
 	git config format.notes note1 &&
 	git format-patch -1 --stdout >out &&
-	grep "this is note 1" out &&
-	! grep "this is note 2" out &&
+	test_grep "this is note 1" out &&
+	test_grep ! "this is note 2" out &&
 	git config format.notes note2 &&
 	git format-patch -1 --stdout >out &&
-	! grep "this is note 1" out &&
-	grep "this is note 2" out &&
+	test_grep ! "this is note 1" out &&
+	test_grep "this is note 2" out &&
 	git config --add format.notes note1 &&
 	git format-patch -1 --stdout >out &&
-	grep "this is note 1" out &&
-	grep "this is note 2" out &&
+	test_grep "this is note 1" out &&
+	test_grep "this is note 2" out &&
 
 	git config --replace-all format.notes note1 &&
 	git config --add format.notes false &&
 	git format-patch -1 --stdout >out &&
-	! grep "this is note 1" out &&
-	! grep "this is note 2" out &&
+	test_grep ! "this is note 1" out &&
+	test_grep ! "this is note 2" out &&
 	git config --add format.notes note2 &&
 	git format-patch -1 --stdout >out &&
-	! grep "this is note 1" out &&
-	grep "this is note 2" out
+	test_grep ! "this is note 1" out &&
+	test_grep "this is note 2" out
 '
 
 echo "fatal: --name-only does not make sense" >expect.name-only
@@ -1095,7 +1095,7 @@ test_expect_success 'format-patch -- <path>' '
 
 	git format-patch main..pathspec -- file_a >output &&
 	test_cmp expect output &&
-	! grep file_b *.patch
+	test_grep ! file_b *.patch
 '
 
 test_expect_success 'format-patch --ignore-if-in-upstream HEAD' '
@@ -1129,14 +1129,14 @@ test_expect_success 'format-patch --signature' '
 test_expect_success 'format-patch with format.signature config' '
 	git config format.signature "config sig" &&
 	git format-patch --stdout -1 >output &&
-	grep "config sig" output
+	test_grep "config sig" output
 '
 
 test_expect_success 'format-patch --signature overrides format.signature' '
 	git config format.signature "config sig" &&
 	git format-patch --stdout --signature="overrides" -1 >output &&
-	! grep "config sig" output &&
-	grep "overrides" output
+	test_grep ! "config sig" output &&
+	test_grep "overrides" output
 '
 
 test_expect_success 'format-patch --no-signature ignores format.signature' '
@@ -1144,9 +1144,9 @@ test_expect_success 'format-patch --no-signature ignores format.signature' '
 	git format-patch --stdout --signature="my sig" --no-signature \
 		-1 >output &&
 	check_patch output &&
-	! grep "config sig" output &&
-	! grep "my sig" output &&
-	! grep "^-- \$" output
+	test_grep ! "config sig" output &&
+	test_grep ! "my sig" output &&
+	test_grep ! "^-- \$" output
 '
 
 test_expect_success 'format-patch --signature --cover-letter' '
@@ -1161,20 +1161,20 @@ test_expect_success 'format.signature="" suppresses signatures' '
 	git config format.signature "" &&
 	git format-patch --stdout -1 >output &&
 	check_patch output &&
-	! grep "^-- \$" output
+	test_grep ! "^-- \$" output
 '
 
 test_expect_success 'format-patch --no-signature suppresses signatures' '
 	git config --unset-all format.signature &&
 	git format-patch --stdout --no-signature -1 >output &&
 	check_patch output &&
-	! grep "^-- \$" output
+	test_grep ! "^-- \$" output
 '
 
 test_expect_success 'format-patch --signature="" suppresses signatures' '
 	git format-patch --stdout --signature="" -1 >output &&
 	check_patch output &&
-	! grep "^-- \$" output
+	test_grep ! "^-- \$" output
 '
 
 test_expect_success 'prepare mail-signature input' '
@@ -1213,7 +1213,7 @@ test_expect_success '--no-signature suppresses format.signaturefile ' '
 	test_config format.signaturefile mail-signature &&
 	git format-patch --stdout --no-signature -1 >output &&
 	check_patch output &&
-	! grep "^-- \$" output
+	test_grep ! "^-- \$" output
 '
 
 test_expect_success '--signature-file overrides format.signaturefile' '
@@ -1235,7 +1235,7 @@ test_expect_success '--signature overrides format.signaturefile' '
 	test_config format.signaturefile mail-signature &&
 	git format-patch --stdout --signature="my sig" -1 >output &&
 	check_patch output &&
-	grep "my sig" output
+	test_grep "my sig" output
 '
 
 test_expect_success TTY 'format-patch --stdout paginates' '
@@ -2001,10 +2001,10 @@ body" &&
 	test_config format.coverFromDescription default &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with --cover-from-description default' '
@@ -2013,10 +2013,10 @@ test_expect_success 'cover letter with --cover-from-description default' '
 body" &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description default main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with format.coverFromDescription = none' '
@@ -2026,10 +2026,10 @@ body" &&
 	test_config format.coverFromDescription none &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	! grep "^config subject$" actual &&
-	! grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep ! "^config subject$" actual &&
+	test_grep ! "^body$" actual
 '
 
 test_expect_success 'cover letter with --cover-from-description none' '
@@ -2038,10 +2038,10 @@ test_expect_success 'cover letter with --cover-from-description none' '
 body" &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description none main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	! grep "^config subject$" actual &&
-	! grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep ! "^config subject$" actual &&
+	test_grep ! "^body$" actual
 '
 
 test_expect_success 'cover letter with format.coverFromDescription = message' '
@@ -2051,10 +2051,10 @@ body" &&
 	test_config format.coverFromDescription message &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with --cover-from-description message' '
@@ -2063,10 +2063,10 @@ test_expect_success 'cover letter with --cover-from-description message' '
 body" &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description message main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with format.coverFromDescription = subject' '
@@ -2076,10 +2076,10 @@ body" &&
 	test_config format.coverFromDescription subject &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter main >actual &&
-	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	! grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep ! "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with --cover-from-description subject' '
@@ -2088,10 +2088,10 @@ test_expect_success 'cover letter with --cover-from-description subject' '
 body" &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description subject main >actual &&
-	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	! grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep ! "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with --cover-from-description subject (UTF-8 subject line)' '
@@ -2100,8 +2100,8 @@ test_expect_success 'cover letter with --cover-from-description subject (UTF-8 s
 body" &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description subject --encode-email-headers main >actual &&
-	grep "^Subject: \[PATCH 0/2\] =?UTF-8?q?Caf=C3=A9=3F?=$" actual &&
-	! grep "Café" actual
+	test_grep "^Subject: \[PATCH 0/2\] =?UTF-8?q?Caf=C3=A9=3F?=$" actual &&
+	test_grep ! "Café" actual
 '
 
 test_expect_success 'cover letter with format.coverFromDescription = auto (short subject line)' '
@@ -2111,10 +2111,10 @@ body" &&
 	test_config format.coverFromDescription auto &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter main >actual &&
-	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	! grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep ! "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with --cover-from-description auto (short subject line)' '
@@ -2123,10 +2123,10 @@ test_expect_success 'cover letter with --cover-from-description auto (short subj
 body" &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description auto main >actual &&
-	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	! grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep ! "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with format.coverFromDescription = auto (long subject line)' '
@@ -2136,10 +2136,10 @@ body" &&
 	test_config format.coverFromDescription auto &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	grep "^this is a really long first line and it is over 100 characters long which is the threshold for long subjects$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep "^this is a really long first line and it is over 100 characters long which is the threshold for long subjects$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with --cover-from-description auto (long subject line)' '
@@ -2148,10 +2148,10 @@ test_expect_success 'cover letter with --cover-from-description auto (long subje
 body" &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description auto main >actual &&
-	grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	grep "^this is a really long first line and it is over 100 characters long which is the threshold for long subjects$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] \*\*\* SUBJECT HERE \*\*\*$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep "^this is a really long first line and it is over 100 characters long which is the threshold for long subjects$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter with command-line --cover-from-description overrides config' '
@@ -2161,52 +2161,52 @@ body" &&
 	test_config format.coverFromDescription none &&
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description subject main >actual &&
-	grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
-	! grep "^\*\*\* BLURB HERE \*\*\*$" actual &&
-	! grep "^config subject$" actual &&
-	grep "^body$" actual
+	test_grep "^Subject: \[PATCH 0/2\] config subject$" actual &&
+	test_grep ! "^\*\*\* BLURB HERE \*\*\*$" actual &&
+	test_grep ! "^config subject$" actual &&
+	test_grep "^body$" actual
 '
 
 test_expect_success 'cover letter using branch description (1)' '
 	git checkout rebuild-1 &&
 	test_config branch.rebuild-1.description hello &&
 	git format-patch --stdout --cover-letter main >actual &&
-	grep hello actual
+	test_grep hello actual
 '
 
 test_expect_success 'cover letter using branch description (2)' '
 	git checkout rebuild-1 &&
 	test_config branch.rebuild-1.description hello &&
 	git format-patch --stdout --cover-letter rebuild-1~2..rebuild-1 >actual &&
-	grep hello actual
+	test_grep hello actual
 '
 
 test_expect_success 'cover letter using branch description (3)' '
 	git checkout rebuild-1 &&
 	test_config branch.rebuild-1.description hello &&
 	git format-patch --stdout --cover-letter ^main rebuild-1 >actual &&
-	grep hello actual
+	test_grep hello actual
 '
 
 test_expect_success 'cover letter using branch description (4)' '
 	git checkout rebuild-1 &&
 	test_config branch.rebuild-1.description hello &&
 	git format-patch --stdout --cover-letter main.. >actual &&
-	grep hello actual
+	test_grep hello actual
 '
 
 test_expect_success 'cover letter using branch description (5)' '
 	git checkout rebuild-1 &&
 	test_config branch.rebuild-1.description hello &&
 	git format-patch --stdout --cover-letter -2 HEAD >actual &&
-	grep hello actual
+	test_grep hello actual
 '
 
 test_expect_success 'cover letter using branch description (6)' '
 	git checkout rebuild-1 &&
 	test_config branch.rebuild-1.description hello &&
 	git format-patch --stdout --cover-letter -2 >actual &&
-	grep hello actual
+	test_grep hello actual
 '
 
 test_expect_success 'cover letter with --description-file' '
@@ -2219,8 +2219,8 @@ test_expect_success 'cover letter with --description-file' '
 	git checkout rebuild-1 &&
 	git format-patch --stdout --cover-letter --cover-from-description auto \
 		--description-file description.txt main >actual &&
-	grep "^Subject: \[PATCH 0/2\] subject from file$" actual &&
-	grep "^body from file$" actual
+	test_grep "^Subject: \[PATCH 0/2\] subject from file$" actual &&
+	test_grep "^body from file$" actual
 '
 
 test_expect_success 'cover letter with nothing' '
@@ -2467,7 +2467,7 @@ test_expect_success 'format-patch errors out when history involves criss-cross'
 test_expect_success 'format-patch format.useAutoBase whenAble history involves criss-cross' '
 	test_config format.useAutoBase whenAble &&
 	git format-patch -1 >patch &&
-	! grep "^base-commit:" patch
+	test_grep ! "^base-commit:" patch
 '
 
 test_expect_success 'format-patch format.useAutoBase option' '
@@ -2502,13 +2502,13 @@ test_expect_success 'format-patch --base overrides format.useAutoBase' '
 test_expect_success 'format-patch --no-base overrides format.useAutoBase' '
 	test_config format.useAutoBase true &&
 	git format-patch --stdout --no-base -1 >patch &&
-	! grep "^base-commit:" patch
+	test_grep ! "^base-commit:" patch
 '
 
 test_expect_success 'format-patch --no-base overrides format.useAutoBase whenAble' '
 	test_config format.useAutoBase whenAble &&
 	git format-patch --stdout --no-base -1 >patch &&
-	! grep "^base-commit:" patch
+	test_grep ! "^base-commit:" patch
 '
 
 test_expect_success 'format-patch --base with --attach' '
@@ -2521,7 +2521,7 @@ test_expect_success 'format-patch --base with --attach' '
 test_expect_success 'format-patch --attach cover-letter only is non-multipart' '
 	test_when_finished "rm -fr patches" &&
 	git format-patch -o patches --cover-letter --attach=mimemime --base=HEAD~ -1 &&
-	! grep -E "^--+mimemime" patches/0000*.patch &&
+	test_grep ! -E "^--+mimemime" patches/0000*.patch &&
 	grep -E "^--+mimemime$" patches/0001*.patch >output &&
 	test_line_count = 2 output &&
 	grep -E "^--+mimemime--$" patches/0001*.patch >output &&
@@ -2533,7 +2533,7 @@ test_expect_success 'format-patch with format.attach' '
 	separator=attachment-separator &&
 	test_config format.attach "$separator" &&
 	filename=$(git format-patch -o patches -1) &&
-	grep "^Content-Type: multipart/.*$separator" "$filename"
+	test_grep "^Content-Type: multipart/.*$separator" "$filename"
 '
 
 test_expect_success 'format-patch with format.attach=disabled' '
@@ -2543,7 +2543,7 @@ test_expect_success 'format-patch with format.attach=disabled' '
 	test_config format.attach "" &&
 	filename=$(git format-patch -o patches -1) &&
 	# The output should not even declare content type for text/plain.
-	! grep "^Content-Type: multipart/" "$filename"
+	test_grep ! "^Content-Type: multipart/" "$filename"
 '
 
 test_expect_success '-c format.mboxrd format-patch' '
@@ -2674,23 +2674,23 @@ test_expect_success 'interdiff: explicit --no-cover-letter defeats implied --cov
 
 test_expect_success 'format-patch does not respect diff.noprefix' '
 	git -c diff.noprefix format-patch -1 --stdout >actual &&
-	grep "^--- a/blorp" actual
+	test_grep "^--- a/blorp" actual
 '
 
 test_expect_success 'format-patch respects format.noprefix' '
 	git -c format.noprefix format-patch -1 --stdout >actual &&
-	grep "^--- blorp" actual
+	test_grep "^--- blorp" actual
 '
 
 test_expect_success 'format.noprefix=false' '
 	git -c format.noprefix=false format-patch -1 --stdout >actual &&
-	grep "^--- a/blorp" actual
+	test_grep "^--- a/blorp" actual
 '
 
 test_expect_success 'format-patch --default-prefix overrides format.noprefix' '
 	git -c format.noprefix \
 		format-patch -1 --default-prefix --stdout >actual &&
-	grep "^--- a/blorp" actual
+	test_grep "^--- a/blorp" actual
 '
 
 test_expect_success 'errors on format.noprefix which is not boolean' '
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index b691d29479..6e7ba8abf6 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -638,14 +638,14 @@ test_expect_success 'check mixed spaces and tabs in indent' '
 	# This is indented with SP HT SP.
 	echo " 	 foo();" >x &&
 	test_must_fail git diff --check >check &&
-	grep "space before tab in indent" check
+	test_grep "space before tab in indent" check
 '
 
 test_expect_success 'check mixed tabs and spaces in indent' '
 	# This is indented with HT SP HT.
 	echo "	 	foo();" >x &&
 	test_must_fail git diff --check >check &&
-	grep "space before tab in indent" check
+	test_grep "space before tab in indent" check
 '
 
 test_expect_success 'check with no whitespace errors' '
@@ -891,14 +891,14 @@ test_expect_success 'line numbers in --check output are correct' '
 	echo "" >x &&
 	echo "foo(); " >>x &&
 	test_must_fail git diff --check >check &&
-	grep "x:2:" check
+	test_grep "x:2:" check
 '
 
 test_expect_success 'checkdiff detects new trailing blank lines (1)' '
 	echo "foo();" >x &&
 	echo "" >>x &&
 	test_must_fail git diff --check >check &&
-	grep "new blank line" check
+	test_grep "new blank line" check
 '
 
 test_expect_success 'checkdiff detects new trailing blank lines (2)' '
@@ -906,7 +906,7 @@ test_expect_success 'checkdiff detects new trailing blank lines (2)' '
 	git add x &&
 	test_write_lines a "" "" "" "" >x &&
 	test_must_fail git diff --check >check &&
-	grep "new blank line" check
+	test_grep "new blank line" check
 '
 
 test_expect_success 'checkdiff allows new blank lines' '
@@ -1018,7 +1018,7 @@ test_expect_success 'combined diff with autocrlf conversion' '
 
 	git diff >actual.raw &&
 	sed -e "1,/^@@@/d" actual.raw >actual &&
-	! grep "^-" actual
+	test_grep ! "^-" actual
 
 '
 
@@ -2166,8 +2166,8 @@ test_expect_success 'move detection with submodules' '
 
 	# no move detection as the moved line is across repository boundaries.
 	test_decode_color <actual >decoded_actual &&
-	! grep BGREEN decoded_actual &&
-	! grep BRED decoded_actual &&
+	test_grep ! BGREEN decoded_actual &&
+	test_grep ! BRED decoded_actual &&
 
 	# nor did we mess with it another way
 	git diff --submodule=diff --color >expect.raw &&
diff --git a/t/t4017-diff-retval.sh b/t/t4017-diff-retval.sh
index c2863c99b7..5ec6f5c612 100755
--- a/t/t4017-diff-retval.sh
+++ b/t/t4017-diff-retval.sh
@@ -139,7 +139,7 @@ test_expect_success 'check honors conflict marker length' '
 
 test_expect_success 'option errors are not confused by --exit-code' '
 	test_must_fail git diff --exit-code --nonsense 2>err &&
-	grep '^usage:' err
+	test_grep '^usage:' err
 '
 
 for option in --exit-code --quiet
diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index e026fac1f4..b538b715f5 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh
@@ -115,7 +115,7 @@ for i in $(git ls-files)
 do
 	test_expect_success "hunk header: $i" "
 		git diff -U1 $i >actual &&
-		grep '@@ .* @@.*RIGHT' actual
+		test_grep '@@ .* @@.*RIGHT' actual
 	"
 done
 
diff --git a/t/t4019-diff-wserror.sh b/t/t4019-diff-wserror.sh
index 4001dacee3..939ec8a0b4 100755
--- a/t/t4019-diff-wserror.sh
+++ b/t/t4019-diff-wserror.sh
@@ -251,8 +251,8 @@ test_expect_success 'trailing empty lines (1)' '
 
 	rm -f .gitattributes &&
 	test_must_fail git diff --check >output &&
-	grep "new blank line at" output &&
-	grep "trailing whitespace" output
+	test_grep "new blank line at" output &&
+	test_grep "trailing whitespace" output
 
 '
 
@@ -280,8 +280,8 @@ test_expect_success 'do not color trailing cr in context' '
 	git add G &&
 	echo BBBQ | tr Q "\015" >>G &&
 	git diff --color G | tr "\015" Q >output &&
-	grep "BBB.*${blue_grep}Q" output &&
-	grep "AAA.*\[mQ" output
+	test_grep "BBB.*${blue_grep}Q" output &&
+	test_grep "AAA.*\[mQ" output
 
 '
 
diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index 7ec5854f74..93d37230c6 100755
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -34,13 +34,13 @@ test_expect_success 'GIT_EXTERNAL_DIFF environment' '
 
 test_expect_success 'GIT_EXTERNAL_DIFF environment should apply only to diff' '
 	GIT_EXTERNAL_DIFF=echo git log -p -1 HEAD >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 
 '
 
 test_expect_success 'GIT_EXTERNAL_DIFF environment and --no-ext-diff' '
 	GIT_EXTERNAL_DIFF=echo git diff --no-ext-diff >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 
 '
 
@@ -86,13 +86,13 @@ test_expect_success 'diff.external' '
 test_expect_success 'diff.external should apply only to diff' '
 	test_config diff.external echo &&
 	git log -p -1 HEAD >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 '
 
 test_expect_success 'diff.external and --no-ext-diff' '
 	test_config diff.external echo &&
 	git diff --no-ext-diff >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 '
 
 test_expect_success 'diff attribute' '
@@ -113,13 +113,13 @@ test_expect_success 'diff attribute' '
 
 test_expect_success 'diff attribute should apply only to diff' '
 	git log -p -1 HEAD >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 
 '
 
 test_expect_success 'diff attribute and --no-ext-diff' '
 	git diff --no-ext-diff >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 
 '
 
@@ -140,13 +140,13 @@ test_expect_success 'diff attribute' '
 
 test_expect_success 'diff attribute should apply only to diff' '
 	git log -p -1 HEAD >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 
 '
 
 test_expect_success 'diff attribute and --no-ext-diff' '
 	git diff --no-ext-diff >out &&
-	grep "^diff --git a/file b/file" out
+	test_grep "^diff --git a/file b/file" out
 
 '
 
@@ -178,7 +178,7 @@ test_expect_success 'attributes trump GIT_EXTERNAL_DIFF and diff.external' '
 test_expect_success 'no diff with -diff' '
 	echo >.gitattributes "file -diff" &&
 	git diff >out &&
-	grep Binary out
+	test_grep Binary out
 '
 
 check_external_diff () {
diff --git a/t/t4021-format-patch-numbered.sh b/t/t4021-format-patch-numbered.sh
index 9be65fd444..204851f061 100755
--- a/t/t4021-format-patch-numbered.sh
+++ b/t/t4021-format-patch-numbered.sh
@@ -94,7 +94,7 @@ test_expect_success 'format.numbered && --no-numbered' '
 test_expect_success 'format.numbered && --keep-subject' '
 
 	git format-patch --keep-subject --stdout HEAD^ >patch4a &&
-	grep "^Subject: Third" patch4a
+	test_grep "^Subject: Third" patch4a
 
 '
 
@@ -123,7 +123,7 @@ test_expect_success 'format.numbered = auto && --no-numbered' '
 test_expect_success '--start-number && --numbered' '
 
 	git format-patch --start-number 3 --numbered --stdout HEAD~1 > patch8 &&
-	grep "^Subject: \[PATCH 3/3\]" patch8
+	test_grep "^Subject: \[PATCH 3/3\]" patch8
 '
 
 test_expect_success 'single patch with cover-letter defaults to numbers' '
diff --git a/t/t4022-diff-rewrite.sh b/t/t4022-diff-rewrite.sh
index 6fed993ea0..b5c1b6868f 100755
--- a/t/t4022-diff-rewrite.sh
+++ b/t/t4022-diff-rewrite.sh
@@ -58,13 +58,13 @@ test_expect_success 'suppress deletion diff with -D' '
 test_expect_success 'show deletion diff with -B' '
 
 	git diff -B -- test >actual &&
-	grep "Linus Torvalds" actual
+	test_grep "Linus Torvalds" actual
 '
 
 test_expect_success 'suppress deletion diff with -B -D' '
 
 	git diff -B -D -- test >actual &&
-	grep -v "Linus Torvalds" actual
+	test_grep -v "Linus Torvalds" actual
 '
 
 test_expect_success 'prepare a file that ends with an incomplete line' '
@@ -82,19 +82,19 @@ test_expect_success 'rewrite the middle 90% of sequence file and terminate with
 
 test_expect_success 'confirm that sequence file is considered a rewrite' '
 	git diff -B seq >res &&
-	grep "dissimilarity index" res
+	test_grep "dissimilarity index" res
 '
 
 test_expect_success 'no newline at eof is on its own line without -B' '
 	git diff seq >res &&
-	grep "^\\\\ " res &&
-	! grep "^..*\\\\ " res
+	test_grep "^\\\\ " res &&
+	test_grep ! "^..*\\\\ " res
 '
 
 test_expect_success 'no newline at eof is on its own line with -B' '
 	git diff -B seq >res &&
-	grep "^\\\\ " res &&
-	! grep "^..*\\\\ " res
+	test_grep "^\\\\ " res &&
+	test_grep ! "^..*\\\\ " res
 '
 
 test_done
diff --git a/t/t4028-format-patch-mime-headers.sh b/t/t4028-format-patch-mime-headers.sh
index a06a747926..39344cf761 100755
--- a/t/t4028-format-patch-mime-headers.sh
+++ b/t/t4028-format-patch-mime-headers.sh
@@ -17,15 +17,15 @@ test_expect_success 'create commit with utf-8 body' '
 test_expect_success 'patch has mime headers' '
 	rm -f 0001-two.patch &&
 	git format-patch HEAD^ &&
-	grep -i "content-type: text/plain; charset=utf-8" 0001-two.patch
+	test_grep -i "content-type: text/plain; charset=utf-8" 0001-two.patch
 '
 
 test_expect_success 'patch has mime and extra headers' '
 	rm -f 0001-two.patch &&
 	git config format.headers "x-foo: bar" &&
 	git format-patch HEAD^ &&
-	grep -i "x-foo: bar" 0001-two.patch &&
-	grep -i "content-type: text/plain; charset=utf-8" 0001-two.patch
+	test_grep -i "x-foo: bar" 0001-two.patch &&
+	test_grep -i "content-type: text/plain; charset=utf-8" 0001-two.patch
 '
 
 test_done
diff --git a/t/t4031-diff-rewrite-binary.sh b/t/t4031-diff-rewrite-binary.sh
index 15e012ccc7..5b31ca02fe 100755
--- a/t/t4031-diff-rewrite-binary.sh
+++ b/t/t4031-diff-rewrite-binary.sh
@@ -29,32 +29,32 @@ test_expect_success 'create binary file with changes' '
 
 test_expect_success 'vanilla diff is binary' '
 	git diff >diff &&
-	grep "Binary files a/file and b/file differ" diff
+	test_grep "Binary files a/file and b/file differ" diff
 '
 
 test_expect_success 'rewrite diff is binary' '
 	git diff -B >diff &&
-	grep "dissimilarity index" diff &&
-	grep "Binary files a/file and b/file differ" diff
+	test_grep "dissimilarity index" diff &&
+	test_grep "Binary files a/file and b/file differ" diff
 '
 
 test_expect_success 'rewrite diff can show binary patch' '
 	git diff -B --binary >diff &&
-	grep "dissimilarity index" diff &&
-	grep "GIT binary patch" diff
+	test_grep "dissimilarity index" diff &&
+	test_grep "GIT binary patch" diff
 '
 
 test_expect_success 'rewrite diff --numstat shows binary changes' '
 	git diff -B --numstat --summary >diff &&
-	grep -e "-	-	" diff &&
-	grep " rewrite file" diff
+	test_grep -e "-	-	" diff &&
+	test_grep " rewrite file" diff
 '
 
 test_expect_success 'diff --stat counts binary rewrite as 0 lines' '
 	git diff -B --stat --summary >diff &&
-	grep "Bin" diff &&
+	test_grep "Bin" diff &&
 	test_grep "0 insertions.*0 deletions" diff &&
-	grep " rewrite file" diff
+	test_grep " rewrite file" diff
 '
 
 test_expect_success 'setup textconv' '
diff --git a/t/t4033-diff-patience.sh b/t/t4033-diff-patience.sh
index 113304dc59..8002c0f434 100755
--- a/t/t4033-diff-patience.sh
+++ b/t/t4033-diff-patience.sh
@@ -10,7 +10,7 @@ test_expect_success '--ignore-space-at-eol with a single appended character' '
 	printf "a\nbX\nc\n" >post &&
 	test_must_fail git diff --no-index \
 		--patience --ignore-space-at-eol pre post >diff &&
-	grep "^+.*X" diff
+	test_grep "^+.*X" diff
 '
 
 test_diff_frobnitz "patience"
diff --git a/t/t4036-format-patch-signer-mime.sh b/t/t4036-format-patch-signer-mime.sh
index 98d9713d8b..f57d3dc9fb 100755
--- a/t/t4036-format-patch-signer-mime.sh
+++ b/t/t4036-format-patch-signer-mime.sh
@@ -19,14 +19,14 @@ test_expect_success setup '
 test_expect_success 'format normally' '
 
 	git format-patch --stdout -1 >output &&
-	! grep Content-Type output
+	test_grep ! Content-Type output
 
 '
 
 test_expect_success 'format with signoff without funny signer name' '
 
 	git format-patch -s --stdout -1 >output &&
-	! grep Content-Type output
+	test_grep ! Content-Type output
 
 '
 
@@ -34,7 +34,7 @@ test_expect_success 'format with non ASCII signer name' '
 
 	GIT_COMMITTER_NAME="はまの ふにおう" \
 	git format-patch -s --stdout -1 >output &&
-	grep Content-Type output
+	test_grep Content-Type output
 
 '
 
diff --git a/t/t4038-diff-combined.sh b/t/t4038-diff-combined.sh
index 2ce26e585c..e11b711388 100755
--- a/t/t4038-diff-combined.sh
+++ b/t/t4038-diff-combined.sh
@@ -100,7 +100,7 @@ test_expect_success 'diagnose truncated file' '
 	git add file &&
 	git commit --amend -C HEAD &&
 	git show >out &&
-	grep "diff --cc file" out
+	test_grep "diff --cc file" out
 '
 
 test_expect_success 'setup for --cc --raw' '
@@ -118,13 +118,13 @@ test_expect_success 'check --cc --raw with four trees' '
 	four_trees=$(echo "$trees" | sed -e 4q) &&
 	git diff --cc --raw $four_trees $base_tree >out &&
 	# Check for four leading colons in the output:
-	grep "^::::[^:]" out
+	test_grep "^::::[^:]" out
 '
 
 test_expect_success 'check --cc --raw with forty trees' '
 	git diff --cc --raw $trees $base_tree >out &&
 	# Check for forty leading colons in the output:
-	grep "^::::::::::::::::::::::::::::::::::::::::[^:]" out
+	test_grep "^::::::::::::::::::::::::::::::::::::::::[^:]" out
 '
 
 test_expect_success 'setup combined ignore spaces' '
diff --git a/t/t4051-diff-function-context.sh b/t/t4051-diff-function-context.sh
index 4838a1df8b..117eaede8a 100755
--- a/t/t4051-diff-function-context.sh
+++ b/t/t4051-diff-function-context.sh
@@ -86,15 +86,15 @@ test_expect_success 'setup' '
 check_diff changed_hello 'changed function'
 
 test_expect_success ' context includes comment' '
-	grep "^ .*Hello comment" changed_hello.diff
+	test_grep "^ .*Hello comment" changed_hello.diff
 '
 
 test_expect_success ' context includes begin' '
-	grep "^ .*Begin of hello" changed_hello.diff
+	test_grep "^ .*Begin of hello" changed_hello.diff
 '
 
 test_expect_success ' context includes end' '
-	grep "^ .*End of hello" changed_hello.diff
+	test_grep "^ .*End of hello" changed_hello.diff
 '
 
 test_expect_success ' context does not include other functions' '
@@ -112,11 +112,11 @@ test_expect_success ' context does not include trailing empty lines' '
 check_diff changed_includes 'changed includes'
 
 test_expect_success ' context includes begin' '
-	grep "^ .*Begin.h" changed_includes.diff
+	test_grep "^ .*Begin.h" changed_includes.diff
 '
 
 test_expect_success ' context includes end' '
-	grep "^ .*End.h" changed_includes.diff
+	test_grep "^ .*End.h" changed_includes.diff
 '
 
 test_expect_success ' context does not include other functions' '
@@ -130,11 +130,11 @@ test_expect_success ' context does not include trailing empty lines' '
 check_diff appended 'appended function'
 
 test_expect_success ' context includes begin' '
-	grep "^[+].*Begin of first part" appended.diff
+	test_grep "^[+].*Begin of first part" appended.diff
 '
 
 test_expect_success ' context includes end' '
-	grep "^[+].*End of first part" appended.diff
+	test_grep "^[+].*End of first part" appended.diff
 '
 
 test_expect_success ' context does not include other functions' '
@@ -144,11 +144,11 @@ test_expect_success ' context does not include other functions' '
 check_diff extended 'appended function part'
 
 test_expect_success ' context includes begin' '
-	grep "^ .*Begin of first part" extended.diff
+	test_grep "^ .*Begin of first part" extended.diff
 '
 
 test_expect_success ' context includes end' '
-	grep "^[+].*End of second part" extended.diff
+	test_grep "^[+].*End of second part" extended.diff
 '
 
 test_expect_success ' context does not include other functions' '
@@ -162,11 +162,11 @@ test_expect_success ' context does not include preceding empty lines' '
 check_diff long_common_tail 'change with long common tail and no context' -U0
 
 test_expect_success ' context includes begin' '
-	grep "^ .*Begin of first part" long_common_tail.diff
+	test_grep "^ .*Begin of first part" long_common_tail.diff
 '
 
 test_expect_success ' context includes end' '
-	grep "^ .*End of second part" long_common_tail.diff
+	test_grep "^ .*End of second part" long_common_tail.diff
 '
 
 test_expect_success ' context does not include other functions' '
@@ -180,13 +180,13 @@ test_expect_success ' context does not include preceding empty lines' '
 check_diff changed_hello_appended 'changed function plus appended function'
 
 test_expect_success ' context includes begin' '
-	grep "^ .*Begin of hello" changed_hello_appended.diff &&
-	grep "^[+].*Begin of first part" changed_hello_appended.diff
+	test_grep "^ .*Begin of hello" changed_hello_appended.diff &&
+	test_grep "^[+].*Begin of first part" changed_hello_appended.diff
 '
 
 test_expect_success ' context includes end' '
-	grep "^ .*End of hello" changed_hello_appended.diff &&
-	grep "^[+].*End of first part" changed_hello_appended.diff
+	test_grep "^ .*End of hello" changed_hello_appended.diff &&
+	test_grep "^[+].*End of first part" changed_hello_appended.diff
 '
 
 test_expect_success ' context does not include other functions' '
@@ -196,13 +196,13 @@ test_expect_success ' context does not include other functions' '
 check_diff changed_hello_dummy 'changed two consecutive functions'
 
 test_expect_success ' context includes begin' '
-	grep "^ .*Begin of hello" changed_hello_dummy.diff &&
-	grep "^ .*Begin of dummy" changed_hello_dummy.diff
+	test_grep "^ .*Begin of hello" changed_hello_dummy.diff &&
+	test_grep "^ .*Begin of dummy" changed_hello_dummy.diff
 '
 
 test_expect_success ' context includes end' '
-	grep "^ .*End of hello" changed_hello_dummy.diff &&
-	grep "^ .*End of dummy" changed_hello_dummy.diff
+	test_grep "^ .*End of hello" changed_hello_dummy.diff &&
+	test_grep "^ .*End of dummy" changed_hello_dummy.diff
 '
 
 test_expect_success ' overlapping hunks are merged' '
diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh
index 15076dfe0d..8e0394cf5a 100755
--- a/t/t4053-diff-no-index.sh
+++ b/t/t4053-diff-no-index.sh
@@ -283,14 +283,14 @@ test_expect_success "diff --no-index -R treats '-' as stdin" '
 
 test_expect_success 'diff --no-index refuses to diff stdin and a directory' '
 	test_must_fail git diff --no-index -- - a </dev/null 2>err &&
-	grep "fatal: cannot compare stdin to a directory" err
+	test_grep "fatal: cannot compare stdin to a directory" err
 '
 
 test_expect_success PIPE 'diff --no-index refuses to diff a named pipe and a directory' '
 	test_when_finished "rm -f pipe" &&
 	mkfifo pipe &&
 	test_must_fail git diff --no-index -- pipe a 2>err &&
-	grep "fatal: cannot compare a named pipe to a directory" err
+	test_grep "fatal: cannot compare a named pipe to a directory" err
 '
 
 test_expect_success PIPE,SYMLINKS 'diff --no-index reads from pipes' '
diff --git a/t/t4063-diff-blobs.sh b/t/t4063-diff-blobs.sh
index 50fdb5ea52..1318cceb19 100755
--- a/t/t4063-diff-blobs.sh
+++ b/t/t4063-diff-blobs.sh
@@ -47,7 +47,7 @@ test_expect_success 'sha1 diff uses arguments as paths' '
 	check_paths $sha1_one $sha1_two
 '
 test_expect_success 'sha1 diff has no mode change' '
-	! grep mode diff
+	test_grep ! mode diff
 '
 
 test_expect_success 'diff by tree:path (run)' '
diff --git a/t/t4065-diff-anchored.sh b/t/t4065-diff-anchored.sh
index b3f510f040..9f06ac65be 100755
--- a/t/t4065-diff-anchored.sh
+++ b/t/t4065-diff-anchored.sh
@@ -10,11 +10,11 @@ test_expect_success '--anchored' '
 
 	# normally, c is moved to produce the smallest diff
 	test_expect_code 1 git diff --no-index pre post >diff &&
-	grep "^+c" diff &&
+	test_grep "^+c" diff &&
 
 	# with anchor, a is moved
 	test_expect_code 1 git diff --no-index --anchored=c pre post >diff &&
-	grep "^+a" diff
+	test_grep "^+a" diff
 '
 
 test_expect_success '--anchored multiple' '
@@ -23,13 +23,13 @@ test_expect_success '--anchored multiple' '
 
 	# with 1 anchor, c is not moved, but f is moved
 	test_expect_code 1 git diff --no-index --anchored=c pre post >diff &&
-	grep "^+a" diff && # a is moved instead of c
-	grep "^+f" diff &&
+	test_grep "^+a" diff && # a is moved instead of c
+	test_grep "^+f" diff &&
 
 	# with 2 anchors, c and f are not moved
 	test_expect_code 1 git diff --no-index --anchored=c --anchored=f pre post >diff &&
-	grep "^+a" diff &&
-	grep "^+d" diff # d is moved instead of f
+	test_grep "^+a" diff &&
+	test_grep "^+d" diff # d is moved instead of f
 '
 
 test_expect_success '--anchored with nonexistent line has no effect' '
@@ -37,7 +37,7 @@ test_expect_success '--anchored with nonexistent line has no effect' '
 	printf "c\na\nb\n" >post &&
 
 	test_expect_code 1 git diff --no-index --anchored=x pre post >diff &&
-	grep "^+c" diff
+	test_grep "^+c" diff
 '
 
 test_expect_success '--anchored with non-unique line has no effect' '
@@ -45,7 +45,7 @@ test_expect_success '--anchored with non-unique line has no effect' '
 	printf "c\na\nb\nc\nd\ne\n" >post &&
 
 	test_expect_code 1 git diff --no-index --anchored=c pre post >diff &&
-	grep "^+c" diff
+	test_grep "^+c" diff
 '
 
 test_expect_success 'diff still produced with impossible multiple --anchored' '
@@ -66,16 +66,16 @@ test_expect_success 'later algorithm arguments override earlier ones' '
 	printf "c\na\nb\n" >post &&
 
 	test_expect_code 1 git diff --no-index --patience --anchored=c pre post >diff &&
-	grep "^+a" diff &&
+	test_grep "^+a" diff &&
 
 	test_expect_code 1 git diff --no-index --anchored=c --patience pre post >diff &&
-	grep "^+c" diff &&
+	test_grep "^+c" diff &&
 
 	test_expect_code 1 git diff --no-index --histogram --anchored=c pre post >diff &&
-	grep "^+a" diff &&
+	test_grep "^+a" diff &&
 
 	test_expect_code 1 git diff --no-index --anchored=c --histogram pre post >diff &&
-	grep "^+c" diff
+	test_grep "^+c" diff
 '
 
 test_expect_success '--anchored works with other commands like "git show"' '
@@ -88,7 +88,7 @@ test_expect_success '--anchored works with other commands like "git show"' '
 
 	# with anchor, a is moved
 	git show --patience --anchored=c >diff &&
-	grep "^+a" diff
+	test_grep "^+a" diff
 '
 
 test_done
diff --git a/t/t4067-diff-partial-clone.sh b/t/t4067-diff-partial-clone.sh
index 30813109ac..142abdf74a 100755
--- a/t/t4067-diff-partial-clone.sh
+++ b/t/t4067-diff-partial-clone.sh
@@ -70,9 +70,9 @@ test_expect_success 'diff skips same-OID blobs' '
 
 	# Ensure that only a and another-a are fetched.
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff HEAD^ HEAD &&
-	grep "want $(cat hash-old-a)" trace &&
-	grep "want $(cat hash-new-a)" trace &&
-	! grep "want $(cat hash-b)" trace
+	test_grep "want $(cat hash-old-a)" trace &&
+	test_grep "want $(cat hash-new-a)" trace &&
+	test_grep ! "want $(cat hash-b)" trace
 '
 
 test_expect_success 'when fetching missing objects, diff skips GITLINKs' '
@@ -103,8 +103,8 @@ test_expect_success 'when fetching missing objects, diff skips GITLINKs' '
 	# Ensure that a and another-a are fetched, and check (by successful
 	# execution of the diff) that no invalid OIDs are sent.
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff HEAD^ HEAD &&
-	grep "want $(cat hash-old-a)" trace &&
-	grep "want $(cat hash-new-a)" trace
+	test_grep "want $(cat hash-old-a)" trace &&
+	test_grep "want $(cat hash-new-a)" trace
 '
 
 test_expect_success 'diff with rename detection batches blobs' '
@@ -127,7 +127,7 @@ test_expect_success 'diff with rename detection batches blobs' '
 	# Ensure that there is exactly 1 negotiation by checking that there is
 	# only 1 "done" line sent. ("done" marks the end of negotiation.)
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff --raw -M HEAD^ HEAD >out &&
-	grep ":100644 100644.*R[0-9][0-9][0-9].*b.*c" out &&
+	test_grep ":100644 100644.*R[0-9][0-9][0-9].*b.*c" out &&
 	grep "fetch> done" trace >done_lines &&
 	test_line_count = 1 done_lines
 '
diff --git a/t/t4073-diff-stat-name-width.sh b/t/t4073-diff-stat-name-width.sh
index ec5d3c3c1f..2412420645 100755
--- a/t/t4073-diff-stat-name-width.sh
+++ b/t/t4073-diff-stat-name-width.sh
@@ -21,41 +21,41 @@ test_expect_success 'setup' '
 
 test_expect_success 'test name-width long enough for filepath' '
 	git diff HEAD~1 HEAD --stat --stat-name-width=12 >out &&
-	grep "d你好/f再见 |" out &&
+	test_grep "d你好/f再见 |" out &&
 	git diff HEAD~1 HEAD --stat --stat-name-width=11 >out &&
-	grep "d你好/f再见 |" out
+	test_grep "d你好/f再见 |" out
 '
 
 test_expect_success 'test name-width not long enough for dir name' '
 	git diff HEAD~1 HEAD --stat --stat-name-width=10 >out &&
-	grep ".../f再见  |" out &&
+	test_grep ".../f再见  |" out &&
 	git diff HEAD~1 HEAD --stat --stat-name-width=9 >out &&
-	grep ".../f再见 |" out
+	test_grep ".../f再见 |" out
 '
 
 test_expect_success 'test name-width not long enough for slash' '
 	git diff HEAD~1 HEAD --stat --stat-name-width=8 >out &&
-	grep "...f再见 |" out
+	test_grep "...f再见 |" out
 '
 
 test_expect_success 'test name-width not long enough for file name' '
 	git diff HEAD~1 HEAD --stat --stat-name-width=7 >out &&
-	grep "...再见 |" out &&
+	test_grep "...再见 |" out &&
 	git diff HEAD~1 HEAD --stat --stat-name-width=6 >out &&
-	grep "...见  |" out &&
+	test_grep "...见  |" out &&
 	git diff HEAD~1 HEAD --stat --stat-name-width=5 >out &&
-	grep "...见 |" out &&
+	test_grep "...见 |" out &&
 	git diff HEAD~1 HEAD --stat --stat-name-width=4 >out &&
-	grep "...  |" out
+	test_grep "...  |" out
 '
 
 test_expect_success 'test name-width minimum length' '
 	git diff HEAD~1 HEAD --stat --stat-name-width=3 >out &&
-	grep "... |" out &&
+	test_grep "... |" out &&
 	git diff HEAD~1 HEAD --stat --stat-name-width=2 >out &&
-	grep "... |" out &&
+	test_grep "... |" out &&
 	git diff HEAD~1 HEAD --stat --stat-name-width=1 >out &&
-	grep "... |" out
+	test_grep "... |" out
 '
 
 test_done
diff --git a/t/t4103-apply-binary.sh b/t/t4103-apply-binary.sh
index f2d41e06bc..bdd4ccf9e3 100755
--- a/t/t4103-apply-binary.sh
+++ b/t/t4103-apply-binary.sh
@@ -181,7 +181,7 @@ test_expect_success PERL_TEST_HELPERS 'reject truncated binary diff' '
 	do_reset &&
 	test_must_fail git apply patch.trunc 2>err &&
 	line=$(awk "END { print NR + 1 }" patch.trunc) &&
-	grep "error: corrupt binary patch at patch.trunc:$line: " err
+	test_grep "error: corrupt binary patch at patch.trunc:$line: " err
 '
 
 test_expect_success 'reject unrecognized binary diff' '
diff --git a/t/t4120-apply-popt.sh b/t/t4120-apply-popt.sh
index c960fdf622..c7801aec2c 100755
--- a/t/t4120-apply-popt.sh
+++ b/t/t4120-apply-popt.sh
@@ -18,7 +18,7 @@ test_expect_success setup '
 	git mv sub süb &&
 	echo B >süb/file1 &&
 	git diff >patch.escaped &&
-	grep "[\]" patch.escaped &&
+	test_grep "[\]" patch.escaped &&
 	rm süb/file1 &&
 	rmdir süb
 '
diff --git a/t/t4124-apply-ws-rule.sh b/t/t4124-apply-ws-rule.sh
index 205d86d05e..4c487fb576 100755
--- a/t/t4124-apply-ws-rule.sh
+++ b/t/t4124-apply-ws-rule.sh
@@ -222,8 +222,8 @@ test_expect_success 'trailing whitespace & no newline at the end of file' '
 	>target &&
 	create_patch >patch-file &&
 	git apply --whitespace=fix patch-file &&
-	grep "newline$" target &&
-	grep "^$" target
+	test_grep "newline$" target &&
+	test_grep "^$" target
 '
 
 test_expect_success 'blank at EOF with --whitespace=fix (1)' '
@@ -287,7 +287,7 @@ test_expect_success 'blank at EOF with --whitespace=warn' '
 	git checkout one &&
 	git apply --whitespace=warn patch 2>error &&
 	test_cmp expect one &&
-	grep "new blank line at EOF" error
+	test_grep "new blank line at EOF" error
 '
 
 test_expect_success 'blank at EOF with --whitespace=error' '
@@ -300,7 +300,7 @@ test_expect_success 'blank at EOF with --whitespace=error' '
 	git checkout one &&
 	test_must_fail git apply --whitespace=error patch 2>error &&
 	test_cmp expect one &&
-	grep "new blank line at EOF" error
+	test_grep "new blank line at EOF" error
 '
 
 test_expect_success 'blank but not empty at EOF' '
@@ -313,7 +313,7 @@ test_expect_success 'blank but not empty at EOF' '
 	git checkout one &&
 	git apply --whitespace=warn patch 2>error &&
 	test_cmp expect one &&
-	grep "new blank line at EOF" error
+	test_grep "new blank line at EOF" error
 '
 
 test_expect_success 'applying beyond EOF requires one non-blank context line' '
diff --git a/t/t4128-apply-root.sh b/t/t4128-apply-root.sh
index 5eba15fa66..c772faea62 100755
--- a/t/t4128-apply-root.sh
+++ b/t/t4128-apply-root.sh
@@ -138,7 +138,7 @@ test_expect_success 'apply --directory (delete file)' '
 	git add some/sub/dir/delfile &&
 	git apply --directory=some/sub/dir/ --index patch &&
 	git ls-files >out &&
-	! grep delfile out
+	test_grep ! delfile out
 '
 
 cat > patch << 'EOF'
diff --git a/t/t4140-apply-ita.sh b/t/t4140-apply-ita.sh
index 0b11a8aef4..49ebb51564 100755
--- a/t/t4140-apply-ita.sh
+++ b/t/t4140-apply-ita.sh
@@ -14,11 +14,11 @@ test_expect_success setup '
 	cat blueprint >test-file &&
 	git add -N test-file &&
 	git diff >creation-patch &&
-	grep "new file mode 100644" creation-patch &&
+	test_grep "new file mode 100644" creation-patch &&
 
 	rm -f test-file &&
 	git diff >deletion-patch &&
-	grep "deleted file mode 100644" deletion-patch &&
+	test_grep "deleted file mode 100644" deletion-patch &&
 
 	git rm -f test-file &&
 	test_write_lines 6 >>committed-file &&
diff --git a/t/t4141-apply-too-large.sh b/t/t4141-apply-too-large.sh
index eac6f7e151..b114a7adf7 100755
--- a/t/t4141-apply-too-large.sh
+++ b/t/t4141-apply-too-large.sh
@@ -16,7 +16,7 @@ test_expect_success EXPENSIVE 'git apply rejects patches that are too large' '
 		EOF
 		test-tool genzeros
 	} | test_copy_bytes $sz | test_must_fail git apply 2>err &&
-	grep "patch too large" err
+	test_grep "patch too large" err
 '
 
 test_done
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 699a81ab5c..61c3ce9018 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -580,7 +580,7 @@ test_expect_success 'am --keep really keeps the subject' '
 	git am --keep patch4 &&
 	test_path_is_missing .git/rebase-apply &&
 	git cat-file commit HEAD >actual &&
-	grep "Re: Re: Re: \[PATCH 1/5 v2\] \[foo\] third" actual
+	test_grep "Re: Re: Re: \[PATCH 1/5 v2\] \[foo\] third" actual
 '
 
 test_expect_success 'am --keep-non-patch really keeps the non-patch part' '
@@ -590,7 +590,7 @@ test_expect_success 'am --keep-non-patch really keeps the non-patch part' '
 	git am --keep-non-patch patch4 &&
 	test_path_is_missing .git/rebase-apply &&
 	git cat-file commit HEAD >actual &&
-	grep "^\[foo\] third" actual
+	test_grep "^\[foo\] third" actual
 '
 
 test_expect_success 'setup am -3' '
@@ -642,7 +642,7 @@ test_expect_success 'am with config am.threeWay overridden by --no-3way' '
 '
 
 test_expect_success 'am can rename a file' '
-	grep "^rename from" rename.patch &&
+	test_grep "^rename from" rename.patch &&
 	rm -fr .git/rebase-apply &&
 	git reset --hard &&
 	git checkout lorem^0 &&
@@ -653,7 +653,7 @@ test_expect_success 'am can rename a file' '
 '
 
 test_expect_success 'am -3 can rename a file' '
-	grep "^rename from" rename.patch &&
+	test_grep "^rename from" rename.patch &&
 	rm -fr .git/rebase-apply &&
 	git reset --hard &&
 	git checkout lorem^0 &&
@@ -664,7 +664,7 @@ test_expect_success 'am -3 can rename a file' '
 '
 
 test_expect_success 'am -3 can rename a file after falling back to 3-way merge' '
-	grep "^rename from" rename-add.patch &&
+	test_grep "^rename from" rename-add.patch &&
 	rm -fr .git/rebase-apply &&
 	git reset --hard &&
 	git checkout lorem^0 &&
@@ -884,7 +884,7 @@ test_expect_success 'am --ignore-date' '
 	git am --ignore-date patch1 &&
 	git cat-file commit HEAD | sed -e "/^\$/q" >head1 &&
 	sed -ne "/^author /s/.*> //p" head1 >at &&
-	grep "+0000" at
+	test_grep "+0000" at
 '
 
 test_expect_success 'am into an unborn branch' '
@@ -1066,7 +1066,7 @@ test_expect_success 'am --patch-format=mboxrd handles mboxrd' '
 	INPUT_END
 	git commit -F msg &&
 	git -c format.mboxrd format-patch --stdout -1 >mboxrd1 &&
-	grep "^>From could trip up a loose mbox parser" mboxrd1 &&
+	test_grep "^>From could trip up a loose mbox parser" mboxrd1 &&
 	git checkout -f first &&
 	git am --patch-format=mboxrd mboxrd1 &&
 	git cat-file commit HEAD | tail -n4 >out &&
@@ -1144,21 +1144,21 @@ test_expect_success 'am and .gitattibutes' '
 		git format-patch --stdout main..HEAD >patches &&
 		git reset --hard main &&
 		git am patches &&
-		grep "smudged" a.txt &&
+		test_grep "smudged" a.txt &&
 
 		git checkout removal &&
 		git reset --hard &&
 		git format-patch --stdout main..HEAD >patches &&
 		git reset --hard main &&
 		git am patches &&
-		grep "clean" a.txt &&
+		test_grep "clean" a.txt &&
 
 		git checkout conflict &&
 		git reset --hard &&
 		git format-patch --stdout main..HEAD >patches &&
 		git reset --hard fourth &&
 		test_must_fail git am -3 patches &&
-		grep "<<<<<<<<<<" a.txt
+		test_grep "<<<<<<<<<<" a.txt
 	)
 '
 
@@ -1196,13 +1196,13 @@ test_expect_success 'invalid when passing the --empty option alone' '
 test_expect_success 'a message without a patch is an error (default)' '
 	test_when_finished "git am --abort || :" &&
 	test_must_fail git am empty-commit.patch >err &&
-	grep "Patch is empty" err
+	test_grep "Patch is empty" err
 '
 
 test_expect_success 'a message without a patch is an error where an explicit "--empty=stop" is given' '
 	test_when_finished "git am --abort || :" &&
 	test_must_fail git am --empty=stop empty-commit.patch >err &&
-	grep "Patch is empty." err
+	test_grep "Patch is empty." err
 '
 
 test_expect_success 'a message without a patch will be skipped when "--empty=drop" is given' '
@@ -1210,7 +1210,7 @@ test_expect_success 'a message without a patch will be skipped when "--empty=dro
 	git rev-parse empty-commit^ >expected &&
 	git rev-parse HEAD >actual &&
 	test_cmp expected actual &&
-	grep "Skipping: empty commit" output
+	test_grep "Skipping: empty commit" output
 '
 
 test_expect_success 'record as an empty commit when meeting e-mail message that lacks a patch' '
@@ -1218,15 +1218,15 @@ test_expect_success 'record as an empty commit when meeting e-mail message that
 	test_path_is_missing .git/rebase-apply &&
 	git show empty-commit --format="%B" >expected &&
 	git show HEAD --format="%B" >actual &&
-	grep -f actual expected &&
-	grep "Creating an empty commit: empty commit" output
+	test_grep -f actual expected &&
+	test_grep "Creating an empty commit: empty commit" output
 '
 
 test_expect_success 'skip an empty patch in the middle of an am session' '
 	git checkout empty-commit^ &&
 	test_must_fail git am empty-commit.patch >out 2>err &&
-	grep "Patch is empty." out &&
-	grep "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
+	test_grep "Patch is empty." out &&
+	test_grep "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
 	git am --skip &&
 	test_path_is_missing .git/rebase-apply &&
 	git rev-parse empty-commit^ >expected &&
@@ -1237,14 +1237,14 @@ test_expect_success 'skip an empty patch in the middle of an am session' '
 test_expect_success 'record an empty patch as an empty commit in the middle of an am session' '
 	git checkout empty-commit^ &&
 	test_must_fail git am empty-commit.patch >out 2>err &&
-	grep "Patch is empty." out &&
-	grep "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
+	test_grep "Patch is empty." out &&
+	test_grep "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
 	git am --allow-empty >output &&
-	grep "No changes - recorded it as an empty commit." output &&
+	test_grep "No changes - recorded it as an empty commit." output &&
 	test_path_is_missing .git/rebase-apply &&
 	git show empty-commit --format="%B" >expected &&
 	git show HEAD --format="%B" >actual &&
-	grep -f actual expected
+	test_grep -f actual expected
 '
 
 test_expect_success 'create an non-empty commit when the index IS changed though "--allow-empty" is given' '
@@ -1255,7 +1255,7 @@ test_expect_success 'create an non-empty commit when the index IS changed though
 	git am --allow-empty &&
 	git show empty-commit --format="%B" >expected &&
 	git show HEAD --format="%B" >actual &&
-	grep -f actual expected &&
+	test_grep -f actual expected &&
 	git diff HEAD^..HEAD --name-only
 '
 
@@ -1264,7 +1264,7 @@ test_expect_success 'cannot create empty commits when there is a clean index due
 	git rev-parse HEAD >expected &&
 	test_must_fail git am seq.patch &&
 	test_must_fail git am --allow-empty >err &&
-	! grep "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
+	test_grep ! "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
 	git rev-parse HEAD >actual &&
 	test_cmp actual expected
 '
@@ -1274,7 +1274,7 @@ test_expect_success 'cannot create empty commits when there is unmerged index du
 	git rev-parse HEAD >expected &&
 	test_must_fail git am -3 seq.patch &&
 	test_must_fail git am --allow-empty >err &&
-	! grep "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
+	test_grep ! "To record the empty patch as an empty commit, run \"git am --allow-empty\"." err &&
 	git rev-parse HEAD >actual &&
 	test_cmp actual expected
 '
diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index 1717f407c8..5466fb78bc 100755
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -83,7 +83,7 @@ test_expect_success 'activate rerere, old style (conflicting merge)' '
 
 	sha1=$(sed "s/	.*//" .git/MERGE_RR) &&
 	rr=.git/rr-cache/$sha1 &&
-	grep "^=======\$" $rr/preimage &&
+	test_grep "^=======\$" $rr/preimage &&
 	test_path_is_missing $rr/postimage &&
 	test_path_is_missing $rr/thisimage
 '
@@ -96,7 +96,7 @@ test_expect_success 'rerere.enabled works, too' '
 
 	sha1=$(sed "s/	.*//" .git/MERGE_RR) &&
 	rr=.git/rr-cache/$sha1 &&
-	grep ^=======$ $rr/preimage
+	test_grep ^=======$ $rr/preimage
 '
 
 test_expect_success 'set up rr-cache' '
@@ -177,7 +177,7 @@ test_expect_success 'first postimage wins' '
 
 	test_must_fail git merge first &&
 	# rerere kicked in
-	! grep "^=======\$" a1 &&
+	test_grep ! "^=======\$" a1 &&
 	test_cmp expect a1
 '
 
diff --git a/t/t4201-shortlog.sh b/t/t4201-shortlog.sh
index 9f41d56d9a..023fbff546 100755
--- a/t/t4201-shortlog.sh
+++ b/t/t4201-shortlog.sh
@@ -267,7 +267,7 @@ test_expect_success 'shortlog --group=<format> DWIM' '
 
 test_expect_success 'shortlog bogus --group' '
 	test_must_fail git shortlog --group=bogus HEAD 2>err &&
-	grep "unknown group type" err
+	test_grep "unknown group type" err
 '
 
 test_expect_success 'trailer idents are split' '
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 05cee9e41b..6dc134fa8e 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -668,12 +668,12 @@ test_expect_success 'log --graph with merge with log.graphColors' '
 
 test_expect_success 'log --raw --graph -m with merge' '
 	git log --raw --graph --oneline -m main | head -n 500 >actual &&
-	grep "initial" actual
+	test_grep "initial" actual
 '
 
 test_expect_success 'diff-tree --graph' '
 	git diff-tree --graph main^ | head -n 500 >actual &&
-	grep "one" actual
+	test_grep "one" actual
 '
 
 cat > expect <<\EOF
@@ -1082,13 +1082,13 @@ test_expect_success 'decorate-refs and simplify-by-decoration without output' '
 test_expect_success 'decorate-refs-exclude HEAD' '
 	git log --decorate=full --oneline \
 		--decorate-refs-exclude="HEAD" >actual &&
-	! grep HEAD actual
+	test_grep ! HEAD actual
 '
 
 test_expect_success 'decorate-refs focus from default' '
 	git log --decorate=full --oneline \
 		--decorate-refs="refs/heads" >actual &&
-	! grep HEAD actual
+	test_grep ! HEAD actual
 '
 
 test_expect_success '--clear-decorations overrides defaults' '
@@ -2055,45 +2055,45 @@ test_expect_success GPGSSH 'log ssh key fingerprint' '
 
 test_expect_success GPG 'log --graph --show-signature' '
 	git log --graph --show-signature -n1 signed >actual &&
-	grep "^| gpg: Signature made" actual &&
-	grep "^| gpg: Good signature" actual
+	test_grep "^| gpg: Signature made" actual &&
+	test_grep "^| gpg: Good signature" actual
 '
 
 test_expect_success GPGSM 'log --graph --show-signature x509' '
 	git log --graph --show-signature -n1 signed-x509 >actual &&
-	grep "^| gpgsm: Signature made" actual &&
-	grep "^| gpgsm: Good signature" actual
+	test_grep "^| gpgsm: Signature made" actual &&
+	test_grep "^| gpgsm: Good signature" actual
 '
 
 test_expect_success GPGSSH 'log --graph --show-signature ssh' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git log --graph --show-signature -n1 signed-ssh >actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'log shows failure on expired signature key' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git log --graph --show-signature -n1 expired-signed >actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'log shows failure on not yet valid signature key' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git log --graph --show-signature -n1 notyetvalid-signed >actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'log show success with commit date and key validity matching' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git log --graph --show-signature -n1 timeboxedvalid-signed >actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'log shows failure with commit date outside of key validity' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git log --graph --show-signature -n1 timeboxedinvalid-signed >actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPG 'log --graph --show-signature for merged tag' '
@@ -2110,9 +2110,9 @@ test_expect_success GPG 'log --graph --show-signature for merged tag' '
 	git checkout plain &&
 	git merge --no-ff -m msg signed_tag &&
 	git log --graph --show-signature -n1 plain >actual &&
-	grep "^|\\\  merged tag" actual &&
-	grep "^| | gpg: Signature made" actual &&
-	grep "^| | gpg: Good signature" actual
+	test_grep "^|\\\  merged tag" actual &&
+	test_grep "^| | gpg: Signature made" actual &&
+	test_grep "^| | gpg: Good signature" actual
 '
 
 test_expect_success GPG 'log --graph --show-signature for merged tag in shallow clone' '
@@ -2132,7 +2132,7 @@ test_expect_success GPG 'log --graph --show-signature for merged tag in shallow
 	git clone --depth 1 --no-local . shallow &&
 	test_when_finished "rm -rf shallow" &&
 	git -C shallow log --graph --show-signature -n1 plain-shallow >actual &&
-	grep "tag signed_tag_shallow names a non-parent $hash" actual
+	test_grep "tag signed_tag_shallow names a non-parent $hash" actual
 '
 
 test_expect_success GPG 'log --graph --show-signature for merged tag with missing key' '
@@ -2149,9 +2149,9 @@ test_expect_success GPG 'log --graph --show-signature for merged tag with missin
 	git checkout plain-nokey &&
 	git merge --no-ff -m msg signed_tag_nokey &&
 	GNUPGHOME=. git log --graph --show-signature -n1 plain-nokey >actual &&
-	grep "^|\\\  merged tag" actual &&
-	grep "^| | gpg: Signature made" actual &&
-	grep -E "^| | gpg: Can'"'"'t check signature: (public key not found|No public key)" actual
+	test_grep "^|\\\  merged tag" actual &&
+	test_grep "^| | gpg: Signature made" actual &&
+	test_grep -E "^| | gpg: Can'"'"'t check signature: (public key not found|No public key)" actual
 '
 
 test_expect_success GPG 'log --graph --show-signature for merged tag with bad signature' '
@@ -2171,9 +2171,9 @@ test_expect_success GPG 'log --graph --show-signature for merged tag with bad si
 	git checkout plain-bad &&
 	git merge --no-ff -m msg "$(cat forged.tag)" &&
 	git log --graph --show-signature -n1 plain-bad >actual &&
-	grep "^|\\\  merged tag" actual &&
-	grep "^| | gpg: Signature made" actual &&
-	grep "^| | gpg: BAD signature from" actual
+	test_grep "^|\\\  merged tag" actual &&
+	test_grep "^| | gpg: Signature made" actual &&
+	test_grep "^| | gpg: BAD signature from" actual
 '
 
 test_expect_success GPG 'log --show-signature for merged tag with GPG failure' '
@@ -2192,9 +2192,9 @@ test_expect_success GPG 'log --show-signature for merged tag with GPG failure' '
 	if ! test_have_prereq VALGRIND
 	then
 		TMPDIR="$(pwd)/bogus" git log --show-signature -n1 plain-fail >actual &&
-		grep "^merged tag" actual &&
-		grep "^No signature" actual &&
-		! grep "^gpg: Signature made" actual
+		test_grep "^merged tag" actual &&
+		test_grep "^No signature" actual &&
+		test_grep ! "^gpg: Signature made" actual
 	fi
 '
 
@@ -2214,9 +2214,9 @@ test_expect_success GPGSM 'log --graph --show-signature for merged tag x509' '
 	git checkout plain-x509 &&
 	git merge --no-ff -m msg signed_tag_x509 &&
 	git log --graph --show-signature -n1 plain-x509 >actual &&
-	grep "^|\\\  merged tag" actual &&
-	grep "^| | gpgsm: Signature made" actual &&
-	grep "^| | gpgsm: Good signature" actual
+	test_grep "^|\\\  merged tag" actual &&
+	test_grep "^| | gpgsm: Signature made" actual &&
+	test_grep "^| | gpgsm: Good signature" actual
 '
 
 test_expect_success GPGSM 'log --graph --show-signature for merged tag x509 missing key' '
@@ -2235,8 +2235,8 @@ test_expect_success GPGSM 'log --graph --show-signature for merged tag x509 miss
 	git checkout plain-x509-nokey &&
 	git merge --no-ff -m msg signed_tag_x509_nokey &&
 	GNUPGHOME=. git log --graph --show-signature -n1 plain-x509-nokey >actual &&
-	grep "^|\\\  merged tag" actual &&
-	grep -e "^| | gpgsm: certificate not found" \
+	test_grep "^|\\\  merged tag" actual &&
+	test_grep -e "^| | gpgsm: certificate not found" \
 	     -e "^| | gpgsm: failed to find the certificate: Not found" actual
 '
 
@@ -2259,35 +2259,35 @@ test_expect_success GPGSM 'log --graph --show-signature for merged tag x509 bad
 	git checkout plain-x509-bad &&
 	git merge --no-ff -m msg "$(cat forged.tag)" &&
 	git log --graph --show-signature -n1 plain-x509-bad >actual &&
-	grep "^|\\\  merged tag" actual &&
-	grep "^| | gpgsm: Signature made" actual &&
-	grep "^| | gpgsm: invalid signature" actual
+	test_grep "^|\\\  merged tag" actual &&
+	test_grep "^| | gpgsm: Signature made" actual &&
+	test_grep "^| | gpgsm: invalid signature" actual
 '
 
 
 test_expect_success GPG '--no-show-signature overrides --show-signature' '
 	git log -1 --show-signature --no-show-signature signed >actual &&
-	! grep "^gpg:" actual
+	test_grep ! "^gpg:" actual
 '
 
 test_expect_success GPG 'log.showsignature=true behaves like --show-signature' '
 	test_config log.showsignature true &&
 	git log -1 signed >actual &&
-	grep "gpg: Signature made" actual &&
-	grep "gpg: Good signature" actual
+	test_grep "gpg: Signature made" actual &&
+	test_grep "gpg: Good signature" actual
 '
 
 test_expect_success GPG '--no-show-signature overrides log.showsignature=true' '
 	test_config log.showsignature true &&
 	git log -1 --no-show-signature signed >actual &&
-	! grep "^gpg:" actual
+	test_grep ! "^gpg:" actual
 '
 
 test_expect_success GPG '--show-signature overrides log.showsignature=false' '
 	test_config log.showsignature false &&
 	git log -1 --show-signature signed >actual &&
-	grep "gpg: Signature made" actual &&
-	grep "gpg: Good signature" actual
+	test_grep "gpg: Signature made" actual &&
+	test_grep "gpg: Good signature" actual
 '
 
 test_expect_success 'log --graph --no-walk is forbidden' '
@@ -2383,7 +2383,7 @@ test_expect_success 'log --decorate does not include things outside filter' '
 	git log --decorate=full --oneline >actual &&
 
 	# None of the refs are visible:
-	! grep /fake actual
+	test_grep ! /fake actual
 '
 
 test_expect_success 'log --end-of-options' '
diff --git a/t/t4204-patch-id.sh b/t/t4204-patch-id.sh
index 605faea0c7..90e661fe98 100755
--- a/t/t4204-patch-id.sh
+++ b/t/t4204-patch-id.sh
@@ -44,7 +44,7 @@ test_expect_success 'setup' '
 test_expect_success 'patch-id output is well-formed' '
 	git log -p -1 >log.output &&
 	git patch-id <log.output >output &&
-	grep "^$OID_REGEX $(git rev-parse HEAD)$" output
+	test_grep "^$OID_REGEX $(git rev-parse HEAD)$" output
 '
 
 #calculate patch id. Make sure output is not empty.
diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh
index 3865f6abc7..4be5c51489 100755
--- a/t/t4205-log-pretty-formats.sh
+++ b/t/t4205-log-pretty-formats.sh
@@ -535,7 +535,7 @@ test_expect_success 'strbuf_utf8_replace() not producing NUL' '
 	git log --color --pretty="tformat:%<(10,trunc)%s%>>(10,ltrunc)%C(auto)%d" |
 		test_decode_color |
 		nul_to_q >actual &&
-	! grep Q actual
+	test_grep ! Q actual
 '
 
 # --date=[XXX] and corresponding %a[X] %c[X] format equivalency
diff --git a/t/t4209-log-pickaxe.sh b/t/t4209-log-pickaxe.sh
index 0e2f80a268..802597efc7 100755
--- a/t/t4209-log-pickaxe.sh
+++ b/t/t4209-log-pickaxe.sh
@@ -64,21 +64,21 @@ test_expect_success 'usage' '
 	test_grep "switch.*requires a value" err &&
 
 	test_expect_code 128 git log -Gregex -Sstring 2>err &&
-	grep "cannot be used together" err &&
+	test_grep "cannot be used together" err &&
 
 	test_expect_code 128 git log -Gregex --find-object=HEAD 2>err &&
-	grep "cannot be used together" err &&
+	test_grep "cannot be used together" err &&
 
 	test_expect_code 128 git log -Sstring --find-object=HEAD 2>err &&
-	grep "cannot be used together" err &&
+	test_grep "cannot be used together" err &&
 
 	test_expect_code 128 git log --pickaxe-all --find-object=HEAD 2>err &&
-	grep "cannot be used together" err
+	test_grep "cannot be used together" err
 '
 
 test_expect_success 'usage: --pickaxe-regex' '
 	test_expect_code 128 git log -Gregex --pickaxe-regex 2>err &&
-	grep "cannot be used together" err
+	test_grep "cannot be used together" err
 '
 
 test_expect_success 'usage: --no-pickaxe-regex' '
diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index aaf197d2ed..6cd80a92bb 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -356,14 +356,14 @@ test_expect_success '-L diff output includes index and new file mode' '
 	git log -L:func2:file.c --format= >actual &&
 
 	# Output should contain index headers (not present in old code path)
-	grep "^index $head_blob_old\.\.$head_blob_new 100644" actual &&
+	test_grep "^index $head_blob_old\.\.$head_blob_new 100644" actual &&
 
 	# Root commit should show new file mode and null index
-	grep "^new file mode 100644" actual &&
-	grep "^index $null_blob\.\.$root_blob$" actual &&
+	test_grep "^new file mode 100644" actual &&
+	test_grep "^index $null_blob\.\.$root_blob$" actual &&
 
 	# Hunk headers should include funcname context
-	grep "^@@ .* @@ int func1()" actual
+	test_grep "^@@ .* @@ int func1()" actual
 '
 
 test_expect_success '-L with --word-diff' '
@@ -396,15 +396,15 @@ test_expect_success '-L with --word-diff' '
 
 test_expect_success '-L with --no-prefix' '
 	git log -L:func2:file.c --no-prefix --format= >actual &&
-	grep "^diff --git file.c file.c" actual &&
-	grep "^--- file.c" actual &&
-	! grep "^--- a/" actual
+	test_grep "^diff --git file.c file.c" actual &&
+	test_grep "^--- file.c" actual &&
+	test_grep ! "^--- a/" actual
 '
 
 test_expect_success '-L with --full-index' '
 	git log -L:func2:file.c --full-index --format= >actual &&
-	grep "^index $head_blob_old_full\.\.$head_blob_new_full 100644" actual &&
-	grep "^index $null_blob_full\.\.$root_blob_full$" actual
+	test_grep "^index $head_blob_old_full\.\.$head_blob_new_full 100644" actual &&
+	test_grep "^index $null_blob_full\.\.$root_blob_full$" actual
 '
 
 test_expect_success 'setup -L with whitespace change' '
@@ -521,29 +521,29 @@ test_expect_success '-L with --word-diff-regex' '
 	git log -L:func2:file.c --word-diff \
 		--word-diff-regex="[a-zA-Z0-9_]+" --format= >actual &&
 	# Word-diff markers must be present
-	grep "{+" actual &&
-	grep "+}" actual &&
+	test_grep "{+" actual &&
+	test_grep "+}" actual &&
 	# No line-level +/- markers (word-diff replaces them);
 	# exclude --- header lines from the check
-	! grep "^+[^+]" actual &&
-	! grep "^-[^-]" actual
+	test_grep ! "^+[^+]" actual &&
+	test_grep ! "^-[^-]" actual
 '
 
 test_expect_success '-L with --src-prefix and --dst-prefix' '
 	git checkout parent-oids &&
 	git log -L:func2:file.c --src-prefix=old/ --dst-prefix=new/ \
 		--format= >actual &&
-	grep "^diff --git old/file.c new/file.c" actual &&
-	grep "^--- old/file.c" actual &&
-	grep "^+++ new/file.c" actual &&
-	! grep "^--- a/" actual
+	test_grep "^diff --git old/file.c new/file.c" actual &&
+	test_grep "^--- old/file.c" actual &&
+	test_grep "^+++ new/file.c" actual &&
+	test_grep ! "^--- a/" actual
 '
 
 test_expect_success '-L with --abbrev' '
 	git checkout parent-oids &&
 	git log -L:func2:file.c --abbrev=4 --format= -1 >actual &&
 	# 4-char abbreviated hashes on index line
-	grep "^index [0-9a-f]\{4\}\.\.[0-9a-f]\{4\}" actual
+	test_grep "^index [0-9a-f]\{4\}\.\.[0-9a-f]\{4\}" actual
 '
 
 test_expect_success '-L with -b suppresses whitespace-only diff' '
@@ -559,24 +559,24 @@ test_expect_success '-L with --output-indicator-*' '
 	git log -L:func2:file.c --output-indicator-new=">" \
 		--output-indicator-old="<" --output-indicator-context="|" \
 		--format= -1 >actual &&
-	grep "^>" actual &&
-	grep "^<" actual &&
-	grep "^|" actual &&
+	test_grep "^>" actual &&
+	test_grep "^<" actual &&
+	test_grep "^|" actual &&
 	# No standard +/-/space content markers; exclude ---/+++ headers
-	! grep "^+[^+]" actual &&
-	! grep "^-[^-]" actual &&
-	! grep "^ " actual
+	test_grep ! "^+[^+]" actual &&
+	test_grep ! "^-[^-]" actual &&
+	test_grep ! "^ " actual
 '
 
 test_expect_success '-L with -R reverses diff' '
 	git checkout parent-oids &&
 	git log -L:func2:file.c -R --format= -1 >actual &&
-	grep "^diff --git b/file.c a/file.c" actual &&
-	grep "^--- b/file.c" actual &&
-	grep "^+++ a/file.c" actual &&
+	test_grep "^diff --git b/file.c a/file.c" actual &&
+	test_grep "^--- b/file.c" actual &&
+	test_grep "^+++ a/file.c" actual &&
 	# The modification added "F2 + 2", so reversed it is removed
-	grep "^-.*F2 + 2" actual &&
-	grep "^+.*return F2;" actual
+	test_grep "^-.*F2 + 2" actual &&
+	test_grep "^+.*return F2;" actual
 '
 
 test_expect_success 'setup for color-moved test' '
@@ -602,8 +602,8 @@ test_expect_success '-L with --color-moved' '
 		--color=always --format= -1 >actual.raw &&
 	test_decode_color <actual.raw >actual &&
 	# Old moved lines: bold magenta; new moved lines: bold cyan
-	grep "BOLD;MAGENTA" actual &&
-	grep "BOLD;CYAN" actual
+	test_grep "BOLD;MAGENTA" actual &&
+	test_grep "BOLD;CYAN" actual
 '
 
 test_expect_success 'setup for no-newline-at-eof tests' '
@@ -623,14 +623,14 @@ test_expect_success 'setup for no-newline-at-eof tests' '
 # newline, the "\ No newline at end of file" marker should appear.
 test_expect_success '-L no-newline-at-eof appears in tracked range' '
 	git log -L:bot:noeol.c --format= -1 HEAD~1 >actual &&
-	grep "No newline at end of file" actual
+	test_grep "No newline at end of file" actual
 '
 
 # When tracking a function that ends before the no-newline content,
 # the marker should not appear in the output.
 test_expect_success '-L no-newline-at-eof suppressed outside range' '
 	git log -L:top:noeol.c --format= >actual &&
-	! grep "No newline at end of file" actual
+	test_grep ! "No newline at end of file" actual
 '
 
 # When a commit removes a no-newline last line and replaces it with
@@ -638,7 +638,7 @@ test_expect_success '-L no-newline-at-eof suppressed outside range' '
 # old side of the diff).
 test_expect_success '-L no-newline-at-eof marker with deleted line' '
 	git log -L:bot:noeol.c --format= -1 >actual &&
-	grep "No newline at end of file" actual
+	test_grep "No newline at end of file" actual
 '
 
 test_expect_success 'setup for range boundary deletion test' '
@@ -698,7 +698,7 @@ test_expect_success '-L with -S filters to string-count changes' '
 	# combined with the -L range walk, this selects commits that
 	# both touch func2 and change the count of "F2 + 2" in the file.
 	test $(grep -c "^diff --git" actual) = 1 &&
-	grep "F2 + 2" actual
+	test_grep "F2 + 2" actual
 '
 
 test_expect_success '-L with -G filters to diff-text matches' '
@@ -708,7 +708,7 @@ test_expect_success '-L with -G filters to diff-text matches' '
 	# combined with -L, this selects commits that both touch func2
 	# and have "F2 + 2" in their diff.
 	test $(grep -c "^diff --git" actual) = 1 &&
-	grep "F2 + 2" actual
+	test_grep "F2 + 2" actual
 '
 
 test_done
diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh
index 1064990de3..c66f25b932 100755
--- a/t/t4216-log-bloom.sh
+++ b/t/t4216-log-bloom.sh
@@ -224,10 +224,10 @@ test_expect_success 'persist filter settings' '
 		GIT_TEST_BLOOM_SETTINGS_NUM_HASHES=9 \
 		GIT_TEST_BLOOM_SETTINGS_BITS_PER_ENTRY=15 \
 		git commit-graph write --reachable --changed-paths &&
-	grep "{\"hash_version\":1,\"num_hashes\":9,\"bits_per_entry\":15,\"max_changed_paths\":512" trace2.txt &&
+	test_grep "{\"hash_version\":1,\"num_hashes\":9,\"bits_per_entry\":15,\"max_changed_paths\":512" trace2.txt &&
 	GIT_TRACE2_EVENT="$(pwd)/trace2-auto.txt" \
 		git commit-graph write --reachable --changed-paths &&
-	grep "{\"hash_version\":1,\"num_hashes\":9,\"bits_per_entry\":15,\"max_changed_paths\":512" trace2-auto.txt
+	test_grep "{\"hash_version\":1,\"num_hashes\":9,\"bits_per_entry\":15,\"max_changed_paths\":512" trace2-auto.txt
 '
 
 test_max_changed_paths () {
@@ -494,7 +494,7 @@ test_expect_success 'ensure Bloom filters with incompatible settings are ignored
 		>expect 2>err &&
 	git -C $repo log --oneline --no-decorate -- file >actual 2>err &&
 	test_cmp expect actual &&
-	grep "disabling Bloom filters for commit-graph layer .$layer." err
+	test_grep "disabling Bloom filters for commit-graph layer .$layer." err
 '
 
 test_expect_success 'merge graph layers with incompatible Bloom settings' '
@@ -503,8 +503,8 @@ test_expect_success 'merge graph layers with incompatible Bloom settings' '
 	>trace2.txt &&
 	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
 		git -C $repo commit-graph write --reachable --changed-paths 2>err &&
-	grep "disabling Bloom filters for commit-graph layer .$layer." err &&
-	grep "{\"hash_version\":1,\"num_hashes\":7,\"bits_per_entry\":10,\"max_changed_paths\":512" trace2.txt &&
+	test_grep "disabling Bloom filters for commit-graph layer .$layer." err &&
+	test_grep "{\"hash_version\":1,\"num_hashes\":7,\"bits_per_entry\":10,\"max_changed_paths\":512" trace2.txt &&
 
 	test_path_is_file $repo/$graph &&
 	test_dir_is_empty $repo/$graphdir &&
@@ -516,7 +516,7 @@ test_expect_success 'merge graph layers with incompatible Bloom settings' '
 		git -C $repo log --oneline --no-decorate -- file >actual 2>err &&
 
 	test_cmp expect actual &&
-	grep "statistics:{\"filter_not_present\":0," trace.perf &&
+	test_grep "statistics:{\"filter_not_present\":0," trace.perf &&
 	test_must_be_empty err
 '
 
@@ -554,8 +554,8 @@ test_expect_success 'ensure Bloom filter with incompatible versions are ignored'
 	>trace2.txt &&
 	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
 		git -C $repo -c commitGraph.changedPathsVersion=2 commit-graph write --reachable --changed-paths 2>err &&
-	grep "disabling Bloom filters for commit-graph layer .$layer." err &&
-	grep "{\"hash_version\":2,\"num_hashes\":7,\"bits_per_entry\":10,\"max_changed_paths\":512" trace2.txt
+	test_grep "disabling Bloom filters for commit-graph layer .$layer." err &&
+	test_grep "{\"hash_version\":2,\"num_hashes\":7,\"bits_per_entry\":10,\"max_changed_paths\":512" trace2.txt
 '
 
 get_first_changed_path_filter () {
@@ -776,7 +776,7 @@ test_expect_success PERL_TEST_HELPERS 'Bloom reader notices too-small data chunk
 test_expect_success PERL_TEST_HELPERS 'Bloom reader notices out-of-bounds filter offsets' '
 	check_corrupt_graph BIDX 12 FFFFFFFF &&
 	# use grep to avoid depending on exact chunk size
-	grep "warning: ignoring out-of-range offset (4294967295) for changed-path filter at pos 3 of .git/objects/info/commit-graph" err
+	test_grep "warning: ignoring out-of-range offset (4294967295) for changed-path filter at pos 3 of .git/objects/info/commit-graph" err
 '
 
 test_expect_success PERL_TEST_HELPERS 'Bloom reader notices too-small index chunk' '
diff --git a/t/t4252-am-options.sh b/t/t4252-am-options.sh
index bda8822b3d..c36c7e9017 100755
--- a/t/t4252-am-options.sh
+++ b/t/t4252-am-options.sh
@@ -20,8 +20,8 @@ test_expect_success 'interrupted am --whitespace=fix' '
 	git reset --hard initial &&
 	test_must_fail git am --whitespace=fix "$tm"/am-test-1-? &&
 	git am --skip &&
-	grep 3 file-1 &&
-	grep "^Six$" file-2
+	test_grep 3 file-1 &&
+	test_grep "^Six$" file-2
 '
 
 test_expect_success 'interrupted am -C1' '
@@ -29,8 +29,8 @@ test_expect_success 'interrupted am -C1' '
 	git reset --hard initial &&
 	test_must_fail git am -C1 "$tm"/am-test-2-? &&
 	git am --skip &&
-	grep 3 file-1 &&
-	grep "^Three$" file-2
+	test_grep 3 file-1 &&
+	test_grep "^Three$" file-2
 '
 
 test_expect_success 'interrupted am -p2' '
@@ -38,8 +38,8 @@ test_expect_success 'interrupted am -p2' '
 	git reset --hard initial &&
 	test_must_fail git am -p2 "$tm"/am-test-3-? &&
 	git am --skip &&
-	grep 3 file-1 &&
-	grep "^Three$" file-2
+	test_grep 3 file-1 &&
+	test_grep "^Three$" file-2
 '
 
 test_expect_success 'interrupted am -C1 -p2' '
@@ -47,8 +47,8 @@ test_expect_success 'interrupted am -C1 -p2' '
 	git reset --hard initial &&
 	test_must_fail git am -p2 -C1 "$tm"/am-test-4-? &&
 	git am --skip &&
-	grep 3 file-1 &&
-	grep "^Three$" file-2
+	test_grep 3 file-1 &&
+	test_grep "^Three$" file-2
 '
 
 test_expect_success 'interrupted am --directory="frotz nitfol"' '
@@ -56,7 +56,7 @@ test_expect_success 'interrupted am --directory="frotz nitfol"' '
 	git reset --hard initial &&
 	test_must_fail git am --directory="frotz nitfol" "$tm"/am-test-5-? &&
 	git am --skip &&
-	grep One "frotz nitfol/file-5"
+	test_grep One "frotz nitfol/file-5"
 '
 
 test_expect_success 'apply to a funny path' '
@@ -71,9 +71,9 @@ test_expect_success 'am --reject' '
 	rm -rf .git/rebase-apply &&
 	git reset --hard initial &&
 	test_must_fail git am --reject "$tm"/am-test-6-1 &&
-	grep "@@ -1,3 +1,3 @@" file-2.rej &&
+	test_grep "@@ -1,3 +1,3 @@" file-2.rej &&
 	test_must_fail git diff-files --exit-code --quiet file-2 &&
-	grep "[-]-reject" .git/rebase-apply/apply-opt
+	test_grep "[-]-reject" .git/rebase-apply/apply-opt
 '
 
 test_done
diff --git a/t/t4254-am-corrupt.sh b/t/t4254-am-corrupt.sh
index 96ddf3c53a..f68b5d3127 100755
--- a/t/t4254-am-corrupt.sh
+++ b/t/t4254-am-corrupt.sh
@@ -73,16 +73,16 @@ test_expect_success "NUL in commit message's body" '
 	test_when_finished "git am --abort" &&
 	make_mbox_with_nul body >body.patch &&
 	test_must_fail git am body.patch 2>err &&
-	grep "a NUL byte in commit log message not allowed" err
+	test_grep "a NUL byte in commit log message not allowed" err
 '
 
 test_expect_success "NUL in commit message's header" "
 	test_when_finished 'git am --abort' &&
 	make_mbox_with_nul subject >subject.patch &&
 	test_must_fail git mailinfo msg patch <subject.patch 2>err &&
-	grep \"a NUL byte in 'Subject' is not allowed\" err &&
+	test_grep \"a NUL byte in 'Subject' is not allowed\" err &&
 	test_must_fail git am subject.patch 2>err &&
-	grep \"a NUL byte in 'Subject' is not allowed\" err
+	test_grep \"a NUL byte in 'Subject' is not allowed\" err
 "
 
 test_done
diff --git a/t/t4258-am-quoted-cr.sh b/t/t4258-am-quoted-cr.sh
index 201915b45a..50e81b9330 100755
--- a/t/t4258-am-quoted-cr.sh
+++ b/t/t4258-am-quoted-cr.sh
@@ -16,7 +16,7 @@ test_expect_success 'setup' '
 test_expect_success 'am warn if quoted-cr is found' '
 	git reset --hard one &&
 	test_must_fail git am "$DATA/mbox" 2>err &&
-	grep "quoted CRLF detected" err
+	test_grep "quoted CRLF detected" err
 '
 
 test_expect_success 'am --quoted-cr=strip' '
diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 6e117ee93c..b2684911d1 100755
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -88,7 +88,7 @@ test_expect_success 'Clean merge' '
 # Repeat the previous test, but turn off rename detection
 test_expect_success 'Failed merge without rename detection' '
 	test_must_fail git -c diff.renames=false merge-tree --write-tree side1 side3 >out &&
-	grep "CONFLICT (modify/delete): numbers deleted" out
+	test_grep "CONFLICT (modify/delete): numbers deleted" out
 '
 
 test_expect_success  '--quiet on conflicted merge' '
@@ -161,13 +161,13 @@ test_expect_success 'Barf on misspelled option, with exit code other than 0 or 1
 	# Mis-spell with single "s" instead of double "s"
 	test_expect_code 129 git merge-tree --write-tree --mesages FOOBAR side1 side2 2>expect &&
 
-	grep "error: unknown option.*mesages" expect
+	test_grep "error: unknown option.*mesages" expect
 '
 
 test_expect_success 'Barf on too many arguments' '
 	test_expect_code 129 git merge-tree --write-tree side1 side2 invalid 2>expect &&
 
-	grep "^usage: git merge-tree" expect
+	test_grep "^usage: git merge-tree" expect
 '
 
 anonymize_hash() {
@@ -352,7 +352,7 @@ test_expect_success 'rename/add handling' '
 		#
 		hash=$(tr "\0" "\n" <out | head -n 3 | grep 3.bar | cut -f 2 -d " ") &&
 		git rev-list --objects --all >all_blobs &&
-		! grep $hash all_blobs &&
+		test_grep ! $hash all_blobs &&
 
 		#
 		# Second, check anonymized hash output against expectation
@@ -419,7 +419,7 @@ test_expect_success SYMLINKS 'rename/add, where add is a mode conflict' '
 		#
 		hash=$(tr "\0" "\n" <out | head -n 3 | grep 3.bar | cut -f 2 -d " ") &&
 		git rev-list --objects --all >all_blobs &&
-		! grep $hash all_blobs &&
+		test_grep ! $hash all_blobs &&
 
 		#
 		# Second, check anonymized hash output against expectation
@@ -670,8 +670,8 @@ test_expect_success 'mod6: chains of rename/rename(1to2) and add/add via collidi
 		hash1=$(tr "\0" "\n" <out | head | grep 2.four | cut -f 2 -d " ") &&
 		hash2=$(tr "\0" "\n" <out | head | grep 3.two | cut -f 2 -d " ") &&
 		git rev-list --objects --all >all_blobs &&
-		! grep $hash1 all_blobs &&
-		! grep $hash2 all_blobs &&
+		test_grep ! $hash1 all_blobs &&
+		test_grep ! $hash2 all_blobs &&
 
 		#
 		# Now compare anonymized hash output with expectation
@@ -857,7 +857,7 @@ test_expect_success 'NUL terminated conflicted file "lines"' '
 test_expect_success 'error out by default for unrelated histories' '
 	test_expect_code 128 git merge-tree --write-tree side1 unrelated 2>error &&
 
-	grep "refusing to merge unrelated histories" error
+	test_grep "refusing to merge unrelated histories" error
 '
 
 test_expect_success 'can override merge of unrelated histories' '
@@ -924,7 +924,7 @@ test_expect_success '--stdin with both a successful and a conflicted merge' '
 test_expect_success '--merge-base is incompatible with --stdin' '
 	test_must_fail git merge-tree --merge-base=side1 --stdin 2>expect &&
 
-	grep "^fatal: .*merge-base.*stdin.* cannot be used together" expect
+	test_grep "^fatal: .*merge-base.*stdin.* cannot be used together" expect
 '
 
 # specify merge-base as parent of branch2
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index a8c28533dc..3ad600c793 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -323,14 +323,14 @@ test_expect_success 'setup tar filters' '
 
 test_expect_success 'archive --list mentions user filter' '
 	git archive --list >output &&
-	grep "^tar\.foo\$" output &&
-	grep "^bar\$" output
+	test_grep "^tar\.foo\$" output &&
+	test_grep "^bar\$" output
 '
 
 test_expect_success 'archive --list shows only enabled remote filters' '
 	git archive --list --remote=. >output &&
-	! grep "^tar\.foo\$" output &&
-	grep "^bar\$" output
+	test_grep ! "^tar\.foo\$" output &&
+	test_grep "^bar\$" output
 '
 
 test_expect_success 'invoke tar filter by format' '
@@ -440,7 +440,7 @@ test_expect_success 'catch non-matching pathspec' '
 
 test_expect_success 'reject paths outside the current directory' '
 	test_must_fail git -C a/bin archive HEAD .. >/dev/null 2>err &&
-	grep "outside the current directory" err
+	test_grep "outside the current directory" err
 '
 
 test_expect_success 'allow pathspecs that resolve to the current directory' '
diff --git a/t/t5004-archive-corner-cases.sh b/t/t5004-archive-corner-cases.sh
index df513a4269..768b0ff85d 100755
--- a/t/t5004-archive-corner-cases.sh
+++ b/t/t5004-archive-corner-cases.sh
@@ -205,7 +205,7 @@ test_expect_success EXPENSIVE,LONG_IS_64BIT,UNZIP,UNZIP_ZIP64_SUPPORT,ZIPINFO \
 
 	"$GIT_UNZIP" -t big.zip &&
 	"$ZIPINFO" big.zip >big.lst &&
-	grep $size big.lst
+	test_grep $size big.lst
 '
 
 build_tree() {
diff --git a/t/t5100-mailinfo.sh b/t/t5100-mailinfo.sh
index e57e1ae739..e01078abe7 100755
--- a/t/t5100-mailinfo.sh
+++ b/t/t5100-mailinfo.sh
@@ -265,7 +265,7 @@ test_expect_success 'mailinfo warn CR in base64 encoded email' '
 	check_quoted_cr_mail quoted-cr/0001 &&
 	test_must_be_empty quoted-cr/0001.err &&
 	check_quoted_cr_mail quoted-cr/0002 &&
-	grep "quoted CRLF detected" quoted-cr/0002.err &&
+	test_grep "quoted CRLF detected" quoted-cr/0002.err &&
 	check_quoted_cr_mail quoted-cr/0001 --quoted-cr=nowarn &&
 	test_must_be_empty quoted-cr/0001.err &&
 	check_quoted_cr_mail quoted-cr/0002 --quoted-cr=nowarn &&
diff --git a/t/t5150-request-pull.sh b/t/t5150-request-pull.sh
index 270ce6ea48..67c5dc7e85 100755
--- a/t/t5150-request-pull.sh
+++ b/t/t5150-request-pull.sh
@@ -130,8 +130,8 @@ test_expect_success 'pull request when forgot to push' '
 		test_must_fail git request-pull initial "$downstream_url" \
 			2>../err
 	) &&
-	grep "No match for commit .*" err &&
-	grep "Are you sure you pushed" err
+	test_grep "No match for commit .*" err &&
+	test_grep "Are you sure you pushed" err
 
 '
 
@@ -230,7 +230,7 @@ test_expect_success 'pull request format' '
 		cd local &&
 		git request-pull initial "$downstream_url" full
 	) >request &&
-	grep " tags/full\$" request
+	test_grep " tags/full\$" request
 '
 
 test_expect_success 'request-pull ignores OPTIONS_KEEPDASHDASH poison' '
@@ -260,8 +260,8 @@ test_expect_success 'request-pull quotes regex metacharacters properly' '
 		test_must_fail git request-pull initial "$downstream_url" tags/v2.0 \
 			2>../err
 	) &&
-	grep "No match for commit .*" err &&
-	grep "Are you sure you pushed" err
+	test_grep "No match for commit .*" err &&
+	test_grep "Are you sure you pushed" err
 
 '
 
@@ -277,8 +277,8 @@ test_expect_success 'pull request with mismatched object' '
 		test_must_fail git request-pull initial "$downstream_url" tags/full \
 			2>../err
 	) &&
-	grep "points to a different object" err &&
-	grep "Are you sure you pushed" err
+	test_grep "points to a different object" err &&
+	test_grep "Are you sure you pushed" err
 
 '
 
@@ -295,8 +295,8 @@ test_expect_success 'pull request with stale object' '
 		test_must_fail git request-pull initial "$downstream_url" tags/full \
 			2>../err
 	) &&
-	grep "points to a different object" err &&
-	grep "Are you sure you pushed" err
+	test_grep "points to a different object" err &&
+	test_grep "Are you sure you pushed" err
 
 '
 
diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
index 3179b4963e..9dabb3615a 100755
--- a/t/t5300-pack-object.sh
+++ b/t/t5300-pack-object.sh
@@ -548,18 +548,18 @@ test_expect_success !PTHREADS,!FAIL_PREREQS \
 	test_must_fail git index-pack --threads=2 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 1 warnings &&
-	grep -F "no threads support, ignoring --threads=2" err &&
+	test_grep -F "no threads support, ignoring --threads=2" err &&
 
 	test_must_fail git -c pack.threads=2 index-pack 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 1 warnings &&
-	grep -F "no threads support, ignoring pack.threads" err &&
+	test_grep -F "no threads support, ignoring pack.threads" err &&
 
 	test_must_fail git -c pack.threads=2 index-pack --threads=4 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 2 warnings &&
-	grep -F "no threads support, ignoring --threads=4" err &&
-	grep -F "no threads support, ignoring pack.threads" err
+	test_grep -F "no threads support, ignoring --threads=4" err &&
+	test_grep -F "no threads support, ignoring pack.threads" err
 '
 
 test_expect_success !PTHREADS,!FAIL_PREREQS \
@@ -567,18 +567,18 @@ test_expect_success !PTHREADS,!FAIL_PREREQS \
 	git pack-objects --threads=2 --stdout --all </dev/null >/dev/null 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 1 warnings &&
-	grep -F "no threads support, ignoring --threads" err &&
+	test_grep -F "no threads support, ignoring --threads" err &&
 
 	git -c pack.threads=2 pack-objects --stdout --all </dev/null >/dev/null 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 1 warnings &&
-	grep -F "no threads support, ignoring pack.threads" err &&
+	test_grep -F "no threads support, ignoring pack.threads" err &&
 
 	git -c pack.threads=2 pack-objects --threads=4 --stdout --all </dev/null >/dev/null 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 2 warnings &&
-	grep -F "no threads support, ignoring --threads" err &&
-	grep -F "no threads support, ignoring pack.threads" err
+	test_grep -F "no threads support, ignoring --threads" err &&
+	test_grep -F "no threads support, ignoring pack.threads" err
 '
 
 test_expect_success 'pack-objects in too-many-packs mode' '
@@ -727,7 +727,7 @@ test_expect_success '--path-walk pack everything' '
 	git -C server rev-parse HEAD >in &&
 	GIT_PROGRESS_DELAY=0 git -C server pack-objects \
 		--stdout --revs --path-walk --progress <in >out.pack 2>err &&
-	grep "Compressing objects by path" err &&
+	test_grep "Compressing objects by path" err &&
 	git -C server index-pack --stdin <out.pack
 '
 
@@ -738,7 +738,7 @@ test_expect_success '--path-walk thin pack' '
 	EOF
 	GIT_PROGRESS_DELAY=0 git -C server pack-objects \
 		--thin --stdout --revs --path-walk --progress <in >out.pack 2>err &&
-	grep "Compressing objects by path" err &&
+	test_grep "Compressing objects by path" err &&
 	git -C server index-pack --fix-thin --stdin <out.pack
 '
 
diff --git a/t/t5302-pack-index.sh b/t/t5302-pack-index.sh
index 9697448cb2..735de1023e 100755
--- a/t/t5302-pack-index.sh
+++ b/t/t5302-pack-index.sh
@@ -270,12 +270,12 @@ EOF
 	thirtyeight=${tag#??} &&
 	rm -f .git/objects/${tag%$thirtyeight}/$thirtyeight &&
 	git index-pack --strict tag-test-${pack1}.pack 2>err &&
-	grep "^warning:.* expected .tagger. line" err
+	test_grep "^warning:.* expected .tagger. line" err
 '
 
 test_expect_success 'index-pack --fsck-objects also warns upon missing tagger in tag' '
 	git index-pack --fsck-objects tag-test-${pack1}.pack 2>err &&
-	grep "^warning:.* expected .tagger. line" err
+	test_grep "^warning:.* expected .tagger. line" err
 '
 
 test_expect_success 'index-pack -v --stdin produces progress for both phases' '
@@ -290,7 +290,7 @@ test_expect_success 'too-large packs report the breach' '
 	sz="$(test_file_size pack-$pack.pack)" &&
 	test "$sz" -gt 20 &&
 	test_must_fail git index-pack --max-input-size=20 pack-$pack.pack 2>err &&
-	grep "maximum allowed size (20 bytes)" err
+	test_grep "maximum allowed size (20 bytes)" err
 '
 
 # git-index-pack(1) uses the default hash algorithm outside of the repository,
diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
index 2be7cd30de..db8e389c2c 100755
--- a/t/t5304-prune.sh
+++ b/t/t5304-prune.sh
@@ -120,7 +120,7 @@ test_expect_success 'prune: prune former HEAD after checking out branch' '
 	git checkout --quiet main &&
 	git reflog expire --all &&
 	git prune -v >prune_actual &&
-	grep "$head_oid" prune_actual
+	test_grep "$head_oid" prune_actual
 '
 
 test_expect_success 'prune: do not prune heads listed as an argument' '
@@ -214,7 +214,7 @@ test_expect_success 'garbage report in count-objects -v' '
 	>.git/objects/pack/fake2.keep &&
 	>.git/objects/pack/fake3.idx &&
 	git count-objects -v 2>stderr &&
-	grep "index file .git/objects/pack/fake.idx is too small" stderr &&
+	test_grep "index file .git/objects/pack/fake.idx is too small" stderr &&
 	grep "^warning:" stderr | sort >actual &&
 	cat >expected <<\EOF &&
 warning: garbage found: .git/objects/pack/fake.bar
@@ -252,8 +252,8 @@ test_expect_success 'prune .git/shallow' '
 	oid=$(echo hi|git commit-tree HEAD^{tree}) &&
 	echo $oid >.git/shallow &&
 	git prune --dry-run >out &&
-	grep $oid .git/shallow &&
-	grep $oid out &&
+	test_grep $oid .git/shallow &&
+	test_grep $oid out &&
 	git prune &&
 	test_path_is_missing .git/shallow
 '
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index efeb71593b..33ccb579c5 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -81,8 +81,8 @@ test_bitmap_cases () {
 			git repack -ad &&
 		ls .git/objects/pack/ | grep bitmap >output &&
 		test_line_count = 1 output &&
-		grep "\"key\":\"num_selected_commits\",\"value\":\"106\"" trace &&
-		grep "\"key\":\"num_maximal_commits\",\"value\":\"107\"" trace
+		test_grep "\"key\":\"num_selected_commits\",\"value\":\"106\"" trace &&
+		test_grep "\"key\":\"num_maximal_commits\",\"value\":\"107\"" trace
 	'
 
 	basic_bitmap_tests
@@ -532,8 +532,8 @@ test_bitmap_cases () {
 			test_line_count = 2 bitmaps &&
 
 			GIT_TRACE2_EVENT=$(pwd)/trace2.txt git rev-list --use-bitmap-index HEAD &&
-			grep "opened bitmap" trace2.txt &&
-			grep "ignoring extra bitmap" trace2.txt
+			test_grep "opened bitmap" trace2.txt &&
+			test_grep "ignoring extra bitmap" trace2.txt
 		)
 	'
 
@@ -598,7 +598,7 @@ test_expect_success 'boundary-based traversal is used when requested' '
 	do
 		eval "GIT_TRACE2_EVENT=1 $argv rev-list --objects \
 			--use-bitmap-index second..other 2>perf" &&
-		grep "\"region_enter\".*\"label\":\"haves/boundary\"" perf ||
+		test_grep "\"region_enter\".*\"label\":\"haves/boundary\"" perf ||
 			return 1
 	done &&
 
@@ -610,7 +610,7 @@ test_expect_success 'boundary-based traversal is used when requested' '
 	do
 		eval "GIT_TRACE2_EVENT=1 $argv rev-list --objects \
 			--use-bitmap-index second..other 2>perf" &&
-		grep "\"region_enter\".*\"label\":\"haves/classic\"" perf ||
+		test_grep "\"region_enter\".*\"label\":\"haves/classic\"" perf ||
 			return 1
 	done
 '
@@ -632,7 +632,7 @@ test_bitmap_cases "pack.writeBitmapLookupTable"
 test_expect_success 'verify writing bitmap lookup table when enabled' '
 	GIT_TRACE2_EVENT="$(pwd)/trace2" \
 		git repack -ad &&
-	grep "\"label\":\"writing_lookup_table\"" trace2
+	test_grep "\"label\":\"writing_lookup_table\"" trace2
 '
 
 test_expect_success 'truncated bitmap fails gracefully (lookup table)' '
diff --git a/t/t5317-pack-objects-filter-objects.sh b/t/t5317-pack-objects-filter-objects.sh
index dddb79ba62..2948a7cd2a 100755
--- a/t/t5317-pack-objects-filter-objects.sh
+++ b/t/t5317-pack-objects-filter-objects.sh
@@ -49,7 +49,7 @@ test_expect_success 'verify blob:none packfile has no blobs' '
 	git -C r1 index-pack ../filter.pack &&
 
 	git -C r1 verify-pack -v ../filter.pack >verify_result &&
-	! grep blob verify_result
+	test_grep ! blob verify_result
 '
 
 test_expect_success 'verify blob:none packfile without --stdout' '
@@ -57,7 +57,7 @@ test_expect_success 'verify blob:none packfile without --stdout' '
 	HEAD
 	EOF
 	git -C r1 verify-pack -v "mypackname-$(cat packhash).pack" >verify_result &&
-	! grep blob verify_result
+	test_grep ! blob verify_result
 '
 
 test_expect_success 'verify normal and blob:none packfiles have same commits/trees' '
@@ -85,7 +85,7 @@ test_expect_success 'get an error for missing tree object' '
 	test_must_fail git -C r5 pack-objects --revs --stdout 2>bad_tree <<-EOF &&
 	HEAD
 	EOF
-	grep "bad tree object" bad_tree
+	test_grep "bad tree object" bad_tree
 '
 
 test_expect_success 'setup for tests of tree:0' '
@@ -101,7 +101,7 @@ test_expect_success 'verify tree:0 packfile has no blobs or trees' '
 	EOF
 	git -C r1 index-pack ../commitsonly.pack &&
 	git -C r1 verify-pack -v ../commitsonly.pack >objs &&
-	! grep -E "tree|blob" objs
+	test_grep ! -E "tree|blob" objs
 '
 
 test_expect_success 'grab tree directly when using tree:0' '
@@ -156,7 +156,7 @@ test_expect_success 'verify blob:limit=500 omits all blobs' '
 	git -C r2 index-pack ../filter.pack &&
 
 	git -C r2 verify-pack -v ../filter.pack >verify_result &&
-	! grep blob verify_result
+	test_grep ! blob verify_result
 '
 
 test_expect_success 'verify blob:limit=1000' '
@@ -166,7 +166,7 @@ test_expect_success 'verify blob:limit=1000' '
 	git -C r2 index-pack ../filter.pack &&
 
 	git -C r2 verify-pack -v ../filter.pack >verify_result &&
-	! grep blob verify_result
+	test_grep ! blob verify_result
 '
 
 test_expect_success 'verify blob:limit=1001' '
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 1c40f904f8..6cecfbeaa1 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -14,7 +14,7 @@ test_expect_success 'usage' '
 
 test_expect_success 'usage shown without sub-command' '
 	test_expect_code 129 git commit-graph 2>err &&
-	grep usage: err
+	test_grep usage: err
 '
 
 test_expect_success 'usage shown with an error on unknown sub-command' '
@@ -679,12 +679,12 @@ test_expect_success 'git fsck (checks commit-graph when config unset)' '
 
 test_expect_success 'git fsck shows commit-graph output with --progress' '
 	git -C "$TRASH_DIRECTORY/full" fsck --progress 2>err &&
-	grep "Verifying commits in commit graph" err
+	test_grep "Verifying commits in commit graph" err
 '
 
 test_expect_success 'git fsck suppresses commit-graph output with --no-progress' '
 	git -C "$TRASH_DIRECTORY/full" fsck --no-progress 2>err &&
-	! grep "Verifying commits in commit graph" err
+	test_grep ! "Verifying commits in commit graph" err
 '
 
 test_expect_success 'setup non-the_repository tests' '
@@ -962,7 +962,7 @@ test_expect_success 'stale commit cannot be parsed when traversing graph' '
 		git rev-parse HEAD~2 &&
 		# ... but fail when we are paranoid.
 		test_must_fail env GIT_COMMIT_GRAPH_PARANOIA=true git rev-parse HEAD~2 2>error &&
-		grep "error: commit $oid exists in commit-graph but not in the object database" error
+		test_grep "error: commit $oid exists in commit-graph but not in the object database" error
 	)
 '
 
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index 9154d9795f..68143cb5b7 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -130,7 +130,7 @@ test_expect_success 'corrupt idx reports errors' '
 	test_copy_bytes 1064 <backup-$idx >$objdir/pack/$idx &&
 
 	git -c core.multiPackIndex=true rev-list --objects --all 2>err &&
-	grep "index unavailable" err
+	test_grep "index unavailable" err
 '
 
 test_expect_success 'add more objects' '
@@ -326,7 +326,7 @@ test_expect_success 'preferred packs must be non-empty' '
 
 		test_must_fail git multi-pack-index write \
 			--preferred-pack=pack-$empty.pack 2>err &&
-		grep "with no objects" err
+		test_grep "with no objects" err
 	)
 '
 
@@ -548,14 +548,14 @@ test_expect_success 'git-fsck incorrect offset' '
 
 test_expect_success 'git fsck shows MIDX output with --progress' '
 	git fsck --progress 2>err &&
-	grep "Verifying OID order in multi-pack-index" err &&
-	grep "Verifying object offsets" err
+	test_grep "Verifying OID order in multi-pack-index" err &&
+	test_grep "Verifying object offsets" err
 '
 
 test_expect_success 'git fsck suppresses MIDX output with --no-progress' '
 	git fsck --no-progress 2>err &&
-	! grep "Verifying OID order in multi-pack-index" err &&
-	! grep "Verifying object offsets" err
+	test_grep ! "Verifying OID order in multi-pack-index" err &&
+	test_grep ! "Verifying object offsets" err
 '
 
 test_expect_success 'corrupt MIDX is not reused' '
@@ -1180,7 +1180,7 @@ test_expect_success 'usage shown without sub-command' '
 
 test_expect_success 'complains when run outside of a repository' '
 	nongit test_must_fail git multi-pack-index write 2>err &&
-	grep "not a git repository" err
+	test_grep "not a git repository" err
 '
 
 test_expect_success 'repack with delta islands' '
diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index 49a057cc2e..89c0c4f901 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -297,7 +297,7 @@ test_expect_success 'verify notices chain slice which is bogus (base)' '
 		echo "garbage" >$base_file &&
 		test_must_fail git commit-graph verify 2>test_err &&
 		grep -v "^+" test_err >err &&
-		grep "commit-graph file is too small" err
+		test_grep "commit-graph file is too small" err
 	)
 '
 
@@ -310,7 +310,7 @@ test_expect_success 'verify notices chain slice which is bogus (tip)' '
 		echo "garbage" >$tip_file &&
 		test_must_fail git commit-graph verify 2>test_err &&
 		grep -v "^+" test_err >err &&
-		grep "commit-graph file is too small" err
+		test_grep "commit-graph file is too small" err
 	)
 '
 
@@ -379,7 +379,7 @@ test_expect_success 'verify notices too-short chain file' '
 		echo "garbage" >$graphdir/commit-graph-chain &&
 		test_must_fail git commit-graph verify 2>test_err &&
 		grep -v "^+" test_err >err &&
-		grep "commit-graph chain file too small" err
+		test_grep "commit-graph chain file too small" err
 	)
 '
 
@@ -410,7 +410,7 @@ test_expect_success PERL_TEST_HELPERS 'reader bounds-checks base-graph chunk' '
 		git -c core.commitGraph=false log >expect.out &&
 		git -c core.commitGraph=true log >out 2>err &&
 		test_cmp expect.out out &&
-		grep "commit-graph base graphs chunk is too small" err
+		test_grep "commit-graph base graphs chunk is too small" err
 	)
 '
 
@@ -421,7 +421,7 @@ test_expect_success 'add octopus merge' '
 	git commit-graph write --reachable --split &&
 	git commit-graph verify --progress 2>err &&
 	test_line_count = 1 err &&
-	grep "Verifying commits in commit graph: 100% (18/18)" err &&
+	test_grep "Verifying commits in commit graph: 100% (18/18)" err &&
 	test_grep ! warning err &&
 	test_line_count = 3 $graphdir/commit-graph-chain
 '
diff --git a/t/t5325-reverse-index.sh b/t/t5325-reverse-index.sh
index 285c8b4a49..5493791938 100755
--- a/t/t5325-reverse-index.sh
+++ b/t/t5325-reverse-index.sh
@@ -65,7 +65,7 @@ test_expect_success 'index-pack can verify reverse indexes' '
 
 	test_must_fail git index-pack --rev-index --verify \
 		$packdir/pack-$pack.pack 2>err &&
-	grep "validation error" err
+	test_grep "validation error" err
 '
 
 test_expect_success 'index-pack infers reverse index name with -o' '
diff --git a/t/t5326-multi-pack-bitmaps.sh b/t/t5326-multi-pack-bitmaps.sh
index 62bd973d92..18464d2fc0 100755
--- a/t/t5326-multi-pack-bitmaps.sh
+++ b/t/t5326-multi-pack-bitmaps.sh
@@ -121,7 +121,7 @@ test_midx_bitmap_cases () {
 			EOF
 
 			test_must_fail git multi-pack-index write --bitmap 2>err &&
-			grep "doesn.t have full closure" err &&
+			test_grep "doesn.t have full closure" err &&
 			test_path_is_missing $midx
 		)
 	'
@@ -215,8 +215,8 @@ test_midx_bitmap_cases () {
 			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
 
 			test-tool bitmap list-commits | sort >bitmaps &&
-			grep "$(git rev-parse one)" bitmaps &&
-			grep "$(git rev-parse two)" bitmaps &&
+			test_grep "$(git rev-parse one)" bitmaps &&
+			test_grep "$(git rev-parse two)" bitmaps &&
 
 			rm -fr $midx-$(midx_checksum $objdir).bitmap &&
 			rm -fr $midx &&
@@ -229,8 +229,8 @@ test_midx_bitmap_cases () {
 			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
 
 			test-tool bitmap list-commits | sort >bitmaps &&
-			grep "$(git rev-parse one)" bitmaps &&
-			! grep "$(git rev-parse two)" bitmaps
+			test_grep "$(git rev-parse one)" bitmaps &&
+			test_grep ! "$(git rev-parse two)" bitmaps
 		)
 	'
 
@@ -258,7 +258,7 @@ test_midx_bitmap_cases () {
 			test_line_count = 1 before &&
 
 			(
-				grep -vf before commits.raw &&
+				test_grep -vf before commits.raw &&
 				# mark missing commits as preferred
 				sed "s/^/+/" before
 			) >snapshot &&
@@ -321,7 +321,7 @@ test_midx_bitmap_cases () {
 			git multi-pack-index write --bitmap --stdin-packs \
 				<packs 2>err &&
 
-			grep "bitmap without any objects" err &&
+			test_grep "bitmap without any objects" err &&
 
 			test_path_is_file $midx &&
 			test_path_is_missing $midx-$(midx_checksum $objdir).bitmap
@@ -344,7 +344,7 @@ test_midx_bitmap_cases () {
 
 			GIT_TEST_MIDX_READ_RIDX=0 \
 				git rev-list --use-bitmap-index HEAD 2>err &&
-			! grep "ignoring extra bitmap file" err
+			test_grep ! "ignoring extra bitmap file" err
 		)
 	'
 }
@@ -364,7 +364,7 @@ test_expect_success 'multi-pack-index write writes lookup table if enabled' '
 		git repack -ad &&
 		GIT_TRACE2_EVENT="$(pwd)/trace" \
 			git multi-pack-index write --bitmap &&
-		grep "\"label\":\"writing_lookup_table\"" trace
+		test_grep "\"label\":\"writing_lookup_table\"" trace
 	)
 '
 
@@ -432,7 +432,7 @@ test_expect_success 'tagged commits are selected for bitmapping' '
 
 		git rev-parse HEAD >want &&
 		test-tool bitmap list-commits >actual &&
-		grep $(cat want) actual
+		test_grep $(cat want) actual
 	)
 '
 
@@ -488,17 +488,17 @@ test_expect_success 'git fsck correctly identifies good and bad bitmaps' '
 
 	corrupt_file "$packbitmap" &&
 	test_must_fail git fsck 2>err &&
-	grep "bitmap file '\''$packbitmap'\'' has invalid checksum" err &&
+	test_grep "bitmap file '\''$packbitmap'\'' has invalid checksum" err &&
 
 	cp "$packbitmap.bak" "$packbitmap" &&
 	corrupt_file "$midxbitmap" &&
 	test_must_fail git fsck 2>err &&
-	grep "bitmap file '\''$midxbitmap'\'' has invalid checksum" err &&
+	test_grep "bitmap file '\''$midxbitmap'\'' has invalid checksum" err &&
 
 	corrupt_file "$packbitmap" &&
 	test_must_fail git fsck 2>err &&
-	grep "bitmap file '\''$midxbitmap'\'' has invalid checksum" err &&
-	grep "bitmap file '\''$packbitmap'\'' has invalid checksum" err
+	test_grep "bitmap file '\''$midxbitmap'\'' has invalid checksum" err &&
+	test_grep "bitmap file '\''$packbitmap'\'' has invalid checksum" err
 '
 
 test_expect_success 'corrupt MIDX with bitmap causes fallback' '
diff --git a/t/t5328-commit-graph-64bit-time.sh b/t/t5328-commit-graph-64bit-time.sh
index d8891e6a92..4e86aff509 100755
--- a/t/t5328-commit-graph-64bit-time.sh
+++ b/t/t5328-commit-graph-64bit-time.sh
@@ -80,7 +80,7 @@ test_expect_success PERL_TEST_HELPERS 'reader notices out-of-bounds generation o
 	git commit-graph write --reachable &&
 	corrupt_chunk_file $graph GDO2 clear &&
 	test_must_fail git log 2>err &&
-	grep "commit-graph overflow generation data is too small" err
+	test_grep "commit-graph overflow generation data is too small" err
 '
 
 test_done
diff --git a/t/t5329-pack-objects-cruft.sh b/t/t5329-pack-objects-cruft.sh
index 25ddda5cf3..12cda06373 100755
--- a/t/t5329-pack-objects-cruft.sh
+++ b/t/t5329-pack-objects-cruft.sh
@@ -468,8 +468,8 @@ test_expect_success 'cruft --local drops unreachable objects' '
 
 		test-tool pack-mtimes "$(basename $(ls $packdir/pack-*.mtimes))" \
 		       >objects &&
-		! grep $object objects &&
-		grep $cruft objects
+		test_grep ! $object objects &&
+		test_grep $cruft objects
 	)
 '
 
@@ -515,7 +515,7 @@ test_expect_success 'cruft objects are freshend via loose' '
 
 		test_path_is_missing "$loose" &&
 		test-tool pack-mtimes "$(basename "$(ls $packdir/pack-*.mtimes)")" >cruft &&
-		grep "$blob" cruft &&
+		test_grep "$blob" cruft &&
 
 		# write the same object again
 		git hash-object -w -t blob contents &&
@@ -657,7 +657,7 @@ test_expect_success 'multi-valued gc.recentObjectsHook' '
 		# ensure that a dirty exit halts cruft pack generation
 		git config --add gc.recentObjectsHook ./extra-tips.c &&
 		test_must_fail git repack --cruft --cruft-expiration=now -d 2>err &&
-		grep "unable to enumerate additional recent objects" err &&
+		test_grep "unable to enumerate additional recent objects" err &&
 
 		# and that the existing cruft pack is left alone
 		test_path_is_file "$mtimes"
diff --git a/t/t5334-incremental-multi-pack-index.sh b/t/t5334-incremental-multi-pack-index.sh
index 68a103d13d..f0b82b5f65 100755
--- a/t/t5334-incremental-multi-pack-index.sh
+++ b/t/t5334-incremental-multi-pack-index.sh
@@ -29,7 +29,7 @@ test_expect_success 'convert non-incremental MIDX to incremental' '
 	test_path_is_missing $packdir/multi-pack-index &&
 	test_path_is_file $midx_chain &&
 	test_line_count = 2 $midx_chain &&
-	grep $old_hash $midx_chain
+	test_grep $old_hash $midx_chain
 '
 
 compare_results_with_midx 'incremental MIDX'
diff --git a/t/t5335-compact-multi-pack-index.sh b/t/t5335-compact-multi-pack-index.sh
index ec1dafe89f..0f75ef2ccc 100755
--- a/t/t5335-compact-multi-pack-index.sh
+++ b/t/t5335-compact-multi-pack-index.sh
@@ -321,8 +321,8 @@ test_expect_success 'MIDX compaction with --no-write-chain-file' '
 		} >$midx_chain &&
 
 		test-tool read-midx $objdir $layer >midx.data &&
-		grep "^pack-B-.*\.idx" midx.data &&
-		grep "^pack-C-.*\.idx" midx.data
+		test_grep "^pack-B-.*\.idx" midx.data &&
+		test_grep "^pack-C-.*\.idx" midx.data
 
 	)
 '
diff --git a/t/t5351-unpack-large-objects.sh b/t/t5351-unpack-large-objects.sh
index d76eb4be93..7f621c5331 100755
--- a/t/t5351-unpack-large-objects.sh
+++ b/t/t5351-unpack-large-objects.sh
@@ -32,7 +32,7 @@ test_expect_success 'set memory limitation to 1MB' '
 test_expect_success 'unpack-objects failed under memory limitation' '
 	prepare_dest 2m &&
 	test_must_fail git -C dest.git unpack-objects <pack-$PACK.pack 2>err &&
-	grep "fatal: attempting to allocate" err
+	test_grep "fatal: attempting to allocate" err
 '
 
 test_expect_success 'unpack-objects works with memory limitation in dry-run mode' '
diff --git a/t/t5402-post-merge-hook.sh b/t/t5402-post-merge-hook.sh
index 915af2de95..c77aa56421 100755
--- a/t/t5402-post-merge-hook.sh
+++ b/t/t5402-post-merge-hook.sh
@@ -46,7 +46,7 @@ test_expect_success 'post-merge runs as expected ' '
 '
 
 test_expect_success 'post-merge from normal merge receives the right argument ' '
-	grep 0 clone1/.git/post-merge.args
+	test_grep 0 clone1/.git/post-merge.args
 '
 
 test_expect_success 'post-merge from squash merge runs as expected ' '
@@ -55,7 +55,7 @@ test_expect_success 'post-merge from squash merge runs as expected ' '
 '
 
 test_expect_success 'post-merge from squash merge receives the right argument ' '
-	grep 1 clone2/.git/post-merge.args
+	test_grep 1 clone2/.git/post-merge.args
 '
 
 test_done
diff --git a/t/t5403-post-checkout-hook.sh b/t/t5403-post-checkout-hook.sh
index cb0300b2d2..39009ce327 100755
--- a/t/t5403-post-checkout-hook.sh
+++ b/t/t5403-post-checkout-hook.sh
@@ -100,7 +100,7 @@ test_rebase () {
 		echo untracked >three.t &&
 		test_when_finished "rm three.t" &&
 		test_must_fail git rebase $args HEAD rebase-fast-forward 2>err &&
-		grep "untracked working tree files would be overwritten by checkout" err &&
+		test_grep "untracked working tree files would be overwritten by checkout" err &&
 		test_path_is_missing .git/post-checkout.args
 
 '
diff --git a/t/t5404-tracking-branches.sh b/t/t5404-tracking-branches.sh
index cc07889667..a1661d34f2 100755
--- a/t/t5404-tracking-branches.sh
+++ b/t/t5404-tracking-branches.sh
@@ -59,7 +59,7 @@ test_expect_success 'deleted branches have their tracking branches removed' '
 test_expect_success 'already deleted tracking branches ignored' '
 	git branch -d -r origin/b3 &&
 	git push origin :b3 >output 2>&1 &&
-	! grep "^error: " output
+	test_grep ! "^error: " output
 '
 
 test_done
diff --git a/t/t5406-remote-rejects.sh b/t/t5406-remote-rejects.sh
index dcbeb42082..bb293b7010 100755
--- a/t/t5406-remote-rejects.sh
+++ b/t/t5406-remote-rejects.sh
@@ -19,6 +19,6 @@ test_expect_success 'setup' '
 
 test_expect_success 'push reports error' 'test_must_fail git push 2>stderr'
 
-test_expect_success 'individual ref reports error' 'grep rejected stderr'
+test_expect_success 'individual ref reports error' 'test_grep rejected stderr'
 
 test_done
diff --git a/t/t5407-post-rewrite-hook.sh b/t/t5407-post-rewrite-hook.sh
index ad7f8c6f00..ed9896e27a 100755
--- a/t/t5407-post-rewrite-hook.sh
+++ b/t/t5407-post-rewrite-hook.sh
@@ -195,19 +195,19 @@ test_expect_success 'git rebase with failed pick' '
 		set_replace_editor todo &&
 		test_must_fail git rebase -i D D 2>err
 	) &&
-	grep "would be overwritten" err &&
+	test_grep "would be overwritten" err &&
 	rm bar &&
 
 	test_must_fail git rebase --continue 2>err &&
-	grep "would be overwritten" err &&
+	test_grep "would be overwritten" err &&
 	rm G &&
 
 	test_must_fail git rebase --continue 2>err &&
-	grep "would be overwritten" err &&
+	test_grep "would be overwritten" err &&
 	rm H &&
 
 	test_must_fail git rebase --continue 2>err &&
-	grep "would be overwritten" err &&
+	test_grep "would be overwritten" err &&
 	rm I &&
 
 	git rebase --continue &&
diff --git a/t/t5409-colorize-remote-messages.sh b/t/t5409-colorize-remote-messages.sh
index 3010913bb1..5da8b0ad64 100755
--- a/t/t5409-colorize-remote-messages.sh
+++ b/t/t5409-colorize-remote-messages.sh
@@ -32,70 +32,70 @@ test_expect_success 'setup' '
 test_expect_success 'keywords' '
 	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/keywords 2>output &&
 	test_decode_color <output >decoded &&
-	grep "<BOLD;RED>error<RESET>: error" decoded &&
-	grep "<YELLOW>hint<RESET>:" decoded &&
-	grep "<BOLD;GREEN>success<RESET>:" decoded &&
-	grep "<BOLD;GREEN>SUCCESS<RESET>" decoded &&
-	grep "<BOLD;YELLOW>warning<RESET>:" decoded
+	test_grep "<BOLD;RED>error<RESET>: error" decoded &&
+	test_grep "<YELLOW>hint<RESET>:" decoded &&
+	test_grep "<BOLD;GREEN>success<RESET>:" decoded &&
+	test_grep "<BOLD;GREEN>SUCCESS<RESET>" decoded &&
+	test_grep "<BOLD;YELLOW>warning<RESET>:" decoded
 '
 
 test_expect_success 'whole words at line start' '
 	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/whole-words 2>output &&
 	test_decode_color <output >decoded &&
-	grep "<YELLOW>hint<RESET>:" decoded &&
-	grep "hinting: not highlighted" decoded &&
-	grep "prefixerror: error" decoded
+	test_grep "<YELLOW>hint<RESET>:" decoded &&
+	test_grep "hinting: not highlighted" decoded &&
+	test_grep "prefixerror: error" decoded
 '
 
 test_expect_success 'short line' '
 	git -C child -c color.remote=always push -f origin HEAD:short-line 2>output &&
 	test_decode_color <output >decoded &&
-	grep "remote: Err" decoded
+	test_grep "remote: Err" decoded
 '
 
 test_expect_success 'case-insensitive' '
 	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/case-insensitive 2>output &&
 	test_decode_color <output >decoded &&
-	grep "<BOLD;RED>error<RESET>: error" decoded &&
-	grep "<BOLD;RED>ERROR<RESET>: also highlighted" decoded
+	test_grep "<BOLD;RED>error<RESET>: error" decoded &&
+	test_grep "<BOLD;RED>ERROR<RESET>: also highlighted" decoded
 '
 
 test_expect_success 'leading space' '
 	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/leading-space 2>output &&
 	test_decode_color <output >decoded &&
-	grep "  <BOLD;RED>error<RESET>: leading space" decoded
+	test_grep "  <BOLD;RED>error<RESET>: leading space" decoded
 '
 
 test_expect_success 'spaces only' '
 	git -C child -c color.remote=always push -f origin HEAD:only-space 2>output &&
 	test_decode_color <output >decoded &&
-	grep "remote:     " decoded
+	test_grep "remote:     " decoded
 '
 
 test_expect_success 'no coloring for redirected output' '
 	git --git-dir child/.git push -f origin HEAD:refs/heads/redirected-output 2>output &&
 	test_decode_color <output >decoded &&
-	grep "error: error" decoded
+	test_grep "error: error" decoded
 '
 
 test_expect_success 'push with customized color' '
 	git --git-dir child/.git -c color.remote=always -c color.remote.error=blue push -f origin HEAD:refs/heads/customized-color 2>output &&
 	test_decode_color <output >decoded &&
-	grep "<BLUE>error<RESET>:" decoded &&
-	grep "<BOLD;GREEN>success<RESET>:" decoded
+	test_grep "<BLUE>error<RESET>:" decoded &&
+	test_grep "<BOLD;GREEN>success<RESET>:" decoded
 '
 
 
 test_expect_success 'error in customized color' '
 	git --git-dir child/.git -c color.remote=always -c color.remote.error=i-am-not-a-color push -f origin HEAD:refs/heads/error-customized-color 2>output &&
 	test_decode_color <output >decoded &&
-	grep "<BOLD;GREEN>success<RESET>:" decoded
+	test_grep "<BOLD;GREEN>success<RESET>:" decoded
 '
 
 test_expect_success 'fallback to color.ui' '
 	git --git-dir child/.git -c color.ui=always push -f origin HEAD:refs/heads/fallback-color-ui 2>output &&
 	test_decode_color <output >decoded &&
-	grep "<BOLD;RED>error<RESET>: error" decoded
+	test_grep "<BOLD;RED>error<RESET>: error" decoded
 '
 
 test_expect_success 'disallow (color) control sequences in sideband' '
diff --git a/t/t5411/test-0013-bad-protocol.sh b/t/t5411/test-0013-bad-protocol.sh
index 8d22e17aee..83e4eb2df6 100644
--- a/t/t5411/test-0013-bad-protocol.sh
+++ b/t/t5411/test-0013-bad-protocol.sh
@@ -62,8 +62,8 @@ test_expect_success "proc-receive: bad protocol (hook --die-read-version, $PROTO
 	 ! [remote rejected] HEAD -> refs/for/main/topic (fail to run proc-receive hook)
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-read-version option" out-$test_count &&
-	grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-read-version option" out-$test_count &&
+	test_grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-\EOF
 	<COMMIT-A> refs/heads/main
@@ -93,8 +93,8 @@ test_expect_success "proc-receive: bad protocol (hook --die-write-version, $PROT
 	 ! [remote rejected] HEAD -> refs/for/main/topic (fail to run proc-receive hook)
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-write-version option" out-$test_count &&
-	grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-write-version option" out-$test_count &&
+	test_grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
@@ -124,7 +124,7 @@ test_expect_success "proc-receive: bad protocol (hook --die-read-commands, $PROT
 	 ! [remote rejected] HEAD -> refs/for/main/topic (fail to run proc-receive hook)
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-read-commands option" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-read-commands option" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
@@ -156,7 +156,7 @@ test_expect_success "proc-receive: bad protocol (hook --die-read-push-options, $
 	 ! [remote rejected] HEAD -> refs/for/main/topic (fail to run proc-receive hook)
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-read-push-options option" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-read-push-options option" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
@@ -186,7 +186,7 @@ test_expect_success "proc-receive: bad protocol (hook --die-write-report, $PROTO
 	 ! [remote rejected] HEAD -> refs/for/main/topic (fail to run proc-receive hook)
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-write-report option" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-write-report option" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
diff --git a/t/t5411/test-0014-bad-protocol--porcelain.sh b/t/t5411/test-0014-bad-protocol--porcelain.sh
index 298a3d1fec..6258e575ff 100644
--- a/t/t5411/test-0014-bad-protocol--porcelain.sh
+++ b/t/t5411/test-0014-bad-protocol--porcelain.sh
@@ -62,8 +62,8 @@ test_expect_success "proc-receive: bad protocol (hook --die-read-version, $PROTO
 	Done
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-read-version option" out-$test_count &&
-	grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-read-version option" out-$test_count &&
+	test_grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
@@ -93,8 +93,8 @@ test_expect_success "proc-receive: bad protocol (hook --die-write-version, $PROT
 	Done
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-write-version option" out-$test_count &&
-	grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-write-version option" out-$test_count &&
+	test_grep "remote: error: fail to negotiate version with proc-receive hook" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
@@ -124,7 +124,7 @@ test_expect_success "proc-receive: bad protocol (hook --die-read-commands, $PROT
 	Done
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-read-commands option" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-read-commands option" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
@@ -156,7 +156,7 @@ test_expect_success "proc-receive: bad protocol (hook --die-read-push-options, $
 	Done
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-read-push-options option" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-read-push-options option" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
@@ -186,7 +186,7 @@ test_expect_success "proc-receive: bad protocol (hook --die-write-report, $PROTO
 	Done
 	EOF
 	test_cmp expect actual &&
-	grep "remote: fatal: die with the --die-write-report option" out-$test_count &&
+	test_grep "remote: fatal: die with the --die-write-report option" out-$test_count &&
 
 	test_cmp_refs -C "$upstream" <<-EOF
 	<COMMIT-A> refs/heads/main
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index 649a615ec9..6c1edf2117 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -135,15 +135,15 @@ test_expect_success 'single given branch clone' '
 	GIT_TRACE2_EVENT="$(pwd)/branch-a/trace2_event" \
 		git clone --single-branch --branch A "file://$(pwd)/." branch-a &&
 	test_must_fail git --git-dir=branch-a/.git rev-parse origin/B &&
-	grep \"fetch-info\".*\"haves\":0 branch-a/trace2_event &&
-	grep \"fetch-info\".*\"wants\":1 branch-a/trace2_event
+	test_grep \"fetch-info\".*\"haves\":0 branch-a/trace2_event &&
+	test_grep \"fetch-info\".*\"wants\":1 branch-a/trace2_event
 '
 
 test_expect_success 'clone shallow depth 1' '
 	GIT_TRACE2_EVENT="$(pwd)/shallow0/trace2_event" \
 		git clone --no-single-branch --depth 1 "file://$(pwd)/." shallow0 &&
 	test "$(git --git-dir=shallow0/.git rev-list --count HEAD)" = 1 &&
-	grep \"fetch-info\".*\"depth\":1 shallow0/trace2_event
+	test_grep \"fetch-info\".*\"depth\":1 shallow0/trace2_event
 '
 
 test_expect_success 'clone shallow depth 1 with fsck' '
@@ -167,7 +167,7 @@ test_expect_success 'clone shallow object count' '
 		cd shallow &&
 		git count-objects -v
 	) > count.shallow &&
-	grep "^in-pack: 12" count.shallow
+	test_grep "^in-pack: 12" count.shallow
 '
 
 test_expect_success 'clone shallow object count (part 2)' '
@@ -230,7 +230,7 @@ test_expect_success 'clone shallow object count' '
 		cd shallow &&
 		git count-objects -v
 	) > count.shallow &&
-	grep "^count: 6" count.shallow
+	test_grep "^count: 6" count.shallow
 '
 
 test_expect_success 'add two more (part 2)' '
@@ -243,8 +243,8 @@ test_expect_success 'deepening pull in shallow repo' '
 		cd shallow &&
 		GIT_TRACE2_EVENT="$(pwd)/trace2_event" \
 			git pull --depth 4 .. B &&
-		grep \"fetch-info\".*\"depth\":4 trace2_event &&
-		grep \"fetch-info\".*\"shallows\":2 trace2_event
+		test_grep \"fetch-info\".*\"depth\":4 trace2_event &&
+		test_grep \"fetch-info\".*\"shallows\":2 trace2_event
 	)
 '
 
@@ -253,7 +253,7 @@ test_expect_success 'clone shallow object count' '
 		cd shallow &&
 		git count-objects -v
 	) > count.shallow &&
-	grep "^count: 12" count.shallow
+	test_grep "^count: 12" count.shallow
 '
 
 test_expect_success 'deepening fetch in shallow repo' '
@@ -268,7 +268,7 @@ test_expect_success 'clone shallow object count' '
 		cd shallow &&
 		git count-objects -v
 	) > count.shallow &&
-	grep "^count: 18" count.shallow
+	test_grep "^count: 18" count.shallow
 '
 
 test_expect_success 'pull in shallow repo with missing merge base' '
@@ -298,7 +298,7 @@ test_expect_success 'clone shallow object count' '
 		git prune &&
 		git count-objects -v
 	) > count.shallow &&
-	grep "^count: 54" count.shallow
+	test_grep "^count: 54" count.shallow
 '
 
 test_expect_success 'fetch --no-shallow on full repo' '
@@ -319,8 +319,8 @@ test_expect_success 'turn shallow to complete repository' '
 			git fetch --unshallow &&
 		! test -f .git/shallow &&
 		git fsck --full &&
-		grep \"fetch-info\".*\"shallows\":2 trace2_event &&
-		grep \"fetch-info\".*\"depth\":2147483647 trace2_event
+		test_grep \"fetch-info\".*\"shallows\":2 trace2_event &&
+		test_grep \"fetch-info\".*\"depth\":2147483647 trace2_event
 	)
 '
 
@@ -333,7 +333,7 @@ test_expect_success 'clone shallow object count' '
 		cd shallow2 &&
 		git count-objects -v
 	) > count.shallow2 &&
-	grep "^in-pack: 3" count.shallow2
+	test_grep "^in-pack: 3" count.shallow2
 '
 
 test_expect_success 'clone shallow with --branch' '
@@ -446,7 +446,7 @@ test_expect_success 'in_vain reset upon ACK' '
 	# and should reset in_vain. This allows negotiation to continue until
 	# the client reports that first_anotherbranch_commit is common.
 	GIT_TRACE2_EVENT="$(pwd)/trace2" git -C myclient fetch --progress origin main 2>log &&
-	grep \"key\":\"total_rounds\",\"value\":\"6\" trace2 &&
+	test_grep \"key\":\"total_rounds\",\"value\":\"6\" trace2 &&
 	test_grep "Total 3 " log
 '
 
@@ -852,7 +852,7 @@ test_expect_success 'fetch shallow since ...' '
 	two
 	EOF
 	test_cmp expected actual &&
-	grep \"fetch-info\".*\"deepen-since\":true shallow11/trace2_event
+	test_grep \"fetch-info\".*\"deepen-since\":true shallow11/trace2_event
 '
 
 test_expect_success 'clone shallow since selects no commits' '
@@ -935,7 +935,7 @@ test_expect_success 'fetch exclude tag one as revision' '
 	test_when_finished rm -f rev err &&
 	git -C shallow-exclude rev-parse one >rev &&
 	test_must_fail git -C shallow12 fetch --shallow-exclude $(cat rev) origin 2>err &&
-	grep "deepen-not is not a ref:" err
+	test_grep "deepen-not is not a ref:" err
 '
 
 test_expect_success 'fetching deepen' '
@@ -1059,9 +1059,9 @@ test_expect_success 'filtering by size' '
 	commit=$(git -C server rev-parse HEAD) &&
 	blob=$(git hash-object server/one.t) &&
 	git -C client rev-list --objects --missing=allow-any "$commit" >oids &&
-	! grep "$blob" oids &&
+	test_grep ! "$blob" oids &&
 
-	grep \"fetch-info\".*\"filter\":\"blob:limit\" client/trace2_event
+	test_grep \"fetch-info\".*\"filter\":\"blob:limit\" client/trace2_event
 '
 
 test_expect_success 'filtering by size has no effect if support for it is not advertised' '
@@ -1076,7 +1076,7 @@ test_expect_success 'filtering by size has no effect if support for it is not ad
 	commit=$(git -C server rev-parse HEAD) &&
 	blob=$(git hash-object server/one.t) &&
 	git -C client rev-list --objects --missing=allow-any "$commit" >oids &&
-	grep "$blob" oids &&
+	test_grep "$blob" oids &&
 
 	test_grep "filtering not recognized by server" err
 '
diff --git a/t/t5504-fetch-receive-strict.sh b/t/t5504-fetch-receive-strict.sh
index 438250c75e..75b2b87999 100755
--- a/t/t5504-fetch-receive-strict.sh
+++ b/t/t5504-fetch-receive-strict.sh
@@ -298,13 +298,13 @@ test_expect_success 'push with receive.fsck.missingEmail=warn' '
 	git --git-dir=dst/.git config \
 		receive.fsck.missingEmail warn &&
 	git push --porcelain dst bogus >act 2>&1 &&
-	grep "missingEmail" act &&
+	test_grep "missingEmail" act &&
 	test_grep "skipping unknown msg id.*whatever" act &&
 	git --git-dir=dst/.git branch -D bogus &&
 	git --git-dir=dst/.git config --add \
 		receive.fsck.missingEmail ignore &&
 	git push --porcelain dst bogus >act 2>&1 &&
-	! grep "missingEmail" act
+	test_grep ! "missingEmail" act
 '
 
 test_expect_success 'fetch with fetch.fsck.missingEmail=warn' '
@@ -326,7 +326,7 @@ test_expect_success 'fetch with fetch.fsck.missingEmail=warn' '
 	git --git-dir=dst/.git config \
 		fetch.fsck.missingEmail warn &&
 	git --git-dir=dst/.git fetch "file://$(pwd)" $refspec >act 2>&1 &&
-	grep "missingEmail" act &&
+	test_grep "missingEmail" act &&
 	test_grep "Skipping unknown msg id.*whatever" act &&
 	rm -rf dst &&
 	git init dst &&
@@ -334,7 +334,7 @@ test_expect_success 'fetch with fetch.fsck.missingEmail=warn' '
 	git --git-dir=dst/.git config \
 		fetch.fsck.missingEmail ignore &&
 	git --git-dir=dst/.git fetch "file://$(pwd)" $refspec >act 2>&1 &&
-	! grep "missingEmail" act
+	test_grep ! "missingEmail" act
 '
 
 test_expect_success \
@@ -345,7 +345,7 @@ test_expect_success \
 	git --git-dir=dst/.git config \
 		receive.fsck.unterminatedheader warn &&
 	test_must_fail git push --porcelain dst HEAD >act 2>&1 &&
-	grep "Cannot demote unterminatedheader" act
+	test_grep "Cannot demote unterminatedheader" act
 '
 
 test_expect_success \
@@ -356,7 +356,7 @@ test_expect_success \
 	git --git-dir=dst/.git config \
 		fetch.fsck.unterminatedheader warn &&
 	test_must_fail git --git-dir=dst/.git fetch "file://$(pwd)" HEAD &&
-	grep "Cannot demote unterminatedheader" act
+	test_grep "Cannot demote unterminatedheader" act
 '
 
 test_expect_success PERL_TEST_HELPERS 'badFilemode is not a strict error' '
@@ -373,7 +373,7 @@ test_expect_success PERL_TEST_HELPERS 'badFilemode is not a strict error' '
 	git -C dst.git config transfer.fsckObjects true &&
 
 	git -C badmode.git push ../dst.git $tree:refs/tags/tree 2>err &&
-	grep "$tree: badFilemode" err
+	test_grep "$tree: badFilemode" err
 '
 
 test_done
diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index e592c0bcde..6f5e86dede 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -91,28 +91,28 @@ test_expect_success 'filters for promisor remotes are listed by git remote -v' '
 	test_when_finished "rm -rf pc" &&
 	git clone --filter=blob:none "file://$(pwd)/srv.bare" pc &&
 	git -C pc remote -v >out &&
-	grep "srv.bare (fetch) \[blob:none\]" out &&
+	test_grep "srv.bare (fetch) \[blob:none\]" out &&
 
 	git -C pc config remote.origin.partialCloneFilter object:type=commit &&
 	git -C pc remote -v >out &&
-	grep "srv.bare (fetch) \[object:type=commit\]" out
+	test_grep "srv.bare (fetch) \[object:type=commit\]" out
 '
 
 test_expect_success 'filters should not be listed for non promisor remotes (remote -v)' '
 	test_when_finished "rm -rf pc" &&
 	git clone one pc &&
 	git -C pc remote -v >out &&
-	! grep "(fetch) \[.*\]" out
+	test_grep ! "(fetch) \[.*\]" out
 '
 
 test_expect_success 'filters are listed by git remote -v only' '
 	test_when_finished "rm -rf pc" &&
 	git clone --filter=blob:none "file://$(pwd)/srv.bare" pc &&
 	git -C pc remote >out &&
-	! grep "\[blob:none\]" out &&
+	test_grep ! "\[blob:none\]" out &&
 
 	git -C pc remote show >out &&
-	! grep "\[blob:none\]" out
+	test_grep ! "\[blob:none\]" out
 '
 
 test_expect_success 'check remote-tracking' '
@@ -261,7 +261,7 @@ test_expect_success 'without subcommand accepts -v' '
 
 test_expect_success 'without subcommand does not take arguments' '
 	test_expect_code 129 git -C test remote origin 2>err &&
-	grep "^error: unknown subcommand:" err
+	test_grep "^error: unknown subcommand:" err
 '
 
 cat >test/expect <<EOF
@@ -798,7 +798,7 @@ test_expect_success 'add --no-tags' '
 		cd add-no-tags &&
 		git init &&
 		git remote add -f --no-tags origin ../one &&
-		grep tagOpt .git/config &&
+		test_grep tagOpt .git/config &&
 		git tag -l some-tag >../test/output &&
 		git tag -l foobar-tag >../test/output &&
 		git config remote.origin.tagopt >>../test/output
@@ -972,7 +972,7 @@ test_expect_success 'rename a remote' '
 		GIT_TRACE2_EVENT=$(pwd)/trace \
 			git remote rename --progress origin upstream &&
 		test_region progress "Renaming remote references" trace &&
-		grep "pushRemote" .git/config &&
+		test_grep "pushRemote" .git/config &&
 		test -z "$(git for-each-ref refs/remotes/origin)" &&
 		test "$(git symbolic-ref refs/remotes/upstream/HEAD)" = "refs/remotes/upstream/main" &&
 		test "$(git rev-parse upstream/main)" = "$(git rev-parse main)" &&
@@ -989,7 +989,7 @@ test_expect_success 'rename a remote renames repo remote.pushDefault' '
 		cd four.1 &&
 		git config remote.pushDefault origin &&
 		git remote rename origin upstream &&
-		grep pushDefault .git/config &&
+		test_grep pushDefault .git/config &&
 		test "$(git config --local remote.pushDefault)" = "upstream"
 	)
 '
@@ -1198,7 +1198,7 @@ test_expect_success 'remote prune to cause a dangling symref' '
 		cd eight &&
 		git branch -a
 	) 2>err &&
-	! grep "points nowhere" err &&
+	test_grep ! "points nowhere" err &&
 	(
 		cd eight &&
 		test_must_fail git branch nomore origin
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index eca9a973b5..a0bbbce0f7 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -750,7 +750,7 @@ test_expect_success 'fetch from GIT URL with a non-applying branch.<name>.merge
 # the strange name is: a\!'b
 test_expect_success 'quoting of a strangely named repo' '
 	test_must_fail git fetch "a\\!'\''b" > result 2>&1 &&
-	grep "fatal: '\''a\\\\!'\''b'\''" result
+	test_grep "fatal: '\''a\\\\!'\''b'\''" result
 '
 
 test_expect_success 'bundle should record HEAD correctly' '
@@ -904,14 +904,14 @@ test_expect_success 'fetch --dry-run does not touch FETCH_HEAD, but still prints
 	rm -f .git/FETCH_HEAD err &&
 	git fetch --dry-run . 2>err &&
 	! test -f .git/FETCH_HEAD &&
-	grep FETCH_HEAD err
+	test_grep FETCH_HEAD err
 '
 
 test_expect_success '--no-write-fetch-head does not touch FETCH_HEAD, and does not print what would be written' '
 	rm -f .git/FETCH_HEAD err &&
 	git fetch --no-write-fetch-head . 2>err &&
 	! test -f .git/FETCH_HEAD &&
-	! grep FETCH_HEAD err
+	test_grep ! FETCH_HEAD err
 '
 
 test_expect_success '--write-fetch-head gets defeated by --dry-run' '
@@ -1329,7 +1329,7 @@ test_expect_success 'fetching with auto-gc does not lock up' '
 		git config maintenance.strategy gc &&
 		GIT_ASK_YESNO="$TRASH_DIRECTORY/askyesno" git fetch --verbose >fetch.out 2>&1 &&
 		test_grep "Auto packing the repository" fetch.out &&
-		! grep "Should I try again" fetch.out
+		test_grep ! "Should I try again" fetch.out
 	)
 '
 
@@ -1338,7 +1338,7 @@ do
 	test_expect_success "$section.hideRefs affects connectivity check" '
 		GIT_TRACE="$PWD"/trace git -c $section.hideRefs=refs -c \
 			$section.hideRefs="!refs/tags/" fetch &&
-		grep "git rev-list .*--exclude-hidden=fetch" trace
+		test_grep "git rev-list .*--exclude-hidden=fetch" trace
 	'
 done
 
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index 5930f55186..fe44f39871 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -245,8 +245,8 @@ do
 		git config --add $configsection.hiderefs "!refs/tags/magic" &&
 		git config --add $configsection.hiderefs refs/tags/magic/one &&
 		git ls-remote . >actual &&
-		grep refs/tags/magic/two actual &&
-		! grep refs/tags/magic/one actual
+		test_grep refs/tags/magic/two actual &&
+		test_grep ! refs/tags/magic/one actual
 	'
 
 done
@@ -255,13 +255,13 @@ test_expect_success 'overrides work between mixed transfer/upload-pack hideRefs'
 	test_config uploadpack.hiderefs refs/tags &&
 	test_config transfer.hiderefs "!refs/tags/magic" &&
 	git ls-remote . >actual &&
-	grep refs/tags/magic actual
+	test_grep refs/tags/magic actual
 '
 
 test_expect_success 'protocol v2 supports hiderefs' '
 	test_config uploadpack.hiderefs refs/tags &&
 	git -c protocol.version=2 ls-remote . >actual &&
-	! grep refs/tags actual
+	test_grep ! refs/tags actual
 '
 
 test_expect_success 'ls-remote --symref' '
diff --git a/t/t5514-fetch-multiple.sh b/t/t5514-fetch-multiple.sh
index 523aff6268..5d79472c39 100755
--- a/t/t5514-fetch-multiple.sh
+++ b/t/t5514-fetch-multiple.sh
@@ -217,7 +217,7 @@ test_expect_success 'parallel' '
 
 	test_must_fail env GIT_TRACE="$PWD/trace" \
 		git fetch --jobs=2 --multiple one two 2>err &&
-	grep "preparing to run up to 2 tasks" trace &&
+	test_grep "preparing to run up to 2 tasks" trace &&
 	test_grep "could not fetch .one.*128" err &&
 	test_grep "could not fetch .two.*128" err
 '
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 4d1672de1e..49d01f74d5 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -124,7 +124,7 @@ do
 	do
 		test_expect_success "reject 'git $cmd --no-$opt'" '
 			test_must_fail git $cmd --no-$opt 2>err &&
-			grep "unknown option .no-$opt" err
+			test_grep "unknown option .no-$opt" err
 		'
 	done
 done
@@ -212,7 +212,7 @@ test_expect_success 'push with negotiation' '
 	GIT_TRACE2_EVENT="$(pwd)/event" \
 		git -c protocol.version=2 -c push.negotiate=1 \
 		push testrepo refs/heads/main:refs/remotes/origin/main &&
-	grep \"key\":\"total_rounds\",\"value\":\"1\" event &&
+	test_grep \"key\":\"total_rounds\",\"value\":\"1\" event &&
 	grep_wrote 2 event # 1 commit, 1 tree
 '
 
@@ -250,8 +250,8 @@ test_expect_success 'push with negotiation does not attempt to fetch submodules'
 	GIT_TRACE2_EVENT="$(pwd)/event"  git -c submodule.recurse=true \
 		-c protocol.version=2 -c push.negotiate=1 \
 		push testrepo refs/heads/main:refs/remotes/origin/main 2>err &&
-	grep \"key\":\"total_rounds\",\"value\":\"1\" event &&
-	! grep "Fetching submodule" err
+	test_grep \"key\":\"total_rounds\",\"value\":\"1\" event &&
+	test_grep ! "Fetching submodule" err
 '
 
 test_expect_success 'push with negotiation and remote.<name>.negotiationInclude' '
@@ -637,7 +637,7 @@ test_expect_success 'push rejects empty branch name entries' '
 	test_config branch.main.remote one &&
 	test_config branch.main.merge refs/heads/main &&
 	test_must_fail git push 2>err &&
-	grep "bad config variable .branch\.\." err
+	test_grep "bad config variable .branch\.\." err
 '
 
 test_expect_success 'push ignores "branch." config without subsection' '
@@ -923,7 +923,7 @@ test_expect_success 'warn on push to HEAD of non-bare repository' '
 		git config receive.denyCurrentBranch warn
 	) &&
 	git push testrepo main 2>stderr &&
-	grep "warning: updating the current branch" stderr
+	test_grep "warning: updating the current branch" stderr
 '
 
 test_expect_success 'deny push to HEAD of non-bare repository' '
@@ -945,7 +945,7 @@ test_expect_success 'allow push to HEAD of bare repository (bare)' '
 		git config core.bare true
 	) &&
 	git push testrepo main 2>stderr &&
-	! grep "warning: updating the current branch" stderr
+	test_grep ! "warning: updating the current branch" stderr
 '
 
 test_expect_success 'allow push to HEAD of non-bare repository (config)' '
@@ -956,7 +956,7 @@ test_expect_success 'allow push to HEAD of non-bare repository (config)' '
 		git config receive.denyCurrentBranch false
 	) &&
 	git push testrepo main 2>stderr &&
-	! grep "warning: updating the current branch" stderr
+	test_grep ! "warning: updating the current branch" stderr
 '
 
 test_expect_success !WITH_BREAKING_CHANGES 'fetch with branches' '
@@ -1068,7 +1068,7 @@ test_expect_success 'push into aliased refs (inconsistent)' '
 		git commit -a -m child2 &&
 		git branch bar &&
 		test_must_fail git push ../child1 foo bar 2>stderr &&
-		grep "refusing inconsistent update" stderr
+		test_grep "refusing inconsistent update" stderr
 	)
 '
 
@@ -1161,7 +1161,7 @@ test_expect_success 'push --porcelain' '
 test_expect_success 'push --porcelain bad url' '
 	mk_empty testrepo &&
 	test_must_fail git push >.git/bar --porcelain asdfasdfasd refs/heads/main:refs/remotes/origin/main &&
-	! grep -q Done .git/bar
+	test_grep ! Done .git/bar
 '
 
 test_expect_success 'push --porcelain rejected' '
diff --git a/t/t5520-pull.sh b/t/t5520-pull.sh
index 0e0019347e..4ae3b4fd59 100755
--- a/t/t5520-pull.sh
+++ b/t/t5520-pull.sh
@@ -356,8 +356,8 @@ test_expect_success '--rebase with rebase.autostash succeeds on ff' '
 	echo "dirty" >>dst/file &&
 	test_config -C dst rebase.autostash true &&
 	git -C dst pull --rebase >actual 2>&1 &&
-	grep -q "Fast-forward" actual &&
-	grep -q "Applied autostash." actual
+	test_grep "Fast-forward" actual &&
+	test_grep "Applied autostash." actual
 '
 
 test_expect_success '--rebase with conflicts shows advice' '
diff --git a/t/t5524-pull-msg.sh b/t/t5524-pull-msg.sh
index b2be3605f5..493156a2b8 100755
--- a/t/t5524-pull-msg.sh
+++ b/t/t5524-pull-msg.sh
@@ -31,7 +31,7 @@ test_expect_success pull '
 	git pull --no-rebase --log &&
 	git log -2 &&
 	git cat-file commit HEAD >result &&
-	grep Dollar result
+	test_grep Dollar result
 )
 '
 
@@ -44,8 +44,8 @@ test_expect_success '--log=1 limits shortlog length' '
 	git pull --no-rebase --log=1 &&
 	git log -3 &&
 	git cat-file commit HEAD >result &&
-	grep Dollar result &&
-	! grep "second commit" result
+	test_grep Dollar result &&
+	test_grep ! "second commit" result
 )
 '
 
diff --git a/t/t5526-fetch-submodules.sh b/t/t5526-fetch-submodules.sh
index 1242ee9185..7b3b7359da 100755
--- a/t/t5526-fetch-submodules.sh
+++ b/t/t5526-fetch-submodules.sh
@@ -199,7 +199,7 @@ test_expect_success "fetch --recurse-submodules -j2 has the same output behaviou
 	) &&
 	test_must_be_empty actual.out &&
 	verify_fetch_result actual.err &&
-	grep "2 tasks" trace.out
+	test_grep "2 tasks" trace.out
 '
 
 test_expect_success "fetch alone only fetches superproject" '
@@ -723,25 +723,25 @@ test_expect_success 'fetching submodules respects parallel settings' '
 	(
 		cd downstream &&
 		GIT_TRACE=$(pwd)/trace.out git fetch &&
-		grep "1 tasks" trace.out &&
+		test_grep "1 tasks" trace.out &&
 		>trace.out &&
 
 		GIT_TRACE=$(pwd)/trace.out git fetch --jobs 7 &&
-		grep "7 tasks" trace.out &&
+		test_grep "7 tasks" trace.out &&
 		>trace.out &&
 
 		git config submodule.fetchJobs 8 &&
 		GIT_TRACE=$(pwd)/trace.out git fetch &&
-		grep "8 tasks" trace.out &&
+		test_grep "8 tasks" trace.out &&
 		>trace.out &&
 
 		GIT_TRACE=$(pwd)/trace.out git fetch --jobs 9 &&
-		grep "9 tasks" trace.out &&
+		test_grep "9 tasks" trace.out &&
 		>trace.out &&
 
 		GIT_TRACE=$(pwd)/trace.out git -c submodule.fetchJobs=0 fetch &&
-		grep "preparing to run up to [0-9]* tasks" trace.out &&
-		! grep "up to 0 tasks" trace.out &&
+		test_grep "preparing to run up to [0-9]* tasks" trace.out &&
+		test_grep ! "up to 0 tasks" trace.out &&
 		>trace.out
 	)
 '
@@ -1259,7 +1259,7 @@ test_expect_success "fetch --all with --no-recurse-submodules only fetches super
 		git config submodule.recurse true &&
 		git fetch --all --no-recurse-submodules 2>../fetch-log
 	) &&
-	! grep "Fetching submodule" fetch-log
+	test_grep ! "Fetching submodule" fetch-log
 '
 
 test_done
diff --git a/t/t5529-push-errors.sh b/t/t5529-push-errors.sh
index 80b06a0cd2..35b1f212a8 100755
--- a/t/t5529-push-errors.sh
+++ b/t/t5529-push-errors.sh
@@ -44,14 +44,14 @@ test_expect_success 'detect missing sha1 expressions early' '
 # 'builtin/push.c:set_refspecs()' and we want to test that regression.
 test_expect_success 'detect empty remote with existing local ref' '
 	test_must_fail git push "" main 2> stderr &&
-	grep "fatal: bad repository ${SQ}${SQ}" stderr
+	test_grep "fatal: bad repository ${SQ}${SQ}" stderr
 '
 
 # While similar to the previous test, here we want to ensure that
 # even targeted refspecs are handled.
 test_expect_success 'detect empty remote with targeted refspec' '
 	test_must_fail git push "" HEAD:refs/heads/main 2> stderr &&
-	grep "fatal: bad repository ${SQ}${SQ}" stderr
+	test_grep "fatal: bad repository ${SQ}${SQ}" stderr
 '
 
 test_expect_success 'detect ambiguous refs early' '
diff --git a/t/t5530-upload-pack-error.sh b/t/t5530-upload-pack-error.sh
index d40292cfb7..25d409fc94 100755
--- a/t/t5530-upload-pack-error.sh
+++ b/t/t5530-upload-pack-error.sh
@@ -44,16 +44,16 @@ test_expect_success 'upload-pack fails due to error in rev-list' '
 		$(($hexsz + 10)) $(git rev-parse HEAD) \
 		$(($hexsz + 12)) $(git rev-parse HEAD^) >input &&
 	test_must_fail git upload-pack . <input >/dev/null 2>output.err &&
-	grep "bad tree object" output.err
+	test_grep "bad tree object" output.err
 '
 
 test_expect_success 'upload-pack fails due to bad want (no object)' '
 	printf "%04xwant %s multi_ack_detailed\n00000009done\n0000" \
 		$(($hexsz + 29)) $(test_oid deadbeef) >input &&
 	test_must_fail git upload-pack . <input >output 2>output.err &&
-	grep "not our ref" output.err &&
-	grep "ERR" output &&
-	! grep multi_ack_detailed output.err
+	test_grep "not our ref" output.err &&
+	test_grep "ERR" output &&
+	test_grep ! multi_ack_detailed output.err
 '
 
 test_expect_success 'upload-pack fails due to bad want (not tip)' '
@@ -61,17 +61,17 @@ test_expect_success 'upload-pack fails due to bad want (not tip)' '
 	printf "%04xwant %s multi_ack_detailed\n00000009done\n0000" \
 		$(($hexsz + 29)) "$oid" >input &&
 	test_must_fail git upload-pack . <input >output 2>output.err &&
-	grep "not our ref" output.err &&
-	grep "ERR" output &&
-	! grep multi_ack_detailed output.err
+	test_grep "not our ref" output.err &&
+	test_grep "ERR" output &&
+	test_grep ! multi_ack_detailed output.err
 '
 
 test_expect_success 'upload-pack fails due to error in pack-objects enumeration' '
 	printf "%04xwant %s\n00000009done\n0000" \
 		$((hexsz + 10)) $(git rev-parse HEAD) >input &&
 	test_must_fail git upload-pack . <input >/dev/null 2>output.err &&
-	grep "bad tree object" output.err &&
-	grep "pack-objects died" output.err
+	test_grep "bad tree object" output.err &&
+	test_grep "pack-objects died" output.err
 '
 
 test_expect_success 'upload-pack tolerates EOF just after stateless client wants' '
diff --git a/t/t5531-deep-submodule-push.sh b/t/t5531-deep-submodule-push.sh
index 05debd1134..7d239dd31f 100755
--- a/t/t5531-deep-submodule-push.sh
+++ b/t/t5531-deep-submodule-push.sh
@@ -559,7 +559,7 @@ test_expect_success 'push with push.recurseSubmodules=only on superproject and t
 	test_must_fail git -C upstream rev-parse refs/heads/downstream-branch &&
 	git -C upstream/sub rev-parse refs/heads/downstream-branch &&
 	git -C upstream/sub/deepsub rev-parse refs/heads/downstream-branch &&
-	grep "recursing into submodule with push.recurseSubmodules=only; using on-demand instead" err
+	test_grep "recursing into submodule with push.recurseSubmodules=only; using on-demand instead" err
 '
 
 test_expect_success 'push propagating the remotes name to a submodule' '
diff --git a/t/t5532-fetch-proxy.sh b/t/t5532-fetch-proxy.sh
index 95d0f33b29..ccbca7c2f2 100755
--- a/t/t5532-fetch-proxy.sh
+++ b/t/t5532-fetch-proxy.sh
@@ -52,7 +52,7 @@ test_expect_success 'fetch through proxy works' '
 
 test_expect_success 'funny hostnames are rejected before running proxy' '
 	test_must_fail git fetch git://-remote/repo.git 2>stderr &&
-	! grep "proxying for" stderr
+	test_grep ! "proxying for" stderr
 '
 
 test_done
diff --git a/t/t5533-push-cas.sh b/t/t5533-push-cas.sh
index cba26a872d..2e14aecaa2 100755
--- a/t/t5533-push-cas.sh
+++ b/t/t5533-push-cas.sh
@@ -69,7 +69,7 @@ test_expect_success 'push to update (protected)' '
 		cd dst &&
 		test_commit D &&
 		test_must_fail git push --force-with-lease=main:main origin main 2>err &&
-		grep "stale info" err
+		test_grep "stale info" err
 	) &&
 	git ls-remote . refs/heads/main >expect &&
 	git ls-remote src refs/heads/main >actual &&
@@ -82,7 +82,7 @@ test_expect_success 'push to update (protected, forced)' '
 		cd dst &&
 		test_commit D &&
 		git push --force --force-with-lease=main:main origin main 2>err &&
-		grep "forced update" err
+		test_grep "forced update" err
 	) &&
 	git ls-remote dst refs/heads/main >expect &&
 	git ls-remote src refs/heads/main >actual &&
@@ -147,7 +147,7 @@ test_expect_success 'push to update (allowed, tracking)' '
 		cd dst &&
 		test_commit D &&
 		git push --force-with-lease=main origin main 2>err &&
-		! grep "forced update" err
+		test_grep ! "forced update" err
 	) &&
 	git ls-remote dst refs/heads/main >expect &&
 	git ls-remote src refs/heads/main >actual &&
@@ -161,7 +161,7 @@ test_expect_success 'push to update (allowed even though no-ff)' '
 		git reset --hard HEAD^ &&
 		test_commit D &&
 		git push --force-with-lease=main origin main 2>err &&
-		grep "forced update" err
+		test_grep "forced update" err
 	) &&
 	git ls-remote dst refs/heads/main >expect &&
 	git ls-remote src refs/heads/main >actual &&
@@ -194,7 +194,7 @@ test_expect_success 'push to delete (allowed)' '
 	(
 		cd dst &&
 		git push --force-with-lease=main origin :main 2>err &&
-		grep deleted err
+		test_grep deleted err
 	) &&
 	git ls-remote src refs/heads/main >actual &&
 	test_must_be_empty actual
@@ -350,7 +350,7 @@ test_expect_success '"--force-if-includes" should be disabled for --force-with-l
 		remote_head="$(git rev-parse refs/remotes/origin/main)" &&
 		git fetch --all &&
 		test_must_fail git push --force-if-includes --force-with-lease="main:$remote_head" 2>err &&
-		grep "stale info" err
+		test_grep "stale info" err
 	) &&
 	git ls-remote dst refs/heads/main >actual.main &&
 	test_cmp expect.main actual.main
diff --git a/t/t5534-push-signed.sh b/t/t5534-push-signed.sh
index 2a782214ee..21f0262cbd 100755
--- a/t/t5534-push-signed.sh
+++ b/t/t5534-push-signed.sh
@@ -126,8 +126,8 @@ test_expect_success GPG 'signed push sends push certificate' '
 	noop=$(git rev-parse noop) &&
 	ff=$(git rev-parse ff) &&
 	noff=$(git rev-parse noff) &&
-	grep "$noop $ff refs/heads/ff" dst/push-cert &&
-	grep "$noop $noff refs/heads/noff" dst/push-cert &&
+	test_grep "$noop $ff refs/heads/ff" dst/push-cert &&
+	test_grep "$noop $noff refs/heads/noff" dst/push-cert &&
 	test_cmp expect dst/push-cert-status
 '
 
@@ -172,8 +172,8 @@ test_expect_success GPGSSH 'ssh signed push sends push certificate' '
 	noop=$(git rev-parse noop) &&
 	ff=$(git rev-parse ff) &&
 	noff=$(git rev-parse noff) &&
-	grep "$noop $ff refs/heads/ff" dst/push-cert &&
-	grep "$noop $noff refs/heads/noff" dst/push-cert &&
+	test_grep "$noop $ff refs/heads/ff" dst/push-cert &&
+	test_grep "$noop $noff refs/heads/noff" dst/push-cert &&
 	test_cmp expect dst/push-cert-status
 '
 
@@ -211,7 +211,7 @@ test_expect_success GPG 'inconsistent push options in signed push not allowed' '
 	git -C dst config receive.advertisepushoptions 1 &&
 	git receive-pack dst <push.tweak >out &&
 	git -C dst rev-parse ff &&
-	grep "inconsistent push options" out
+	test_grep "inconsistent push options" out
 '
 
 test_expect_success GPG 'fail without key and heed user.signingkey' '
@@ -257,8 +257,8 @@ test_expect_success GPG 'fail without key and heed user.signingkey' '
 	noop=$(git rev-parse noop) &&
 	ff=$(git rev-parse ff) &&
 	noff=$(git rev-parse noff) &&
-	grep "$noop $ff refs/heads/ff" dst/push-cert &&
-	grep "$noop $noff refs/heads/noff" dst/push-cert &&
+	test_grep "$noop $ff refs/heads/ff" dst/push-cert &&
+	test_grep "$noop $noff refs/heads/noff" dst/push-cert &&
 	test_cmp expect dst/push-cert-status
 '
 
@@ -309,8 +309,8 @@ test_expect_success GPGSM 'fail without key and heed user.signingkey x509' '
 	noop=$(git rev-parse noop) &&
 	ff=$(git rev-parse ff) &&
 	noff=$(git rev-parse noff) &&
-	grep "$noop $ff refs/heads/ff" dst/push-cert &&
-	grep "$noop $noff refs/heads/noff" dst/push-cert &&
+	test_grep "$noop $ff refs/heads/ff" dst/push-cert &&
+	test_grep "$noop $noff refs/heads/noff" dst/push-cert &&
 	test_cmp expect dst/push-cert-status
 '
 
@@ -362,8 +362,8 @@ test_expect_success GPGSSH 'fail without key and heed user.signingkey ssh' '
 	noop=$(git rev-parse noop) &&
 	ff=$(git rev-parse ff) &&
 	noff=$(git rev-parse noff) &&
-	grep "$noop $ff refs/heads/ff" dst/push-cert &&
-	grep "$noop $noff refs/heads/noff" dst/push-cert &&
+	test_grep "$noop $ff refs/heads/ff" dst/push-cert &&
+	test_grep "$noop $noff refs/heads/noff" dst/push-cert &&
 	test_cmp expect dst/push-cert-status
 '
 
diff --git a/t/t5537-fetch-shallow.sh b/t/t5537-fetch-shallow.sh
index 9982dd2aa6..f323ceebd2 100755
--- a/t/t5537-fetch-shallow.sh
+++ b/t/t5537-fetch-shallow.sh
@@ -244,7 +244,7 @@ test_expect_success '.git/shallow is edited by repack' '
 		origin "+refs/heads/*:refs/remotes/origin/*" &&
 	git -C shallow-client repack -adfl &&
 	test_must_fail git -C shallow-client rev-parse --verify $d^0 &&
-	! grep $d shallow-client/.git/shallow &&
+	test_grep ! $d shallow-client/.git/shallow &&
 
 	git -C shallow-server branch branch-orig $d &&
 	git -C shallow-client fetch --prune --depth=2 \
diff --git a/t/t5538-push-shallow.sh b/t/t5538-push-shallow.sh
index dc0e972943..afab456b32 100755
--- a/t/t5538-push-shallow.sh
+++ b/t/t5538-push-shallow.sh
@@ -65,7 +65,7 @@ test_expect_success 'push from shallow clone, with grafted roots' '
 	(
 	cd shallow2 &&
 	test_must_fail git push ../.git +main:refs/remotes/shallow2/main 2>err &&
-	grep "shallow2/main.*shallow update not allowed" err
+	test_grep "shallow2/main.*shallow update not allowed" err
 	) &&
 	test_must_fail git rev-parse shallow2/main &&
 	git fsck
diff --git a/t/t5539-fetch-http-shallow.sh b/t/t5539-fetch-http-shallow.sh
index 3ea75d34ca..44e6f609df 100755
--- a/t/t5539-fetch-http-shallow.sh
+++ b/t/t5539-fetch-http-shallow.sh
@@ -76,8 +76,8 @@ test_expect_success 'no shallow lines after receiving ACK ready' '
 		# might be able to run this test in all protocol versions.
 		GIT_TRACE_PACKET="$TRASH_DIRECTORY/trace" GIT_TEST_PROTOCOL_VERSION=0 \
 			git fetch --depth=2 &&
-		grep "fetch-pack< ACK .* ready" ../trace &&
-		! grep "fetch-pack> done" ../trace
+		test_grep "fetch-pack< ACK .* ready" ../trace &&
+		test_grep ! "fetch-pack> done" ../trace
 	)
 '
 
diff --git a/t/t5541-http-push-smart.sh b/t/t5541-http-push-smart.sh
index 538b603f03..8c34833027 100755
--- a/t/t5541-http-push-smart.sh
+++ b/t/t5541-http-push-smart.sh
@@ -56,8 +56,8 @@ test_expect_success 'push to remote repository (standard)' '
 	git commit -m path2 &&
 	HEAD=$(git rev-parse --verify HEAD) &&
 	GIT_TRACE_CURL=true git push -v -v 2>err &&
-	! grep "Expect: 100-continue" err &&
-	grep "POST git-receive-pack ([0-9]* bytes)" err &&
+	test_grep ! "Expect: 100-continue" err &&
+	test_grep "POST git-receive-pack ([0-9]* bytes)" err &&
 	(cd "$HTTPD_DOCUMENT_ROOT_PATH"/test_repo.git &&
 	 test $HEAD = $(git rev-parse --verify HEAD))
 '
@@ -84,7 +84,7 @@ test_expect_success 'push to remote repository (standard) with sending Accept-La
 	git commit -m path_lang &&
 	HEAD=$(git rev-parse --verify HEAD) &&
 	GIT_TRACE_CURL=true LANGUAGE="ko_KR.UTF-8" git push -v -v 2>err &&
-	! grep "Expect: 100-continue" err &&
+	test_grep ! "Expect: 100-continue" err &&
 
 	grep "=> Send header: Accept-Language:" err >err.language &&
 	test_cmp exp err.language
@@ -148,8 +148,8 @@ test_expect_success 'push fails for non-fast-forward refs unmatched by remote he
 	test_must_fail git push -v origin +main main:niam >output 2>&1'
 
 test_expect_success 'push fails for non-fast-forward refs unmatched by remote helper: remote output' '
-	grep "^ + [a-f0-9]*\.\.\.[a-f0-9]* *main -> main (forced update)$" output &&
-	grep "^ ! \[rejected\] *main -> niam (non-fast-forward)$" output
+	test_grep "^ + [a-f0-9]*\.\.\.[a-f0-9]* *main -> main (forced update)$" output &&
+	test_grep "^ ! \[rejected\] *main -> niam (non-fast-forward)$" output
 '
 
 test_expect_success 'push fails for non-fast-forward refs unmatched by remote helper: our output' '
@@ -163,7 +163,7 @@ test_expect_success 'push (chunked)' '
 	HEAD=$(git rev-parse --verify HEAD) &&
 	test_config http.postbuffer 4 &&
 	git push -v -v origin $BRANCH 2>err &&
-	grep "POST git-receive-pack (chunked)" err &&
+	test_grep "POST git-receive-pack (chunked)" err &&
 	(cd "$HTTPD_DOCUMENT_ROOT_PATH"/test_repo.git &&
 	 test $HEAD = $(git rev-parse --verify HEAD))
 '
@@ -215,15 +215,15 @@ test_expect_success 'push --atomic also prevents branch creation, reports collat
 	test_cmp expected actual &&
 
 	# the failed refs should be indicated to the user
-	grep "^ ! .*rejected.* main -> main" output &&
+	test_grep "^ ! .*rejected.* main -> main" output &&
 
 	# the collateral failure refs should be indicated to the user
-	grep "^ ! .*rejected.* atomic -> atomic .*atomic push failed" output &&
-	grep "^ ! .*rejected.* collateral -> collateral .*atomic push failed" output &&
+	test_grep "^ ! .*rejected.* atomic -> atomic .*atomic push failed" output &&
+	test_grep "^ ! .*rejected.* collateral -> collateral .*atomic push failed" output &&
 
 	# never report what we do not push
-	! grep "^ ! .*rejected.* atomic1 " output &&
-	! grep "^ ! .*rejected.* other " output
+	test_grep ! "^ ! .*rejected.* atomic1 " output &&
+	test_grep ! "^ ! .*rejected.* other " output
 '
 
 test_expect_success 'push --atomic fails on server-side errors' '
@@ -247,10 +247,10 @@ test_expect_success 'push --atomic fails on server-side errors' '
 	test_must_fail git -C "$d" show-ref --verify refs/heads/other &&
 
 	# the failed refs should be indicated to the user
-	grep "^ ! .*rejected.* other -> other .*atomic transaction failed" output &&
+	test_grep "^ ! .*rejected.* other -> other .*atomic transaction failed" output &&
 
 	# the collateral failure refs should be indicated to the user
-	grep "^ ! .*rejected.* atomic -> atomic .*atomic transaction failed" output
+	test_grep "^ ! .*rejected.* atomic -> atomic .*atomic transaction failed" output
 '
 
 test_expect_success 'push --all can push to empty repo' '
@@ -442,7 +442,7 @@ test_expect_success 'push status output scrubs password' '
 		"$HTTPD_URL_USER_PASS/smart/test_repo.git" \
 		+HEAD:scrub >status &&
 	# should have been scrubbed down to vanilla URL
-	grep "^To $HTTPD_URL/smart/test_repo.git" status
+	test_grep "^To $HTTPD_URL/smart/test_repo.git" status
 '
 
 test_expect_success 'clone/fetch scrubs password from reflogs' '
@@ -456,8 +456,8 @@ test_expect_success 'clone/fetch scrubs password from reflogs' '
 		+main:main &&
 	# should have been scrubbed down to vanilla URL
 	git log -g main >reflog &&
-	grep "$HTTPD_URL" reflog &&
-	! grep "$HTTPD_URL_USER_PASS" reflog
+	test_grep "$HTTPD_URL" reflog &&
+	test_grep ! "$HTTPD_URL_USER_PASS" reflog
 '
 
 test_expect_success 'Non-ASCII branch name can be used with --force-with-lease' '
diff --git a/t/t5544-pack-objects-hook.sh b/t/t5544-pack-objects-hook.sh
index 89147a052e..908d3b8ebe 100755
--- a/t/t5544-pack-objects-hook.sh
+++ b/t/t5544-pack-objects-hook.sh
@@ -27,7 +27,7 @@ test_expect_success 'hook runs via global config' '
 	clear_hook_results &&
 	test_config_global uploadpack.packObjectsHook ./hook &&
 	git clone --no-local . dst.git 2>stderr &&
-	grep "hook running" stderr
+	test_grep "hook running" stderr
 '
 
 test_expect_success 'hook outputs are sane' '
@@ -38,7 +38,7 @@ test_expect_success 'hook outputs are sane' '
 	# the full argument list or the exact pack contents, as it would make
 	# the test brittle. So just sanity check that we could replay
 	# the packing procedure.
-	grep "^git" .git/hook.args &&
+	test_grep "^git" .git/hook.args &&
 	$(cat .git/hook.args) <.git/hook.stdin >replay
 '
 
@@ -47,14 +47,14 @@ test_expect_success 'hook runs from -c config' '
 	git clone --no-local \
 	  -u "git -c uploadpack.packObjectsHook=./hook upload-pack" \
 	  . dst.git 2>stderr &&
-	grep "hook running" stderr
+	test_grep "hook running" stderr
 '
 
 test_expect_success 'hook does not run from repo config' '
 	clear_hook_results &&
 	test_config uploadpack.packObjectsHook "./hook" &&
 	git clone --no-local . dst.git 2>stderr &&
-	! grep "hook running" stderr &&
+	test_grep ! "hook running" stderr &&
 	test_path_is_missing .git/hook.args &&
 	test_path_is_missing .git/hook.stdin &&
 	test_path_is_missing .git/hook.stdout &&
@@ -62,7 +62,7 @@ test_expect_success 'hook does not run from repo config' '
 	# check that global config is used instead
 	test_config_global uploadpack.packObjectsHook ./hook &&
 	git clone --no-local . dst2.git 2>stderr &&
-	grep "hook running" stderr
+	test_grep "hook running" stderr
 '
 
 test_expect_success 'hook works with partial clone' '
@@ -72,7 +72,7 @@ test_expect_success 'hook works with partial clone' '
 	git clone --bare --no-local --filter=blob:none . dst.git &&
 	git -C dst.git rev-list --objects --missing=allow-any --no-object-names --all >objects &&
 	git -C dst.git cat-file --batch-check="%(objecttype)" <objects >types &&
-	! grep blob types
+	test_grep ! blob types
 '
 
 test_done
diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh
index b0080bf204..f00eeae48f 100755
--- a/t/t5550-http-fetch-dumb.sh
+++ b/t/t5550-http-fetch-dumb.sh
@@ -124,7 +124,7 @@ test_expect_success 'netrc authorized but forbidden credentials (fail on 403)' '
 	set_netrc 127.0.0.1 forbidden-user@host pass@host &&
 	test_must_fail git clone "$HTTPD_URL/auth/dumb/repo.git" clone-auth-netrc-403 2>err &&
 	expect_askpass none &&
-	grep "The requested URL returned error: 403" err
+	test_grep "The requested URL returned error: 403" err
 '
 
 test_expect_success 'http auth can use user/pass in URL' '
@@ -280,7 +280,7 @@ test_expect_success 'http-fetch --packfile' '
 		--index-pack-arg=--keep \
 		"$HTTPD_URL"/dumb/repo_pack.git/$p >out &&
 
-	grep -E "^keep.[0-9a-f]{16,}$" out &&
+	test_grep -E "^keep.[0-9a-f]{16,}$" out &&
 	cut -c6- out >packhash &&
 
 	# Ensure that the expected files are generated
diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index e236e526f0..76d3060fca 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -164,8 +164,8 @@ test_expect_success 'fetch changes via http' '
 
 test_expect_success 'used upload-pack service' '
 	strip_access_log >log &&
-	grep "GET  /smart/repo.git/info/refs?service=git-upload-pack HTTP/[0-9.]* 200" log &&
-	grep "POST /smart/repo.git/git-upload-pack HTTP/[0-9.]* 200" log
+	test_grep "GET  /smart/repo.git/info/refs?service=git-upload-pack HTTP/[0-9.]* 200" log &&
+	test_grep "POST /smart/repo.git/git-upload-pack HTTP/[0-9.]* 200" log
 '
 
 test_expect_success 'follow redirects (301)' '
@@ -264,8 +264,8 @@ test_expect_success 'GIT_TRACE_CURL redacts auth details' '
 
 	# Ensure that there is no "Basic" followed by a base64 string, but that
 	# the auth details are redacted
-	! grep -i "Authorization: Basic [0-9a-zA-Z+/]" trace &&
-	grep -i "Authorization: Basic <redacted>" trace
+	test_grep ! -i "Authorization: Basic [0-9a-zA-Z+/]" trace &&
+	test_grep -i "Authorization: Basic <redacted>" trace
 '
 
 test_expect_success 'GIT_CURL_VERBOSE redacts auth details' '
@@ -276,8 +276,8 @@ test_expect_success 'GIT_CURL_VERBOSE redacts auth details' '
 
 	# Ensure that there is no "Basic" followed by a base64 string, but that
 	# the auth details are redacted
-	! grep -i "Authorization: Basic [0-9a-zA-Z+/]" trace &&
-	grep -i "Authorization: Basic <redacted>" trace
+	test_grep ! -i "Authorization: Basic [0-9a-zA-Z+/]" trace &&
+	test_grep -i "Authorization: Basic <redacted>" trace
 '
 
 test_expect_success 'GIT_TRACE_CURL does not redact auth details if GIT_TRACE_REDACT=0' '
@@ -287,7 +287,7 @@ test_expect_success 'GIT_TRACE_CURL does not redact auth details if GIT_TRACE_RE
 		git clone --bare "$HTTPD_URL/auth/smart/repo.git" redact-auth &&
 	expect_askpass both user%40host &&
 
-	grep -i "Authorization: Basic [0-9a-zA-Z+/]" trace
+	test_grep -i "Authorization: Basic [0-9a-zA-Z+/]" trace
 '
 
 test_expect_success 'disable dumb http on server' '
@@ -418,7 +418,7 @@ test_expect_success 'large fetch-pack requests can be sent using chunked encodin
 		clone --bare "$HTTPD_URL/smart/repo.git" split.git 2>err &&
 	{
 		test_have_prereq HTTP2 ||
-		grep "^=> Send header: Transfer-Encoding: chunked" err
+		test_grep "^=> Send header: Transfer-Encoding: chunked" err
 	}
 '
 
@@ -553,10 +553,10 @@ test_expect_success 'cookies are redacted by default' '
 	GIT_TRACE_CURL=true \
 		git -c "http.cookieFile=$(pwd)/cookies" clone \
 		$HTTPD_URL/smart/repo.git clone 2>err &&
-	grep -i "Cookie:.*Foo=<redacted>" err &&
-	grep -i "Cookie:.*Bar=<redacted>" err &&
-	! grep -i "Cookie:.*Foo=1" err &&
-	! grep -i "Cookie:.*Bar=2" err
+	test_grep -i "Cookie:.*Foo=<redacted>" err &&
+	test_grep -i "Cookie:.*Bar=<redacted>" err &&
+	test_grep ! -i "Cookie:.*Foo=1" err &&
+	test_grep ! -i "Cookie:.*Bar=2" err
 '
 
 test_expect_success 'empty values of cookies are also redacted' '
@@ -565,7 +565,7 @@ test_expect_success 'empty values of cookies are also redacted' '
 	GIT_TRACE_CURL=true \
 		git -c "http.cookieFile=$(pwd)/cookies" clone \
 		$HTTPD_URL/smart/repo.git clone 2>err &&
-	grep -i "Cookie:.*Foo=<redacted>" err
+	test_grep -i "Cookie:.*Foo=<redacted>" err
 '
 
 test_expect_success 'GIT_TRACE_REDACT=0 disables cookie redaction' '
@@ -575,20 +575,20 @@ test_expect_success 'GIT_TRACE_REDACT=0 disables cookie redaction' '
 	GIT_TRACE_REDACT=0 GIT_TRACE_CURL=true \
 		git -c "http.cookieFile=$(pwd)/cookies" clone \
 		$HTTPD_URL/smart/repo.git clone 2>err &&
-	grep -i "Cookie:.*Foo=1" err &&
-	grep -i "Cookie:.*Bar=2" err
+	test_grep -i "Cookie:.*Foo=1" err &&
+	test_grep -i "Cookie:.*Bar=2" err
 '
 
 test_expect_success 'GIT_TRACE_CURL_NO_DATA prevents data from being traced' '
 	rm -rf clone &&
 	GIT_TRACE_CURL=true \
 		git clone $HTTPD_URL/smart/repo.git clone 2>err &&
-	grep "=> Send data" err &&
+	test_grep "=> Send data" err &&
 
 	rm -rf clone &&
 	GIT_TRACE_CURL=true GIT_TRACE_CURL_NO_DATA=1 \
 		git clone $HTTPD_URL/smart/repo.git clone 2>err &&
-	! grep "=> Send data" err
+	test_grep ! "=> Send data" err
 '
 
 test_expect_success 'server-side error detected' '
@@ -643,7 +643,7 @@ test_expect_success 'client falls back from v2 to v0 to match server' '
 	git clone $HTTPD_URL/smart_v0/repo.git repo-v0 &&
 	# check for v0; there the HEAD symref is communicated in the capability
 	# line; v2 uses a different syntax on each ref advertisement line
-	grep symref=HEAD:refs/heads/ trace
+	test_grep symref=HEAD:refs/heads/ trace
 '
 
 test_expect_success 'create empty http-accessible SHA-256 repository' '
@@ -691,7 +691,7 @@ test_expect_success 'clone warns or fails when using username:password' '
 
 	git -c transfer.credentialsInUrl=allow \
 		clone $url_userpass attempt1 2>err &&
-	! grep "$message" err &&
+	test_grep ! "$message" err &&
 
 	git -c transfer.credentialsInUrl=warn \
 		clone $url_userpass attempt2 2>err &&
@@ -720,12 +720,12 @@ test_expect_success 'clone does not detect username:password when it is https://
 	esac &&
 
 	git -c transfer.credentialsInUrl=warn clone $url_user attempt1 2>err &&
-	! grep "uses plaintext credentials" err
+	test_grep ! "uses plaintext credentials" err
 '
 
 test_expect_success 'fetch warns or fails when using username:password' '
 	git -c transfer.credentialsInUrl=allow fetch $url_userpass 2>err &&
-	! grep "$message" err &&
+	test_grep ! "$message" err &&
 
 	git -c transfer.credentialsInUrl=warn fetch $url_userpass 2>err &&
 	grep "warning: $message" err >warnings &&
@@ -745,7 +745,7 @@ test_expect_success 'fetch warns or fails when using username:password' '
 
 test_expect_success 'push warns or fails when using username:password' '
 	git -c transfer.credentialsInUrl=allow push $url_userpass 2>err &&
-	! grep "$message" err &&
+	test_grep ! "$message" err &&
 
 	git -c transfer.credentialsInUrl=warn push $url_userpass 2>err &&
 	grep "warning: $message" err >warnings &&
@@ -762,7 +762,7 @@ test_expect_success 'no empty path components' '
 	git clone $HTTPD_URL/smart/repo.git/ clone-with-slash &&
 
 	strip_access_log >log &&
-	! grep "//" log
+	test_grep ! "//" log
 '
 
 test_expect_success 'tag following always works over v0 http' '
diff --git a/t/t5552-skipping-fetch-negotiator.sh b/t/t5552-skipping-fetch-negotiator.sh
index eeddb85b1d..96e224168e 100755
--- a/t/t5552-skipping-fetch-negotiator.sh
+++ b/t/t5552-skipping-fetch-negotiator.sh
@@ -201,7 +201,7 @@ test_expect_success 'do not send "have" with ancestors of commits that server AC
 		export GIT_TEST_PROTOCOL_VERSION &&
 		trace_fetch client "$(pwd)/server" to_fetch
 	) &&
-	grep "  fetch" trace &&
+	test_grep "  fetch" trace &&
 
 	# fetch-pack sends 2 requests each containing 16 "have" lines before
 	# processing the first response. In these 2 requests, 4 commits from
@@ -211,8 +211,8 @@ test_expect_success 'do not send "have" with ancestors of commits that server AC
 
 	# While fetch-pack is processing the first response, it should read that
 	# the server ACKs b1.c19 and b1.c17.
-	grep "fetch< ACK $(git -C client rev-parse b1.c19) common" trace &&
-	grep "fetch< ACK $(git -C client rev-parse b1.c17) common" trace &&
+	test_grep "fetch< ACK $(git -C client rev-parse b1.c19) common" trace &&
+	test_grep "fetch< ACK $(git -C client rev-parse b1.c17) common" trace &&
 
 	# fetch-pack should thus not send any more commits in the b1 branch, but
 	# should still send the others (in this test, just check b2).
diff --git a/t/t5554-noop-fetch-negotiator.sh b/t/t5554-noop-fetch-negotiator.sh
index 17e73b606d..d50ffe55b6 100755
--- a/t/t5554-noop-fetch-negotiator.sh
+++ b/t/t5554-noop-fetch-negotiator.sh
@@ -16,8 +16,8 @@ test_expect_success 'noop negotiator does not emit any "have"' '
 	test_config -C client fetch.negotiationalgorithm noop &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch "$(pwd)/server" &&
 
-	! grep "fetch> have" trace &&
-	grep "fetch> done" trace
+	test_grep ! "fetch> have" trace &&
+	test_grep "fetch> done" trace
 '
 
 test_done
diff --git a/t/t5557-http-get.sh b/t/t5557-http-get.sh
index 67fcc23f11..e8ffe3f8e9 100755
--- a/t/t5557-http-get.sh
+++ b/t/t5557-http-get.sh
@@ -18,7 +18,7 @@ test_expect_success 'get by URL: 404' '
 
 	test_must_fail git remote-http $url <input 2>err &&
 	test_path_is_missing file1 &&
-	grep "failed to download file at URL" err
+	test_grep "failed to download file at URL" err
 '
 
 test_expect_success 'get by URL: 200' '
diff --git a/t/t5558-clone-bundle-uri.sh b/t/t5558-clone-bundle-uri.sh
index 7a0943bd36..0d5be0d56e 100755
--- a/t/t5558-clone-bundle-uri.sh
+++ b/t/t5558-clone-bundle-uri.sh
@@ -8,14 +8,14 @@ test_description='test fetching bundles with --bundle-uri'
 test_expect_success 'fail to clone from non-existent file' '
 	test_when_finished rm -rf test &&
 	git clone --bundle-uri="$(pwd)/does-not-exist" . test 2>err &&
-	grep "failed to download bundle from URI" err
+	test_grep "failed to download bundle from URI" err
 '
 
 test_expect_success 'fail to clone from non-bundle file' '
 	test_when_finished rm -rf test &&
 	echo bogus >bogus &&
 	git clone --bundle-uri="$(pwd)/bogus" . test 2>err &&
-	grep "is not a bundle" err
+	test_grep "is not a bundle" err
 '
 
 test_expect_success 'create bundle' '
@@ -197,7 +197,7 @@ test_expect_success 'clone bundle list (file, no heuristic)' '
 
 	git clone --bundle-uri="file://$(pwd)/bundle-list" \
 		clone-from clone-list-file 2>err &&
-	! grep "Repository lacks these prerequisite commits" err &&
+	test_grep ! "Repository lacks these prerequisite commits" err &&
 
 	git -C clone-from for-each-ref --format="%(objectname)" >oids &&
 	git -C clone-list-file cat-file --batch-check <oids &&
@@ -242,9 +242,9 @@ test_expect_success 'clone bundle list (file, all mode, some failures)' '
 	GIT_TRACE2_PERF=1 \
 	git clone --bundle-uri="file://$(pwd)/bundle-list" \
 		clone-from clone-all-some 2>err &&
-	! grep "Repository lacks these prerequisite commits" err &&
-	! grep "fatal" err &&
-	grep "warning: failed to download bundle from URI" err &&
+	test_grep ! "Repository lacks these prerequisite commits" err &&
+	test_grep ! "fatal" err &&
+	test_grep "warning: failed to download bundle from URI" err &&
 
 	git -C clone-from for-each-ref --format="%(objectname)" >oids &&
 	git -C clone-all-some cat-file --batch-check <oids &&
@@ -275,15 +275,15 @@ test_expect_success 'clone bundle list (file, all mode, all failures)' '
 
 	git clone --bundle-uri="file://$(pwd)/bundle-list" \
 		clone-from clone-all-fail 2>err &&
-	! grep "Repository lacks these prerequisite commits" err &&
-	! grep "fatal" err &&
-	grep "warning: failed to download bundle from URI" err &&
+	test_grep ! "Repository lacks these prerequisite commits" err &&
+	test_grep ! "fatal" err &&
+	test_grep "warning: failed to download bundle from URI" err &&
 
 	git -C clone-from for-each-ref --format="%(objectname)" >oids &&
 	git -C clone-all-fail cat-file --batch-check <oids &&
 
 	git -C clone-all-fail for-each-ref --format="%(refname)" >refs &&
-	! grep "refs/bundles/heads/" refs
+	test_grep ! "refs/bundles/heads/" refs
 '
 
 test_expect_success 'clone bundle list (file, any mode)' '
@@ -306,7 +306,7 @@ test_expect_success 'clone bundle list (file, any mode)' '
 
 	git clone --bundle-uri="file://$(pwd)/bundle-list" \
 		clone-from clone-any-file 2>err &&
-	! grep "Repository lacks these prerequisite commits" err &&
+	test_grep ! "Repository lacks these prerequisite commits" err &&
 
 	git -C clone-from for-each-ref --format="%(objectname)" >oids &&
 	git -C clone-any-file cat-file --batch-check <oids &&
@@ -336,14 +336,14 @@ test_expect_success 'clone bundle list (file, any mode, all failures)' '
 
 	git clone --bundle-uri="file://$(pwd)/bundle-list" \
 		clone-from clone-any-fail 2>err &&
-	! grep "fatal" err &&
-	grep "warning: failed to download bundle from URI" err &&
+	test_grep ! "fatal" err &&
+	test_grep "warning: failed to download bundle from URI" err &&
 
 	git -C clone-from for-each-ref --format="%(objectname)" >oids &&
 	git -C clone-any-fail cat-file --batch-check <oids &&
 
 	git -C clone-any-fail for-each-ref --format="%(refname)" >refs &&
-	! grep "refs/bundles/heads/" refs
+	test_grep ! "refs/bundles/heads/" refs
 '
 
 test_expect_success 'negotiation: bundle with part of wanted commits' '
@@ -477,14 +477,14 @@ start_httpd
 test_expect_success 'fail to fetch from non-existent HTTP URL' '
 	test_when_finished rm -rf test &&
 	git clone --bundle-uri="$HTTPD_URL/does-not-exist" . test 2>err &&
-	grep "failed to download bundle from URI" err
+	test_grep "failed to download bundle from URI" err
 '
 
 test_expect_success 'fail to fetch from non-bundle HTTP URL' '
 	test_when_finished rm -rf test &&
 	echo bogus >"$HTTPD_DOCUMENT_ROOT_PATH/bogus" &&
 	git clone --bundle-uri="$HTTPD_URL/bogus" . test 2>err &&
-	grep "is not a bundle" err
+	test_grep "is not a bundle" err
 '
 
 test_expect_success 'clone HTTP bundle' '
@@ -536,7 +536,7 @@ test_expect_success 'clone bundle list (HTTP, no heuristic)' '
 	GIT_TRACE2_EVENT="$(pwd)/trace-clone.txt" \
 		git clone --bundle-uri="$HTTPD_URL/bundle-list" \
 		clone-from clone-list-http  2>err &&
-	! grep "Repository lacks these prerequisite commits" err &&
+	test_grep ! "Repository lacks these prerequisite commits" err &&
 
 	git -C clone-from for-each-ref --format="%(objectname)" >oids &&
 	git -C clone-list-http cat-file --batch-check <oids &&
@@ -576,8 +576,8 @@ test_expect_success 'clone bundle list (HTTP, any mode)' '
 
 	git clone --bundle-uri="$HTTPD_URL/bundle-list" \
 		clone-from clone-any-http 2>err &&
-	! grep "fatal" err &&
-	grep "warning: failed to download bundle from URI" err &&
+	test_grep ! "fatal" err &&
+	test_grep "warning: failed to download bundle from URI" err &&
 
 	git -C clone-from for-each-ref --format="%(objectname)" >oids &&
 	git -C clone-any-http cat-file --batch-check <oids &&
diff --git a/t/t5562-http-backend-content-length.sh b/t/t5562-http-backend-content-length.sh
index b6ee06f5c8..59c6a50dd2 100755
--- a/t/t5562-http-backend-content-length.sh
+++ b/t/t5562-http-backend-content-length.sh
@@ -163,7 +163,7 @@ test_expect_success 'CONTENT_LENGTH overflow ssite_t' '
 		REQUEST_METHOD=POST \
 		CONTENT_LENGTH="$NOT_FIT_IN_SSIZE" \
 		git http-backend </dev/null >/dev/null 2>err &&
-	grep "fatal:.*CONTENT_LENGTH" err
+	test_grep "fatal:.*CONTENT_LENGTH" err
 '
 
 test_expect_success 'empty CONTENT_LENGTH' '
diff --git a/t/t5564-http-proxy.sh b/t/t5564-http-proxy.sh
index 817cd1f984..866e2b4e93 100755
--- a/t/t5564-http-proxy.sh
+++ b/t/t5564-http-proxy.sh
@@ -20,14 +20,14 @@ setup_askpass_helper
 test_expect_success 'proxy requires password' '
 	test_config_global http.proxy $HTTPD_DEST &&
 	test_must_fail git clone $HTTPD_URL/smart/repo.git 2>err &&
-	grep "error.*407" err
+	test_grep "error.*407" err
 '
 
 test_expect_success 'clone through proxy with auth' '
 	test_when_finished "rm -rf clone" &&
 	test_config_global http.proxy http://proxuser:proxpass@$HTTPD_DEST &&
 	GIT_TRACE_CURL=$PWD/trace git clone $HTTPD_URL/smart/repo.git clone &&
-	grep -i "Proxy-Authorization: Basic <redacted>" trace
+	test_grep -i "Proxy-Authorization: Basic <redacted>" trace
 '
 
 test_expect_success 'clone can prompt for proxy password' '
@@ -82,7 +82,7 @@ test_expect_success SOCKS_PROXY 'clone via Unix socket' '
 			GIT_TRACE_CURL=$PWD/trace \
 			GIT_TRACE_CURL_COMPONENTS=socks \
 			git clone "$HTTPD_URL/smart/repo.git" clone 2>err &&
-			grep -i "SOCKS4 request granted" trace
+			test_grep -i "SOCKS4 request granted" trace
 		} ||
 		old_libcurl_error err
 	}
@@ -90,14 +90,14 @@ test_expect_success SOCKS_PROXY 'clone via Unix socket' '
 
 test_expect_success 'Unix socket requires socks*:' - <<\EOT
 	! git clone -c http.proxy=localhost/path https://example.com/repo.git 2>err && {
-		grep -Fx "fatal: Invalid proxy URL 'localhost/path': only SOCKS proxies support paths" err ||
+		test_grep -Fx "fatal: Invalid proxy URL 'localhost/path': only SOCKS proxies support paths" err ||
 		old_libcurl_error err
 	}
 EOT
 
 test_expect_success 'Unix socket requires localhost' - <<\EOT
 	! git clone -c http.proxy=socks4://127.0.0.1/path https://example.com/repo.git 2>err && {
-		grep -Fx "fatal: Invalid proxy URL 'socks4://127.0.0.1/path': host must be localhost if a path is present" err ||
+		test_grep -Fx "fatal: Invalid proxy URL 'socks4://127.0.0.1/path': host must be localhost if a path is present" err ||
 		old_libcurl_error err
 	}
 EOT
diff --git a/t/t5581-http-curl-verbose.sh b/t/t5581-http-curl-verbose.sh
index cded79c16b..6788cf8171 100755
--- a/t/t5581-http-curl-verbose.sh
+++ b/t/t5581-http-curl-verbose.sh
@@ -23,7 +23,7 @@ test_expect_success 'failure in git-upload-pack is shown' '
 	test_might_fail env GIT_CURL_VERBOSE=1 \
 		git clone "$HTTPD_URL/error_git_upload_pack/smart/repo.git" \
 		2>curl_log &&
-	grep "<= Recv header: HTTP/1.1 500 Intentional Breakage" curl_log
+	test_grep "<= Recv header: HTTP/1.1 500 Intentional Breakage" curl_log
 '
 
 test_done
diff --git a/t/t5583-push-branches.sh b/t/t5583-push-branches.sh
index e7e1b6dab6..1ccfaee75a 100755
--- a/t/t5583-push-branches.sh
+++ b/t/t5583-push-branches.sh
@@ -60,21 +60,21 @@ test_expect_success '--all or --branches can not be combined with refspecs' '
 	test_must_fail git push remote-1 --all main >actual.all 2>&1 &&
 	test_must_fail git push remote-1 --branches main >actual.branches 2>&1 &&
 	test_cmp actual.all actual.branches &&
-	grep "be combined with refspecs" actual.all
+	test_grep "be combined with refspecs" actual.all
 '
 
 test_expect_success '--all or --branches can not be combined with --mirror' '
 	test_must_fail git push remote-1 --all --mirror >actual.all 2>&1 &&
 	test_must_fail git push remote-1 --branches --mirror >actual.branches 2>&1 &&
 	test_cmp actual.all actual.branches &&
-	grep "cannot be used together" actual.all
+	test_grep "cannot be used together" actual.all
 '
 
 test_expect_success '--all or --branches can not be combined with --tags' '
 	test_must_fail git push remote-1 --all --tags >actual.all 2>&1 &&
 	test_must_fail git push remote-1 --branches --tags >actual.branches 2>&1 &&
 	test_cmp actual.all actual.branches &&
-	grep "cannot be used together" actual.all
+	test_grep "cannot be used together" actual.all
 '
 
 
@@ -82,7 +82,7 @@ test_expect_success '--all or --branches can not be combined with --delete' '
 	test_must_fail git push remote-1 --all --delete >actual.all 2>&1 &&
 	test_must_fail git push remote-1 --branches --delete >actual.branches 2>&1 &&
 	test_cmp actual.all actual.branches &&
-	grep "cannot be used together" actual.all
+	test_grep "cannot be used together" actual.all
 '
 
 test_expect_success '--all or --branches combines with --follow-tags have same behavior' '
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 3dd229c186..b6167582a1 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -159,8 +159,8 @@ test_expect_success 'clone --mirror does not repeat tags' '
 	git clone --mirror src mirror2 &&
 	(cd mirror2 &&
 	 git show-ref 2> clone.err > clone.out) &&
-	! grep Duplicate mirror2/clone.err &&
-	grep some-tag mirror2/clone.out
+	test_grep ! Duplicate mirror2/clone.err &&
+	test_grep some-tag mirror2/clone.out
 
 '
 
@@ -224,12 +224,12 @@ test_expect_success 'clone a void' '
 		cd src-0 && git init
 	) &&
 	git clone "file://$(pwd)/src-0" target-6 2>err-6 &&
-	! grep "fatal:" err-6 &&
+	test_grep ! "fatal:" err-6 &&
 	(
 		cd src-0 && test_commit A
 	) &&
 	git clone "file://$(pwd)/src-0" target-7 2>err-7 &&
-	! grep "fatal:" err-7 &&
+	test_grep ! "fatal:" err-7 &&
 	# There is no reason to insist they are bit-for-bit
 	# identical, but this test should suffice for now.
 	test_cmp target-6/.git/config target-7/.git/config
@@ -298,22 +298,22 @@ test_expect_success 'clone separate gitdir where target already exists' '
 	rm -rf dst &&
 	echo foo=bar >>realgitdir/config &&
 	test_must_fail git clone --separate-git-dir realgitdir src dst &&
-	grep foo=bar realgitdir/config
+	test_grep foo=bar realgitdir/config
 '
 
 test_expect_success 'clone --reference from original' '
 	git clone --shared --bare src src-1 &&
 	git clone --bare src src-2 &&
 	git clone --reference=src-2 --bare src-1 target-8 &&
-	grep /src-2/ target-8/objects/info/alternates
+	test_grep /src-2/ target-8/objects/info/alternates
 '
 
 test_expect_success 'clone with more than one --reference' '
 	git clone --bare src src-3 &&
 	git clone --bare src src-4 &&
 	git clone --reference=src-3 --reference=src-4 src target-9 &&
-	grep /src-3/ target-9/.git/objects/info/alternates &&
-	grep /src-4/ target-9/.git/objects/info/alternates
+	test_grep /src-3/ target-9/.git/objects/info/alternates &&
+	test_grep /src-4/ target-9/.git/objects/info/alternates
 '
 
 test_expect_success 'clone from original with relative alternate' '
@@ -321,7 +321,7 @@ test_expect_success 'clone from original with relative alternate' '
 	git clone --bare src nest/src-5 &&
 	echo ../../../src/.git/objects >nest/src-5/objects/info/alternates &&
 	git clone --bare nest/src-5 target-10 &&
-	grep /src/\\.git/objects target-10/objects/info/alternates
+	test_grep /src/\\.git/objects target-10/objects/info/alternates
 '
 
 test_expect_success 'clone checking out a tag' '
@@ -663,8 +663,8 @@ test_expect_success PERL_TEST_HELPERS 'clone on case-insensitive fs' '
 '
 
 test_expect_success PERL_TEST_HELPERS,CASE_INSENSITIVE_FS 'colliding file detection' '
-	grep X icasefs/warning &&
-	grep x icasefs/warning &&
+	test_grep X icasefs/warning &&
+	test_grep x icasefs/warning &&
 	test_grep "the following paths have collided" icasefs/warning
 '
 
@@ -857,7 +857,7 @@ test_expect_success 'auto-discover bundle URI from HTTP clone' '
 	cat >pattern <<-EOF &&
 	"event":"child_start".*"argv":\["git-remote-https","$HTTPD_URL/everything.bundle"\]
 	EOF
-	grep -f pattern trace.txt
+	test_grep -f pattern trace.txt
 '
 
 test_expect_success 'auto-discover multiple bundles from HTTP clone' '
@@ -888,11 +888,11 @@ test_expect_success 'auto-discover multiple bundles from HTTP clone' '
 	cat >pattern <<-EOF &&
 	"event":"child_start".*"argv":\["git-remote-https","$HTTPD_URL/everything.bundle"\]
 	EOF
-	grep -f pattern trace.txt &&
+	test_grep -f pattern trace.txt &&
 	cat >pattern <<-EOF &&
 	"event":"child_start".*"argv":\["git-remote-https","$HTTPD_URL/new.bundle"\]
 	EOF
-	grep -f pattern trace.txt
+	test_grep -f pattern trace.txt
 '
 
 test_expect_success 'auto-discover multiple bundles from HTTP clone: creationToken heuristic' '
diff --git a/t/t5604-clone-reference.sh b/t/t5604-clone-reference.sh
index c232ab8c15..39a0c318df 100755
--- a/t/t5604-clone-reference.sh
+++ b/t/t5604-clone-reference.sh
@@ -65,7 +65,7 @@ test_expect_success 'cloning with reference (no -l -s)' '
 
 test_expect_success 'fetched no objects' '
 	test -s "$U.D" &&
-	! grep " want" "$U.D"
+	test_grep ! " want" "$U.D"
 '
 
 test_expect_success 'existence of info/alternates' '
@@ -157,9 +157,9 @@ test_expect_success 'fetch with incomplete alternates' '
 	) &&
 	main_object=$(git -C A rev-parse --verify refs/heads/main) &&
 	test -s "$U.K" &&
-	! grep " want $main_object" "$U.K" &&
+	test_grep ! " want $main_object" "$U.K" &&
 	tag_object=$(git -C A rev-parse --verify refs/tags/foo) &&
-	! grep " want $tag_object" "$U.K"
+	test_grep ! " want $tag_object" "$U.K"
 '
 
 test_expect_success 'clone using repo with gitfile as a reference' '
@@ -357,7 +357,7 @@ test_expect_success SYMLINKS 'clone repo with symlinked objects directory' '
 	test_must_fail git clone --local malicious clone 2>err &&
 
 	test_path_is_missing clone &&
-	grep "is a symlink, refusing to clone with --local" err
+	test_grep "is a symlink, refusing to clone with --local" err
 '
 
 test_expect_success 'dissociate from repo with commit graph' '
diff --git a/t/t5605-clone-local.sh b/t/t5605-clone-local.sh
index 2397f8fa61..156362f145 100755
--- a/t/t5605-clone-local.sh
+++ b/t/t5605-clone-local.sh
@@ -172,7 +172,7 @@ test_expect_success REFFILES 'local clone from repo with corrupt refs fails grac
 	echo a >corrupt/.git/refs/heads/topic &&
 
 	test_must_fail git clone corrupt working 2>err &&
-	grep "has neither a valid OID nor a target" err
+	test_grep "has neither a valid OID nor a target" err
 '
 
 test_done
diff --git a/t/t5606-clone-options.sh b/t/t5606-clone-options.sh
index 8a15237736..1b48da496b 100755
--- a/t/t5606-clone-options.sh
+++ b/t/t5606-clone-options.sh
@@ -63,7 +63,7 @@ test_expect_success 'disallows --bundle-uri with shallow options' '
 	for option in --depth=1 --shallow-since=01-01-2000 --shallow-exclude=HEAD
 	do
 		test_must_fail git clone --bundle-uri=bundle $option from to 2>err &&
-		grep "bundle-uri.* cannot be used together" err || return 1
+		test_grep "bundle-uri.* cannot be used together" err || return 1
 	done
 '
 
@@ -147,7 +147,7 @@ test_expect_success 'prefers --origin over -c config' '
 test_expect_success 'redirected clone does not show progress' '
 
 	git clone "file://$(pwd)/parent" clone-redirected >out 2>err &&
-	! grep % err &&
+	test_grep ! % err &&
 	test_grep ! "Checking connectivity" err
 
 '
@@ -156,7 +156,7 @@ test_expect_success 'redirected clone -v does show progress' '
 
 	git clone --progress "file://$(pwd)/parent" clone-redirected-progress \
 		>out 2>err &&
-	grep % err
+	test_grep % err
 
 '
 
diff --git a/t/t5612-clone-refspec.sh b/t/t5612-clone-refspec.sh
index 3126cfd7e9..dd1fe0abb4 100755
--- a/t/t5612-clone-refspec.sh
+++ b/t/t5612-clone-refspec.sh
@@ -97,7 +97,7 @@ test_expect_success 'by default no tags will be kept updated' '
 test_expect_success 'clone with --no-tags' '
 	(
 		cd dir_all_no_tags &&
-		grep tagOpt .git/config &&
+		test_grep tagOpt .git/config &&
 		git fetch &&
 		git for-each-ref refs/tags >../actual
 	) &&
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 1c2805acca..ddbf2b72c6 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -60,8 +60,8 @@ test_expect_success 'verify that .promisor file contains refs fetched' '
 	ls pc1/.git/objects/pack/pack-*.promisor >promisorlist &&
 	test_line_count = 1 promisorlist &&
 	git -C srv.bare rev-parse --verify HEAD >headhash &&
-	grep "$(cat headhash) HEAD" $(cat promisorlist) &&
-	grep "$(cat headhash) refs/heads/main" $(cat promisorlist)
+	test_grep "$(cat headhash) HEAD" $(cat promisorlist) &&
+	test_grep "$(cat headhash) refs/heads/main" $(cat promisorlist)
 '
 
 # checkout main to force dynamic object fetch of blobs at HEAD.
@@ -230,8 +230,8 @@ test_expect_success 'fetch --refetch triggers repacking' '
 	GIT_TRACE2_EVENT="$PWD/trace1.event" \
 	git -C pc1 fetch --refetch origin &&
 	test_subcommand git maintenance run --auto --no-quiet --no-detach <trace1.event &&
-	grep \"param\":\"gc.autopacklimit\",\"value\":\"1\" trace1.event &&
-	grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"-1\" trace1.event &&
+	test_grep \"param\":\"gc.autopacklimit\",\"value\":\"1\" trace1.event &&
+	test_grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"-1\" trace1.event &&
 
 	GIT_TRACE2_EVENT="$PWD/trace2.event" \
 	git -c protocol.version=0 \
@@ -239,8 +239,8 @@ test_expect_success 'fetch --refetch triggers repacking' '
 		-c maintenance.incremental-repack.auto=1234 \
 		-C pc1 fetch --refetch origin &&
 	test_subcommand git maintenance run --auto --no-quiet --no-detach <trace2.event &&
-	grep \"param\":\"gc.autopacklimit\",\"value\":\"0\" trace2.event &&
-	grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"-1\" trace2.event &&
+	test_grep \"param\":\"gc.autopacklimit\",\"value\":\"0\" trace2.event &&
+	test_grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"-1\" trace2.event &&
 
 	GIT_TRACE2_EVENT="$PWD/trace3.event" \
 	git -c protocol.version=0 \
@@ -248,8 +248,8 @@ test_expect_success 'fetch --refetch triggers repacking' '
 		-c maintenance.incremental-repack.auto=0 \
 		-C pc1 fetch --refetch origin &&
 	test_subcommand git maintenance run --auto --no-quiet --no-detach <trace3.event &&
-	grep \"param\":\"gc.autopacklimit\",\"value\":\"1\" trace3.event &&
-	grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"0\" trace3.event
+	test_grep \"param\":\"gc.autopacklimit\",\"value\":\"1\" trace3.event &&
+	test_grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"0\" trace3.event
 '
 
 test_expect_success 'partial clone with transfer.fsckobjects=1 works with submodules' '
@@ -284,7 +284,7 @@ test_expect_success 'partial clone with transfer.fsckobjects=1 uses index-pack -
 
 	GIT_TRACE="$(pwd)/trace" git -c transfer.fsckobjects=1 \
 		clone --filter="blob:none" "file://$(pwd)/src" dst &&
-	grep "git index-pack.*--fsck-objects" trace
+	test_grep "git index-pack.*--fsck-objects" trace
 '
 
 test_expect_success 'use fsck before and after manually fetching a missing subtree' '
@@ -312,7 +312,7 @@ test_expect_success 'use fsck before and after manually fetching a missing subtr
 
 	# Auto-fetch a tree with cat-file.
 	git -C dst cat-file -p $SUBTREE >tree_contents &&
-	grep file.txt tree_contents &&
+	test_grep file.txt tree_contents &&
 
 	# fsck still works after an auto-fetch of a tree.
 	git -C dst fsck &&
@@ -333,14 +333,14 @@ test_expect_success 'implicitly construct combine: filter with repeated flags' '
 	GIT_TRACE=$(pwd)/trace git clone --bare \
 		--filter=blob:none --filter=tree:1 \
 		"file://$(pwd)/srv.bare" pc2 &&
-	grep "trace:.* git pack-objects .*--filter=combine:blob:none+tree:1" \
+	test_grep "trace:.* git pack-objects .*--filter=combine:blob:none+tree:1" \
 		trace &&
 	git -C pc2 rev-list --objects --missing=allow-any HEAD >objects &&
 
 	# We should have gotten some root trees.
-	grep " $" objects &&
+	test_grep " $" objects &&
 	# Should not have gotten any non-root trees or blobs.
-	! grep " ." objects &&
+	test_grep ! " ." objects &&
 
 	xargs -n 1 git -C pc2 cat-file -t <objects >types &&
 	sort -u types >unique_types.actual &&
@@ -409,7 +409,7 @@ test_expect_success 'partial clone fetches blobs pointed to by refs even if norm
 	git -C src tag myblob "$BLOB" &&
 
 	git clone --filter="blob:none" "file://$(pwd)/src" dst 2>err &&
-	! grep "does not point to a valid object" err &&
+	test_grep ! "does not point to a valid object" err &&
 	git -C dst fsck
 '
 
@@ -424,10 +424,10 @@ test_expect_success 'fetch what is specified on CLI even if already promised' '
 
 	git clone --bare --filter=blob:none "file://$(pwd)/src" dst.git &&
 	git -C dst.git rev-list --objects --quiet --missing=print HEAD >missing_before &&
-	grep "?$(cat blob)" missing_before &&
+	test_grep "?$(cat blob)" missing_before &&
 	git -C dst.git fetch origin $(cat blob) &&
 	git -C dst.git rev-list --objects --quiet --missing=print HEAD >missing_after &&
-	! grep "?$(cat blob)" missing_after
+	test_grep ! "?$(cat blob)" missing_after
 '
 
 test_expect_success 'setup src repo for sparse filter' '
@@ -449,8 +449,8 @@ test_expect_success 'partial clone with sparse filter succeeds' '
 	(
 		cd dst.git &&
 		git rev-list --objects --missing=print HEAD >out &&
-		grep "^$(git rev-parse HEAD:one.t)" out &&
-		grep "^?$(git rev-parse HEAD:two.t)" out
+		test_grep "^$(git rev-parse HEAD:one.t)" out &&
+		test_grep "^?$(git rev-parse HEAD:two.t)" out
 	)
 '
 
@@ -521,7 +521,7 @@ test_expect_success 'fetch lazy-fetches only to resolve deltas' '
 	# Verify the assumption that the client needed to fetch the delta base
 	# to resolve the delta.
 	git -C server rev-parse HEAD~1^{tree} >hash &&
-	grep "want $(cat hash)" trace
+	test_grep "want $(cat hash)" trace
 '
 
 test_expect_success 'fetch lazy-fetches only to resolve deltas, protocol v2' '
@@ -538,12 +538,12 @@ test_expect_success 'fetch lazy-fetches only to resolve deltas, protocol v2' '
 		fetch "file://$(pwd)/server" main &&
 
 	# Verify that protocol version 2 was used.
-	grep "fetch< version 2" trace &&
+	test_grep "fetch< version 2" trace &&
 
 	# Verify the assumption that the client needed to fetch the delta base
 	# to resolve the delta.
 	git -C server rev-parse HEAD~1^{tree} >hash &&
-	grep "want $(cat hash)" trace
+	test_grep "want $(cat hash)" trace
 '
 
 test_expect_success 'fetch does not lazy-fetch missing targets of its refs' '
@@ -563,7 +563,7 @@ test_expect_success 'fetch does not lazy-fetch missing targets of its refs' '
 		--no-tags --recurse-submodules=no \
 		origin refs/tags/bar &&
 	FOO_HASH=$(git -C server rev-parse foo) &&
-	! grep "want $FOO_HASH" trace
+	test_grep ! "want $FOO_HASH" trace
 '
 
 # The following two tests must be in this order. It is important that
@@ -621,7 +621,7 @@ test_expect_success 'fetch from a partial clone, protocol v0' '
 	test_config -C client protocol.version 0 &&
 	test_commit -C client bar &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch "file://$(pwd)/server" &&
-	! grep "version 2" trace
+	test_grep ! "version 2" trace
 '
 
 test_expect_success 'fetch from a partial clone, protocol v2' '
@@ -640,7 +640,7 @@ test_expect_success 'fetch from a partial clone, protocol v2' '
 	test_config -C client protocol.version 2 &&
 	test_commit -C client bar &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch "file://$(pwd)/server" &&
-	grep "version 2" trace
+	test_grep "version 2" trace
 '
 
 test_expect_success 'repack does not loosen promisor objects' '
@@ -648,7 +648,7 @@ test_expect_success 'repack does not loosen promisor objects' '
 	git clone --bare --filter=blob:none "file://$(pwd)/srv.bare" client &&
 	test_when_finished "rm -rf client trace" &&
 	GIT_TRACE2_PERF="$(pwd)/trace" git -C client repack -A -d &&
-	grep "loosen_unused_packed_objects/loosened:0" trace
+	test_grep "loosen_unused_packed_objects/loosened:0" trace
 '
 
 test_expect_success 'lazy-fetch in submodule succeeds' '
@@ -824,7 +824,7 @@ test_expect_success 'when partial cloning, tolerate server not sending target of
 	# Exercise to make sure it works.
 	git -c protocol.version=2 clone \
 		--filter=blob:none $HTTPD_URL/one_time_script/server repo 2> err &&
-	! grep "missing object referenced by" err &&
+	test_grep ! "missing object referenced by" err &&
 
 	# Ensure that the one-time-script script was used.
 	! test -e "$HTTPD_ROOT_PATH/one-time-script"
@@ -881,13 +881,13 @@ test_expect_success PERL_TEST_HELPERS 'tolerate server sending REF_DELTA against
 	# by any 3 nybbles, then the OID of the delta base.
 	printf "f.,..%s" $(intersperse "," <deltabase_missing) >want &&
 	hex_unpack <thin.pack | intersperse "," >have &&
-	grep $(cat want) have &&
+	test_grep $(cat want) have &&
 
 	# Ensure that the pack contains one delta against HEAD^:have.txt,
 	# similar to the above.
 	printf "f.,..%s" $(intersperse "," <deltabase_have) >want &&
 	hex_unpack <thin.pack | intersperse "," >have &&
-	grep $(cat want) have &&
+	test_grep $(cat want) have &&
 
 	replace_packfile thin.pack &&
 
@@ -901,8 +901,8 @@ test_expect_success PERL_TEST_HELPERS 'tolerate server sending REF_DELTA against
 
 	# Ensure that the missing delta base was directly fetched, but not the
 	# one that the client has.
-	grep "want $(cat deltabase_missing)" trace &&
-	! grep "want $(cat deltabase_have)" trace &&
+	test_grep "want $(cat deltabase_missing)" trace &&
+	test_grep ! "want $(cat deltabase_have)" trace &&
 
 	# Ensure that the one-time-script script was used.
 	! test -e "$HTTPD_ROOT_PATH/one-time-script"
diff --git a/t/t5619-clone-local-ambiguous-transport.sh b/t/t5619-clone-local-ambiguous-transport.sh
index cce62bf78d..e4218e5c7f 100755
--- a/t/t5619-clone-local-ambiguous-transport.sh
+++ b/t/t5619-clone-local-ambiguous-transport.sh
@@ -64,7 +64,7 @@ test_expect_success 'ambiguous transport does not lead to arbitrary file-inclusi
 	#
 	# This works for now, and if we ever fix the URL detection, it
 	# is OK to change this to detect the transport error.
-	grep "protocol .* is not supported" err
+	test_grep "protocol .* is not supported" err
 '
 
 test_done
diff --git a/t/t5620-backfill.sh b/t/t5620-backfill.sh
index d2ea68e065..7462280470 100755
--- a/t/t5620-backfill.sh
+++ b/t/t5620-backfill.sh
@@ -144,7 +144,7 @@ test_expect_success 'do partial clone 2, backfill min batch size' '
 test_expect_success 'backfill --sparse without sparse-checkout fails' '
 	git init not-sparse &&
 	test_must_fail git -C not-sparse backfill --sparse 2>err &&
-	grep "problem loading sparse-checkout" err
+	test_grep "problem loading sparse-checkout" err
 '
 
 test_expect_success 'backfill --sparse' '
@@ -422,7 +422,7 @@ test_expect_success 'backfill range with include-edges enables fetch-free git-lo
 		-C backfill-log log -p HEAD~2..HEAD >log-output &&
 
 	# No promisor fetches should have been needed.
-	! grep "fetch_count" log-trace
+	test_grep ! "fetch_count" log-trace
 '
 
 test_expect_success 'backfill range without include edges causes on-demand fetches in git-log' '
@@ -439,7 +439,7 @@ test_expect_success 'backfill range without include edges causes on-demand fetch
 	GIT_TRACE2_EVENT="$(pwd)/log-no-bdy-trace" git \
 		-C backfill-log-no-bdy log -p HEAD~2..HEAD >log-output &&
 
-	grep "fetch_count" log-no-bdy-trace
+	test_grep "fetch_count" log-no-bdy-trace
 '
 
 test_expect_success 'backfill range enables fetch-free replay' '
@@ -470,7 +470,7 @@ test_expect_success 'backfill range enables fetch-free replay' '
 	GIT_TRACE2_EVENT="$(pwd)/replay-trace" git -C replay-dest.git \
 		replay --onto main topic~1..topic >replay-out &&
 
-	! grep "fetch_count" replay-trace
+	test_grep ! "fetch_count" replay-trace
 '
 
 test_expect_success 'backfill enables fetch-free merge' '
@@ -501,7 +501,7 @@ test_expect_success 'backfill enables fetch-free merge' '
 	GIT_TRACE2_EVENT="$(pwd)/merge-trace" git -C merge-dest \
 		merge origin/side -m "test merge" &&
 
-	! grep "fetch_count" merge-trace
+	test_grep ! "fetch_count" merge-trace
 '
 
 . "$TEST_DIRECTORY"/lib-httpd.sh
@@ -530,7 +530,7 @@ test_expect_success 'backfilling over HTTP succeeds' '
 	awk "{print \$1;}" <rev-list-out >oids &&
 	GIT_TRACE2_EVENT="$(pwd)/walk-trace" git -C backfill-http \
 		cat-file --batch-check <oids >batch-out &&
-	! grep missing batch-out
+	test_grep ! missing batch-out
 '
 
 # DO NOT add non-httpd-specific tests here, because the last part of this
diff --git a/t/t5700-protocol-v1.sh b/t/t5700-protocol-v1.sh
index a73b4d4ff6..ffeb01afae 100755
--- a/t/t5700-protocol-v1.sh
+++ b/t/t5700-protocol-v1.sh
@@ -33,9 +33,9 @@ test_expect_success 'clone with git:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v1
-	grep "clone> .*\\\0\\\0version=1\\\0$" log &&
+	test_grep "clone> .*\\\0\\\0version=1\\\0$" log &&
 	# Server responded using protocol v1
-	grep "clone< version 1" log
+	test_grep "clone< version 1" log
 '
 
 test_expect_success 'fetch with git:// using protocol v1' '
@@ -49,9 +49,9 @@ test_expect_success 'fetch with git:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v1
-	grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
+	test_grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
 	# Server responded using protocol v1
-	grep "fetch< version 1" log
+	test_grep "fetch< version 1" log
 '
 
 test_expect_success 'pull with git:// using protocol v1' '
@@ -63,9 +63,9 @@ test_expect_success 'pull with git:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v1
-	grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
+	test_grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
 	# Server responded using protocol v1
-	grep "fetch< version 1" log
+	test_grep "fetch< version 1" log
 '
 
 test_expect_success 'push with git:// using protocol v1' '
@@ -81,9 +81,9 @@ test_expect_success 'push with git:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v1
-	grep "push> .*\\\0\\\0version=1\\\0$" log &&
+	test_grep "push> .*\\\0\\\0version=1\\\0$" log &&
 	# Server responded using protocol v1
-	grep "push< version 1" log
+	test_grep "push< version 1" log
 '
 
 stop_git_daemon
@@ -104,7 +104,7 @@ test_expect_success 'clone with file:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "clone< version 1" log
+	test_grep "clone< version 1" log
 '
 
 test_expect_success 'fetch with file:// using protocol v1' '
@@ -118,7 +118,7 @@ test_expect_success 'fetch with file:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "fetch< version 1" log
+	test_grep "fetch< version 1" log
 '
 
 test_expect_success 'pull with file:// using protocol v1' '
@@ -130,7 +130,7 @@ test_expect_success 'pull with file:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "fetch< version 1" log
+	test_grep "fetch< version 1" log
 '
 
 test_expect_success 'push with file:// using protocol v1' '
@@ -146,7 +146,7 @@ test_expect_success 'push with file:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "push< version 1" log
+	test_grep "push< version 1" log
 '
 
 test_expect_success 'cloning branchless tagless but not refless remote' '
@@ -196,7 +196,7 @@ test_expect_success 'clone with ssh:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "clone< version 1" log
+	test_grep "clone< version 1" log
 '
 
 test_expect_success 'fetch with ssh:// using protocol v1' '
@@ -211,7 +211,7 @@ test_expect_success 'fetch with ssh:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "fetch< version 1" log
+	test_grep "fetch< version 1" log
 '
 
 test_expect_success 'pull with ssh:// using protocol v1' '
@@ -224,7 +224,7 @@ test_expect_success 'pull with ssh:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "fetch< version 1" log
+	test_grep "fetch< version 1" log
 '
 
 test_expect_success 'push with ssh:// using protocol v1' '
@@ -241,7 +241,7 @@ test_expect_success 'push with ssh:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "push< version 1" log
+	test_grep "push< version 1" log
 '
 
 test_expect_success 'clone propagates object-format from empty repo' '
@@ -277,9 +277,9 @@ test_expect_success 'clone with http:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v1
-	grep "Git-Protocol: version=1" log &&
+	test_grep "Git-Protocol: version=1" log &&
 	# Server responded using protocol v1
-	grep "git< version 1" log
+	test_grep "git< version 1" log
 '
 
 test_expect_success 'clone with http:// using protocol v1 with empty SHA-256 repo' '
@@ -291,9 +291,9 @@ test_expect_success 'clone with http:// using protocol v1 with empty SHA-256 rep
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v1
-	grep "Git-Protocol: version=1" log &&
+	test_grep "Git-Protocol: version=1" log &&
 	# Server responded using protocol v1
-	grep "git< version 1" log
+	test_grep "git< version 1" log
 '
 
 test_expect_success 'fetch with http:// using protocol v1' '
@@ -307,7 +307,7 @@ test_expect_success 'fetch with http:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "git< version 1" log
+	test_grep "git< version 1" log
 '
 
 test_expect_success 'pull with http:// using protocol v1' '
@@ -319,7 +319,7 @@ test_expect_success 'pull with http:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "git< version 1" log
+	test_grep "git< version 1" log
 '
 
 test_expect_success 'push with http:// using protocol v1' '
@@ -335,7 +335,7 @@ test_expect_success 'push with http:// using protocol v1' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v1
-	grep "git< version 1" log
+	test_grep "git< version 1" log
 '
 
 # DO NOT add non-httpd-specific tests here, because the last part of this
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
index d4c28bae39..108eb30945 100755
--- a/t/t5701-git-serve.sh
+++ b/t/t5701-git-serve.sh
@@ -97,7 +97,7 @@ test_expect_success 'request capability as command' '
 	0000
 	EOF
 	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
-	grep invalid.command.*agent err
+	test_grep invalid.command.*agent err
 '
 
 test_expect_success 'request command as capability' '
@@ -108,7 +108,7 @@ test_expect_success 'request command as capability' '
 	0000
 	EOF
 	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
-	grep unknown.capability err
+	test_grep unknown.capability err
 '
 
 test_expect_success 'requested command is command=value' '
@@ -118,7 +118,7 @@ test_expect_success 'requested command is command=value' '
 	0000
 	EOF
 	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
-	grep invalid.command.*ls-refs=whatever err
+	test_grep invalid.command.*ls-refs=whatever err
 '
 
 test_expect_success 'wrong object-format' '
@@ -175,7 +175,7 @@ test_expect_success 'ls-refs complains about unknown options' '
 	EOF
 
 	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
-	grep unexpected.line.*no-such-arg err
+	test_grep unexpected.line.*no-such-arg err
 '
 
 test_expect_success 'basic ref-prefixes' '
@@ -334,7 +334,7 @@ test_expect_success 'unexpected lines are not allowed in fetch request' '
 		cd server &&
 		test_must_fail test-tool serve-v2 --stateless-rpc
 	) <in >/dev/null 2>err &&
-	grep "unexpected line: .this-is-not-a-command." err
+	test_grep "unexpected line: .this-is-not-a-command." err
 '
 
 # Test the basics of object-info
@@ -410,7 +410,7 @@ test_expect_success 'object-info missing from capabilities when disabled' '
 		--advertise-capabilities >out &&
 	test-tool pkt-line unpack <out >actual &&
 
-	! grep object.info actual
+	test_grep ! object.info actual
 '
 
 test_expect_success 'object-info commands rejected when disabled' '
@@ -421,7 +421,7 @@ test_expect_success 'object-info commands rejected when disabled' '
 	EOF
 
 	test_must_fail test-tool serve-v2 --stateless-rpc <in 2>err &&
-	grep invalid.command err
+	test_grep invalid.command err
 '
 
 test_done
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index 9f6cf4142d..46f24dc0a3 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -27,9 +27,9 @@ test_expect_success 'list refs with git:// using protocol v2' '
 		ls-remote --symref "$GIT_DAEMON_URL/parent" >actual &&
 
 	# Client requested to use protocol v2
-	grep "ls-remote> .*\\\0\\\0version=2\\\0$" log &&
+	test_grep "ls-remote> .*\\\0\\\0version=2\\\0$" log &&
 	# Server responded using protocol v2
-	grep "ls-remote< version 2" log &&
+	test_grep "ls-remote< version 2" log &&
 
 	git ls-remote --symref "$GIT_DAEMON_URL/parent" >expect &&
 	test_cmp expect actual
@@ -59,9 +59,9 @@ test_expect_success 'clone with git:// using protocol v2' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v2
-	grep "clone> .*\\\0\\\0version=2\\\0$" log &&
+	test_grep "clone> .*\\\0\\\0version=2\\\0$" log &&
 	# Server responded using protocol v2
-	grep "clone< version 2" log
+	test_grep "clone< version 2" log
 '
 
 test_expect_success 'fetch with git:// using protocol v2' '
@@ -77,9 +77,9 @@ test_expect_success 'fetch with git:// using protocol v2' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v2
-	grep "fetch> .*\\\0\\\0version=2\\\0$" log &&
+	test_grep "fetch> .*\\\0\\\0version=2\\\0$" log &&
 	# Server responded using protocol v2
-	grep "fetch< version 2" log
+	test_grep "fetch< version 2" log
 '
 
 test_expect_success 'fetch by hash without tag following with protocol v2 does not list refs' '
@@ -91,8 +91,8 @@ test_expect_success 'fetch by hash without tag following with protocol v2 does n
 	GIT_TRACE_PACKET="$(pwd)/log" git -C daemon_child -c protocol.version=2 \
 		fetch --no-tags origin $(cat two_a_hash) &&
 
-	grep "fetch< version 2" log &&
-	! grep "fetch> command=ls-refs" log
+	test_grep "fetch< version 2" log &&
+	test_grep ! "fetch> command=ls-refs" log
 '
 
 test_expect_success 'pull with git:// using protocol v2' '
@@ -106,9 +106,9 @@ test_expect_success 'pull with git:// using protocol v2' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v2
-	grep "fetch> .*\\\0\\\0version=2\\\0$" log &&
+	test_grep "fetch> .*\\\0\\\0version=2\\\0$" log &&
 	# Server responded using protocol v2
-	grep "fetch< version 2" log
+	test_grep "fetch< version 2" log
 '
 
 test_expect_success 'push with git:// and a config of v2 does not request v2' '
@@ -130,9 +130,9 @@ test_expect_success 'push with git:// and a config of v2 does not request v2' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v2
-	! grep "push> .*\\\0\\\0version=2\\\0$" log &&
+	test_grep ! "push> .*\\\0\\\0version=2\\\0$" log &&
 	# Server responded using protocol v2
-	! grep "push< version 2" log
+	test_grep ! "push< version 2" log
 '
 
 stop_git_daemon
@@ -151,7 +151,7 @@ test_expect_success 'list refs with file:// using protocol v2' '
 		ls-remote --symref "file://$(pwd)/file_parent" >actual &&
 
 	# Server responded using protocol v2
-	grep "ls-remote< version 2" log &&
+	test_grep "ls-remote< version 2" log &&
 
 	git ls-remote --symref "file://$(pwd)/file_parent" >expect &&
 	test_cmp expect actual
@@ -181,8 +181,8 @@ test_expect_success 'server-options are sent when using ls-remote' '
 	EOF
 
 	test_cmp expect actual &&
-	grep "server-option=hello" log &&
-	grep "server-option=world" log
+	test_grep "server-option=hello" log &&
+	test_grep "server-option=world" log
 '
 
 test_expect_success 'server-options from configuration are used by ls-remote' '
@@ -241,12 +241,12 @@ test_expect_success 'clone with file:// using protocol v2' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v2
-	grep "clone< version 2" log &&
+	test_grep "clone< version 2" log &&
 
 	# Client sent ref-prefixes to filter the ref-advertisement
-	grep "ref-prefix HEAD" log &&
-	grep "ref-prefix refs/heads/" log &&
-	grep "ref-prefix refs/tags/" log
+	test_grep "ref-prefix HEAD" log &&
+	test_grep "ref-prefix refs/heads/" log &&
+	test_grep "ref-prefix refs/tags/" log
 '
 
 test_expect_success 'clone of empty repo propagates name of default branch' '
@@ -311,7 +311,7 @@ test_expect_success 'clone propagates unborn HEAD from non-empty repo' '
 	echo "refs/heads/mydefaultbranch" >expect &&
 	git -C file_unborn_child symbolic-ref HEAD >actual &&
 	test_cmp expect actual &&
-	grep "warning: remote HEAD refers to nonexistent ref" stderr
+	test_grep "warning: remote HEAD refers to nonexistent ref" stderr
 '
 
 test_expect_success 'clone propagates object-format from empty repo' '
@@ -343,7 +343,7 @@ test_expect_success 'bare clone propagates unborn HEAD from non-empty repo' '
 	echo "refs/heads/mydefaultbranch" >expect &&
 	git -C file_unborn_child.git symbolic-ref HEAD >actual &&
 	test_cmp expect actual &&
-	! grep "warning:" stderr
+	test_grep ! "warning:" stderr
 '
 
 test_expect_success 'defaulted HEAD uses remote branch if available' '
@@ -366,7 +366,7 @@ test_expect_success 'defaulted HEAD uses remote branch if available' '
 	git -C file_unborn_child symbolic-ref HEAD >actual &&
 	test_cmp expect actual &&
 	test_path_is_file file_unborn_child/stuff.t &&
-	! grep "warning:" stderr
+	test_grep ! "warning:" stderr
 '
 
 test_expect_success 'fetch with file:// using protocol v2' '
@@ -382,7 +382,7 @@ test_expect_success 'fetch with file:// using protocol v2' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v2
-	grep "fetch< version 2" log
+	test_grep "fetch< version 2" log
 '
 
 test_expect_success 'ref advertisement is filtered during fetch using protocol v2' '
@@ -398,8 +398,8 @@ test_expect_success 'ref advertisement is filtered during fetch using protocol v
 	git -C file_parent log -1 --format=%s >expect &&
 	test_cmp expect actual &&
 
-	grep "refs/heads/main" log &&
-	! grep "refs/heads/unwanted-branch" log
+	test_grep "refs/heads/main" log &&
+	test_grep ! "refs/heads/unwanted-branch" log
 '
 
 test_expect_success 'server-options are sent when fetching' '
@@ -414,8 +414,8 @@ test_expect_success 'server-options are sent when fetching' '
 	git -C file_parent log -1 --format=%s >expect &&
 	test_cmp expect actual &&
 
-	grep "server-option=hello" log &&
-	grep "server-option=world" log
+	test_grep "server-option=hello" log &&
+	test_grep "server-option=world" log
 '
 
 test_expect_success 'server-options are sent when fetch multiple remotes' '
@@ -485,8 +485,8 @@ test_expect_success 'server-options are sent when cloning' '
 		clone --server-option=hello --server-option=world \
 		"file://$(pwd)/file_parent" myclone &&
 
-	grep "server-option=hello" log &&
-	grep "server-option=world" log
+	test_grep "server-option=hello" log &&
+	test_grep "server-option=world" log
 '
 
 test_expect_success 'server-options from configuration are used by git-clone' '
@@ -578,12 +578,12 @@ test_expect_success 'setup filter tests' '
 test_expect_success 'partial clone' '
 	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
 		clone --filter=blob:none "file://$(pwd)/server" client &&
-	grep "version 2" trace &&
+	test_grep "version 2" trace &&
 
 	# Ensure that the old version of the file is missing
 	git -C client rev-list --quiet --objects --missing=print main \
 		>observed.oids &&
-	grep "$(git -C server rev-parse message1:a.txt)" observed.oids &&
+	test_grep "$(git -C server rev-parse message1:a.txt)" observed.oids &&
 
 	# Ensure that client passes fsck
 	git -C client fsck
@@ -593,11 +593,11 @@ test_expect_success 'dynamically fetch missing object' '
 	rm "$(pwd)/trace" &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		cat-file -p $(git -C server rev-parse message1:a.txt) &&
-	grep "version 2" trace
+	test_grep "version 2" trace
 '
 
 test_expect_success 'when dynamically fetching missing object, do not list refs' '
-	! grep "git> command=ls-refs" trace
+	test_grep ! "git> command=ls-refs" trace
 '
 
 test_expect_success 'partial fetch' '
@@ -607,12 +607,12 @@ test_expect_success 'partial fetch' '
 
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		fetch --filter=blob:none "$SERVER" main:refs/heads/other &&
-	grep "version 2" trace &&
+	test_grep "version 2" trace &&
 
 	# Ensure that the old version of the file is missing
 	git -C client rev-list --quiet --objects --missing=print other \
 		>observed.oids &&
-	grep "$(git -C server rev-parse message1:a.txt)" observed.oids &&
+	test_grep "$(git -C server rev-parse message1:a.txt)" observed.oids &&
 
 	# Ensure that client passes fsck
 	git -C client fsck
@@ -625,14 +625,14 @@ test_expect_success 'do not advertise filter if not configured to do so' '
 	git -C server config uploadpack.allowfilter 1 &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
 		ls-remote "$SERVER" &&
-	grep "fetch=.*filter" trace &&
+	test_grep "fetch=.*filter" trace &&
 
 	rm "$(pwd)/trace" &&
 	git -C server config uploadpack.allowfilter 0 &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
 		ls-remote "$SERVER" &&
 	grep "fetch=" trace >fetch_capabilities &&
-	! grep filter fetch_capabilities
+	test_grep ! filter fetch_capabilities
 '
 
 test_expect_success 'partial clone warns if filter is not advertised' '
@@ -658,7 +658,7 @@ test_expect_success 'even with handcrafted request, filter does not work if not
 
 	test_must_fail test-tool -C server serve-v2 --stateless-rpc \
 		<in >/dev/null 2>err &&
-	grep "unexpected line: .filter blob:none." err &&
+	test_grep "unexpected line: .filter blob:none." err &&
 
 	# Exercise to ensure that if advertised, filter works
 	git -C server config uploadpack.allowfilter 1 &&
@@ -675,8 +675,8 @@ test_expect_success 'default refspec is used to filter ref when fetching' '
 	git -C file_parent log -1 --format=%s three >expect &&
 	test_cmp expect actual &&
 
-	grep "ref-prefix refs/heads/" log &&
-	grep "ref-prefix refs/tags/" log
+	test_grep "ref-prefix refs/heads/" log &&
+	test_grep "ref-prefix refs/tags/" log
 '
 
 test_expect_success 'set up parent for prefix tests' '
@@ -750,9 +750,9 @@ test_expect_success 'fetch supports various ways of have lines' '
 		"$(git -C server rev-parse fetch-by-sha1)" &&
 
 	# Ensure that the appropriate prefixes are sent (using a sample)
-	grep "fetch> ref-prefix dwim" trace &&
-	grep "fetch> ref-prefix refs/heads/dwim" trace &&
-	grep "fetch> ref-prefix refs/tags/prefix" trace &&
+	test_grep "fetch> ref-prefix dwim" trace &&
+	test_grep "fetch> ref-prefix refs/heads/dwim" trace &&
+	test_grep "fetch> ref-prefix refs/tags/prefix" trace &&
 
 	# Ensure that the correct objects are returned
 	git -C client cat-file -e $(git -C server rev-parse dwim) &&
@@ -779,9 +779,9 @@ test_expect_success 'fetch supports include-tag and tag following' '
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		fetch "$(pwd)/server" to_fetch:to_fetch &&
 
-	grep "fetch> ref-prefix to_fetch" trace &&
-	grep "fetch> ref-prefix refs/tags/" trace &&
-	grep "fetch> include-tag" trace &&
+	test_grep "fetch> ref-prefix to_fetch" trace &&
+	test_grep "fetch> ref-prefix refs/tags/" trace &&
+	test_grep "fetch> include-tag" trace &&
 
 	git -C client cat-file -e $(git -C client rev-parse annotated_tag)
 '
@@ -805,7 +805,7 @@ test_expect_success 'upload-pack respects client shallows' '
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		fetch origin newbranch &&
 	# Ensure that protocol v2 is used
-	grep "fetch< version 2" trace
+	test_grep "fetch< version 2" trace
 '
 
 test_expect_success 'ensure that multiple fetches in same process from a shallow repo works' '
@@ -823,7 +823,7 @@ test_expect_success 'ensure that multiple fetches in same process from a shallow
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		fetch --shallow-exclude one origin &&
 	# Ensure that protocol v2 is used
-	grep "fetch< version 2" trace
+	test_grep "fetch< version 2" trace
 '
 
 test_expect_success 'deepen-relative' '
@@ -844,7 +844,7 @@ test_expect_success 'deepen-relative' '
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		fetch --deepen=1 origin &&
 	# Ensure that protocol v2 is used
-	grep "fetch< version 2" trace &&
+	test_grep "fetch< version 2" trace &&
 
 	git -C client log --pretty=tformat:%s origin/main >actual &&
 	cat >expected <<-\EOF &&
@@ -909,7 +909,7 @@ test_expect_success 'file:// --negotiate-only' '
 		--negotiation-tip=$(git -C client rev-parse HEAD) \
 		origin >out &&
 	COMMON=$(git -C "$SERVER" rev-parse two) &&
-	grep "$COMMON" out
+	test_grep "$COMMON" out
 '
 
 test_expect_success 'file:// --negotiate-only with protocol v0' '
@@ -932,7 +932,7 @@ test_expect_success 'push with custom path does not request v2' '
 		--receive-pack="env >../env.trace; git-receive-pack" \
 		origin HEAD:refs/heads/custom-push-test &&
 	test_path_is_file env.trace &&
-	! grep ^GIT_PROTOCOL env.trace
+	test_grep ! ^GIT_PROTOCOL env.trace
 '
 
 test_expect_success 'fetch with custom path does request v2' '
@@ -940,7 +940,7 @@ test_expect_success 'fetch with custom path does request v2' '
 	git -C client fetch \
 		--upload-pack="env >../env.trace; git-upload-pack" \
 		origin HEAD &&
-	grep ^GIT_PROTOCOL=version=2 env.trace
+	test_grep ^GIT_PROTOCOL=version=2 env.trace
 '
 
 test_expect_success 'archive with custom path does not request v2' '
@@ -950,7 +950,7 @@ test_expect_success 'archive with custom path does not request v2' '
 		--remote=origin \
 		HEAD >/dev/null &&
 	test_path_is_file env.trace &&
-	! grep ^GIT_PROTOCOL env.trace
+	test_grep ! ^GIT_PROTOCOL env.trace
 '
 
 test_expect_success 'reject client packfile-uris if not advertised' '
@@ -994,11 +994,11 @@ test_expect_success 'clone with http:// using protocol v2' '
 	test_cmp expect actual &&
 
 	# Client requested to use protocol v2
-	grep "Git-Protocol: version=2" log &&
+	test_grep "Git-Protocol: version=2" log &&
 	# Server responded using protocol v2
-	grep "git< version 2" log &&
+	test_grep "git< version 2" log &&
 	# Verify that the chunked encoding sending codepath is NOT exercised
-	! grep "Send header: Transfer-Encoding: chunked" log
+	test_grep ! "Send header: Transfer-Encoding: chunked" log
 '
 
 test_expect_success 'clone repository with http:// using protocol v2 with incomplete pktline length' '
@@ -1011,9 +1011,9 @@ test_expect_success 'clone repository with http:// using protocol v2 with incomp
 		clone "$HTTPD_URL/smart/incomplete_length" incomplete_length_child 2>err &&
 
 	# Client requested to use protocol v2
-	grep "Git-Protocol: version=2" log &&
+	test_grep "Git-Protocol: version=2" log &&
 	# Server responded using protocol v2
-	grep "git< version 2" log &&
+	test_grep "git< version 2" log &&
 	# Client reported appropriate failure
 	test_grep "bytes of length header were received" err
 '
@@ -1028,9 +1028,9 @@ test_expect_success 'clone repository with http:// using protocol v2 with incomp
 		clone "$HTTPD_URL/smart/incomplete_body" incomplete_body_child 2>err &&
 
 	# Client requested to use protocol v2
-	grep "Git-Protocol: version=2" log &&
+	test_grep "Git-Protocol: version=2" log &&
 	# Server responded using protocol v2
-	grep "git< version 2" log &&
+	test_grep "git< version 2" log &&
 	# Client reported appropriate failure
 	test_grep "bytes of body are still expected" err
 '
@@ -1043,9 +1043,9 @@ test_expect_success 'clone with http:// using protocol v2 and invalid parameters
 		clone --shallow-since=20151012 "$HTTPD_URL/smart/http_parent" http_child_invalid &&
 
 	# Client requested to use protocol v2
-	grep "Git-Protocol: version=2" log &&
+	test_grep "Git-Protocol: version=2" log &&
 	# Server responded using protocol v2
-	grep "git< version 2" log
+	test_grep "git< version 2" log
 '
 
 test_expect_success 'clone big repository with http:// using protocol v2' '
@@ -1070,11 +1070,11 @@ test_expect_success 'clone big repository with http:// using protocol v2' '
 		clone "$HTTPD_URL/smart/big" big_child &&
 
 	# Client requested to use protocol v2
-	grep "Git-Protocol: version=2" log &&
+	test_grep "Git-Protocol: version=2" log &&
 	# Server responded using protocol v2
-	grep "git< version 2" log &&
+	test_grep "git< version 2" log &&
 	# Verify that the chunked encoding sending codepath is exercised
-	grep "Send header: Transfer-Encoding: chunked" log
+	test_grep "Send header: Transfer-Encoding: chunked" log
 '
 
 test_expect_success 'fetch with http:// using protocol v2' '
@@ -1090,7 +1090,7 @@ test_expect_success 'fetch with http:// using protocol v2' '
 	test_cmp expect actual &&
 
 	# Server responded using protocol v2
-	grep "git< version 2" log
+	test_grep "git< version 2" log
 '
 
 test_expect_success 'fetch with http:// by hash without tag following with protocol v2 does not list refs' '
@@ -1102,8 +1102,8 @@ test_expect_success 'fetch with http:// by hash without tag following with proto
 	GIT_TRACE_PACKET="$(pwd)/log" git -C http_child -c protocol.version=2 \
 		fetch --no-tags origin $(cat two_a_hash) &&
 
-	grep "fetch< version 2" log &&
-	! grep "fetch> command=ls-refs" log
+	test_grep "fetch< version 2" log &&
+	test_grep ! "fetch> command=ls-refs" log
 '
 
 test_expect_success 'fetch from namespaced repo respects namespaces' '
@@ -1120,7 +1120,7 @@ test_expect_success 'fetch from namespaced repo respects namespaces' '
 		refs/heads/main:refs/heads/theirs &&
 
 	# Server responded using protocol v2
-	grep "fetch< version 2" log &&
+	test_grep "fetch< version 2" log &&
 
 	git -C "$HTTPD_DOCUMENT_ROOT_PATH/nsrepo" rev-parse one >expect &&
 	git -C http_child rev-parse theirs >actual &&
@@ -1157,9 +1157,9 @@ test_expect_success 'push with http:// and a config of v2 does not request v2' '
 	test_cmp expect actual &&
 
 	# Client did not request to use protocol v2
-	! grep "Git-Protocol: version=2" log &&
+	test_grep ! "Git-Protocol: version=2" log &&
 	# Server did not respond using protocol v2
-	! grep "git< version 2" log
+	test_grep ! "git< version 2" log
 '
 
 test_expect_success 'when server sends "ready", expect DELIM' '
@@ -1207,8 +1207,8 @@ test_expect_success 'when server does not send "ready", expect FLUSH' '
 	test_must_fail env GIT_TRACE_PACKET="$(pwd)/log" git -C http_child \
 		-c protocol.version=2 \
 		fetch "$HTTPD_URL/one_time_script/http_parent" 2> err &&
-	grep "fetch< .*acknowledgments" log &&
-	! grep "fetch< .*ready" log &&
+	test_grep "fetch< .*acknowledgments" log &&
+	test_grep ! "fetch< .*ready" log &&
 	test_grep "expected no other sections to be sent after no .ready." err
 '
 
@@ -1446,7 +1446,7 @@ test_expect_success 'packfile-uri path redacted in trace' '
 		-c fetch.uriprotocols=http,https \
 		clone "$HTTPD_URL/smart/http_parent" http_child &&
 
-	grep -F "clone< \\1$(cat packh) $HTTPD_URL/<redacted>" log
+	test_grep -F "clone< \\1$(cat packh) $HTTPD_URL/<redacted>" log
 '
 
 test_expect_success 'packfile-uri path not redacted in trace when GIT_TRACE_REDACT=0' '
@@ -1472,7 +1472,7 @@ test_expect_success 'packfile-uri path not redacted in trace when GIT_TRACE_REDA
 		-c fetch.uriprotocols=http,https \
 		clone "$HTTPD_URL/smart/http_parent" http_child &&
 
-	grep -F "clone< \\1$(cat packh) $HTTPD_URL/dumb/mypack-$(cat packh).pack" log
+	test_grep -F "clone< \\1$(cat packh) $HTTPD_URL/dumb/mypack-$(cat packh).pack" log
 '
 
 test_expect_success 'http:// --negotiate-only' '
@@ -1487,7 +1487,7 @@ test_expect_success 'http:// --negotiate-only' '
 		--negotiation-tip=$(git -C client rev-parse HEAD) \
 		origin >out &&
 	COMMON=$(git -C "$SERVER" rev-parse two) &&
-	grep "$COMMON" out
+	test_grep "$COMMON" out
 '
 
 test_expect_success 'http:// --negotiate-only without wait-for-done support' '
diff --git a/t/t5703-upload-pack-ref-in-want.sh b/t/t5703-upload-pack-ref-in-want.sh
index 249137b467..330d049b2c 100755
--- a/t/t5703-upload-pack-ref-in-want.sh
+++ b/t/t5703-upload-pack-ref-in-want.sh
@@ -101,7 +101,7 @@ test_expect_success 'invalid want-ref line' '
 
 	test-tool pkt-line pack <pkt >in &&
 	test_must_fail test-tool serve-v2 --stateless-rpc 2>out <in &&
-	grep "unknown ref" out
+	test_grep "unknown ref" out
 '
 
 test_expect_success 'basic want-ref' '
@@ -235,11 +235,11 @@ test_expect_success 'fetching with exact OID' '
 		git -C local fetch origin \
 		"$oid":refs/heads/actual &&
 
-	grep \"key\":\"total_rounds\",\"value\":\"2\" trace2 &&
+	test_grep \"key\":\"total_rounds\",\"value\":\"2\" trace2 &&
 	git -C "$REPO" rev-parse "d" >expected &&
 	git -C local rev-parse refs/heads/actual >actual &&
 	test_cmp expected actual &&
-	grep "want $oid" log
+	test_grep "want $oid" log
 '
 
 test_expect_success 'fetching multiple refs' '
@@ -252,8 +252,8 @@ test_expect_success 'fetching multiple refs' '
 	git -C "$REPO" rev-parse "main" "baz" >expected &&
 	git -C local rev-parse refs/remotes/origin/main refs/remotes/origin/baz >actual &&
 	test_cmp expected actual &&
-	grep "want-ref refs/heads/main" log &&
-	grep "want-ref refs/heads/baz" log
+	test_grep "want-ref refs/heads/main" log &&
+	test_grep "want-ref refs/heads/baz" log
 '
 
 test_expect_success 'fetching ref and exact OID' '
@@ -268,8 +268,8 @@ test_expect_success 'fetching ref and exact OID' '
 	git -C "$REPO" rev-parse "main" "b" >expected &&
 	git -C local rev-parse refs/remotes/origin/main refs/heads/actual >actual &&
 	test_cmp expected actual &&
-	grep "want $oid" log &&
-	grep "want-ref refs/heads/main" log
+	test_grep "want $oid" log &&
+	test_grep "want-ref refs/heads/main" log
 '
 
 test_expect_success 'fetching with wildcard that does not match any refs' '
@@ -291,8 +291,8 @@ test_expect_success 'fetching with wildcard that matches multiple refs' '
 	git -C "$REPO" rev-parse "o/foo" "o/bar" >expected &&
 	git -C local rev-parse "o/foo" "o/bar" >actual &&
 	test_cmp expected actual &&
-	grep "want-ref refs/heads/o/foo" log &&
-	grep "want-ref refs/heads/o/bar" log
+	test_grep "want-ref refs/heads/o/foo" log &&
+	test_grep "want-ref refs/heads/o/bar" log
 '
 
 REPO="$(pwd)/repo-ns"
@@ -345,7 +345,7 @@ test_expect_success 'with namespace: want-ref outside namespace is unknown' '
 
 	test_must_fail env GIT_NAMESPACE=ns \
 		test-tool -C "$REPO" serve-v2 --stateless-rpc >out <in &&
-	grep "unknown ref" out
+	test_grep "unknown ref" out
 '
 
 # Cross-check refs/heads/ns-no indeed exists
@@ -381,7 +381,7 @@ test_expect_success 'with namespace: hideRefs is matched, relative to namespace'
 
 	test_must_fail env GIT_NAMESPACE=ns \
 		test-tool -C "$REPO" serve-v2 --stateless-rpc >out <in &&
-	grep "unknown ref" out
+	test_grep "unknown ref" out
 '
 
 # Cross-check refs/heads/hidden indeed exists
diff --git a/t/t5705-session-id-in-capabilities.sh b/t/t5705-session-id-in-capabilities.sh
index ed38c76c29..ef0db57d1f 100755
--- a/t/t5705-session-id-in-capabilities.sh
+++ b/t/t5705-session-id-in-capabilities.sh
@@ -55,8 +55,8 @@ do
 		git -c protocol.version=$PROTO -C local fetch \
 			--upload-pack "GIT_TRACE2_EVENT=\"$(pwd)/tr2-server-events\" git-upload-pack" \
 			origin &&
-		grep \"key\":\"server-sid\" tr2-client-events &&
-		grep \"key\":\"client-sid\" tr2-server-events
+		test_grep \"key\":\"server-sid\" tr2-client-events &&
+		test_grep \"key\":\"client-sid\" tr2-server-events
 	'
 
 	test_expect_success "session IDs advertised (push v${PROTO})" '
@@ -68,8 +68,8 @@ do
 		git -c protocol.version=$PROTO -C local push \
 			--receive-pack "GIT_TRACE2_EVENT=\"$(pwd)/tr2-server-events\" git-receive-pack" \
 			origin HEAD:new-branch &&
-		grep \"key\":\"server-sid\" tr2-client-events &&
-		grep \"key\":\"client-sid\" tr2-server-events
+		test_grep \"key\":\"server-sid\" tr2-client-events &&
+		test_grep \"key\":\"client-sid\" tr2-server-events
 	'
 
 	test_expect_success "client & server log negotiated version (v${PROTO})" '
@@ -79,8 +79,8 @@ do
 		git -c protocol.version=$PROTO -C local fetch \
 			--upload-pack "GIT_TRACE2_EVENT=\"$(pwd)/tr2-server-events\" git-upload-pack" \
 			origin &&
-		grep \"key\":\"negotiated-version\",\"value\":\"$PROTO\" tr2-client-events &&
-		grep \"key\":\"negotiated-version\",\"value\":\"$PROTO\" tr2-server-events
+		test_grep \"key\":\"negotiated-version\",\"value\":\"$PROTO\" tr2-client-events &&
+		test_grep \"key\":\"negotiated-version\",\"value\":\"$PROTO\" tr2-server-events
 	'
 done
 
diff --git a/t/t5750-bundle-uri-parse.sh b/t/t5750-bundle-uri-parse.sh
index 294f9d9c64..70ae94c4d0 100755
--- a/t/t5750-bundle-uri-parse.sh
+++ b/t/t5750-bundle-uri-parse.sh
@@ -78,7 +78,7 @@ test_expect_success 'bundle_uri_parse_line(): relative URIs and parent paths' '
 	# now until the interface for relative_url() allows for reporting
 	# an error instead of die()ing.
 	test_must_fail test-tool bundle-uri parse-key-values in >actual 2>err &&
-	grep "fatal: cannot strip one component off url" err
+	test_grep "fatal: cannot strip one component off url" err
 '
 
 test_expect_success 'bundle_uri_parse_line() parsing edge cases: empty key or value' '
@@ -283,7 +283,7 @@ test_expect_success 'parse config format edge cases: creationToken heuristic' '
 	EOF
 
 	test-tool bundle-uri parse-config expect >actual 2>err &&
-	grep "could not parse bundle list key creationToken with value '\''bogus'\''" err
+	test_grep "could not parse bundle list key creationToken with value '\''bogus'\''" err
 '
 
 test_expect_success 'parse config format: bundle with missing uri' '
@@ -296,7 +296,7 @@ test_expect_success 'parse config format: bundle with missing uri' '
 	EOF
 
 	test_must_fail test-tool bundle-uri parse-config input 2>err &&
-	grep "bundle '\''missing-uri'\'' has no uri" err
+	test_grep "bundle '\''missing-uri'\'' has no uri" err
 '
 
 test_expect_success 'parse config format: bundle with url instead of uri' '
@@ -309,7 +309,7 @@ test_expect_success 'parse config format: bundle with url instead of uri' '
 	EOF
 
 	test_must_fail test-tool bundle-uri parse-config input 2>err &&
-	grep "bundle '\''typo'\'' has no uri" err
+	test_grep "bundle '\''typo'\'' has no uri" err
 '
 
 test_done
diff --git a/t/t5801-remote-helpers.sh b/t/t5801-remote-helpers.sh
index d21877150e..5fafc857b8 100755
--- a/t/t5801-remote-helpers.sh
+++ b/t/t5801-remote-helpers.sh
@@ -306,7 +306,7 @@ test_expect_success 'push messages' '
 	echo new >>file &&
 	git commit -a -m new &&
 	git push origin new_branch 2> msg &&
-	! grep "\[new branch\]" msg
+	test_grep ! "\[new branch\]" msg
 	)
 '
 
@@ -352,7 +352,7 @@ test_expect_success 'totally broken helper reports failure message' '
 	test_must_fail \
 		env PATH="$PWD:$PATH" \
 		git clone broken://example.com/foo.git 2>stderr &&
-	grep aborted stderr
+	test_grep aborted stderr
 '
 
 test_done
diff --git a/t/t5810-proto-disable-local.sh b/t/t5810-proto-disable-local.sh
index 96a2c46e7a..cb3b13f8d3 100755
--- a/t/t5810-proto-disable-local.sh
+++ b/t/t5810-proto-disable-local.sh
@@ -28,7 +28,7 @@ test_expect_success 'setup repo with dash' '
 test_expect_success 'repo names starting with dash are rejected' '
 	rm -f trace.out &&
 	test_must_fail env GIT_TRACE="$PWD/trace.out" git fetch -- -repo.git &&
-	! grep upload-pack trace.out
+	test_grep ! upload-pack trace.out
 '
 
 test_expect_success 'full paths still work' '
diff --git a/t/t5813-proto-disable-ssh.sh b/t/t5813-proto-disable-ssh.sh
index 045e2fe6ce..1800d27f89 100755
--- a/t/t5813-proto-disable-ssh.sh
+++ b/t/t5813-proto-disable-ssh.sh
@@ -24,7 +24,7 @@ test_proto "git+ssh://" ssh "git+ssh://remote$PWD/remote/repo.git"
 # simply confirm from its output that it did not run at all.
 test_expect_success 'hostnames starting with dash are rejected' '
 	test_must_fail git clone ssh://-remote/repo.git dash-host 2>stderr &&
-	! grep ^ssh: stderr
+	test_grep ! ^ssh: stderr
 '
 
 test_expect_success 'setup repo with dash' '
@@ -34,7 +34,7 @@ test_expect_success 'setup repo with dash' '
 
 test_expect_success 'repo names starting with dash are rejected' '
 	test_must_fail git clone remote:-repo.git dash-path 2>stderr &&
-	! grep ^ssh: stderr
+	test_grep ! ^ssh: stderr
 '
 
 test_expect_success 'full paths still work' '
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index a95ba576fa..ce968f685e 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -17,8 +17,8 @@ test_expect_success setup '
 
 test_expect_success 'rev-list --objects heeds pathspecs' '
 	git rev-list --objects HEAD -- wanted_file >output &&
-	grep wanted_file output &&
-	! grep unwanted_file output
+	test_grep wanted_file output &&
+	test_grep ! unwanted_file output
 '
 
 test_expect_success 'rev-list --objects with pathspecs and deeper paths' '
@@ -29,11 +29,11 @@ test_expect_success 'rev-list --objects with pathspecs and deeper paths' '
 	git commit -m two &&
 
 	git rev-list --objects HEAD -- foo >output &&
-	grep foo/file output &&
+	test_grep foo/file output &&
 
 	git rev-list --objects HEAD -- foo/file >output &&
-	grep foo/file output &&
-	! grep unwanted_file output
+	test_grep foo/file output &&
+	test_grep ! unwanted_file output
 '
 
 test_expect_success 'rev-list --objects with pathspecs and copied files' '
@@ -49,28 +49,28 @@ test_expect_success 'rev-list --objects with pathspecs and copied files' '
 
 	ONE=$(git rev-parse HEAD:one) &&
 	git rev-list --objects HEAD two >output &&
-	grep "$ONE two/three" output &&
-	! grep one output
+	test_grep "$ONE two/three" output &&
+	test_grep ! one output
 '
 
 test_expect_success 'rev-list --objects --no-object-names has no space/names' '
 	git rev-list --objects --no-object-names HEAD >output &&
-	! grep wanted_file output &&
-	! grep unwanted_file output &&
-	! grep " " output
+	test_grep ! wanted_file output &&
+	test_grep ! unwanted_file output &&
+	test_grep ! " " output
 '
 
 test_expect_success 'rev-list --objects --no-object-names works with cat-file' '
 	git rev-list --objects --no-object-names --all >list-output &&
 	git cat-file --batch-check <list-output >cat-output &&
-	! grep missing cat-output
+	test_grep ! missing cat-output
 '
 
 test_expect_success '--no-object-names and --object-names are last-one-wins' '
 	git rev-list --objects --no-object-names --object-names --all >output &&
-	grep wanted_file output &&
+	test_grep wanted_file output &&
 	git rev-list --objects --object-names --no-object-names --all >output &&
-	! grep wanted_file output
+	test_grep ! wanted_file output
 '
 
 test_expect_success 'rev-list A..B and rev-list ^A B are the same' '
diff --git a/t/t6005-rev-list-count.sh b/t/t6005-rev-list-count.sh
index 6cde997e13..0bef5838df 100755
--- a/t/t6005-rev-list-count.sh
+++ b/t/t6005-rev-list-count.sh
@@ -18,7 +18,7 @@ test_expect_success 'no options' '
 
 test_expect_success '--max-count' '
 	test_must_fail git rev-list --max-count=1q HEAD 2>error &&
-	grep "not an integer" error &&
+	test_grep "not an integer" error &&
 
 	test_stdout_line_count = 0 git rev-list HEAD --max-count=0 &&
 	test_stdout_line_count = 3 git rev-list HEAD --max-count=3 &&
@@ -29,10 +29,10 @@ test_expect_success '--max-count' '
 
 test_expect_success '--max-count all forms' '
 	test_must_fail git rev-list -1q HEAD 2>error &&
-	grep "not an integer" error &&
+	test_grep "not an integer" error &&
 	test_must_fail git rev-list --1 HEAD &&
 	test_must_fail git rev-list -n 1q HEAD 2>error &&
-	grep "not an integer" error &&
+	test_grep "not an integer" error &&
 
 	test_stdout_line_count = 1 git rev-list HEAD --max-count=1 &&
 	test_stdout_line_count = 1 git rev-list HEAD -1 &&
@@ -43,7 +43,7 @@ test_expect_success '--max-count all forms' '
 
 test_expect_success '--skip' '
 	test_must_fail git rev-list --skip 1q HEAD 2>error &&
-	grep "not an integer" error &&
+	test_grep "not an integer" error &&
 
 	test_stdout_line_count = 5 git rev-list HEAD --skip=0 &&
 	test_stdout_line_count = 2 git rev-list HEAD --skip=3 &&
diff --git a/t/t6006-rev-list-format.sh b/t/t6006-rev-list-format.sh
index 581984467d..d2648e1619 100755
--- a/t/t6006-rev-list-format.sh
+++ b/t/t6006-rev-list-format.sh
@@ -537,7 +537,7 @@ test_expect_success 'del LF before empty (1)' '
 test_expect_success 'del LF before empty (2)' '
 	git show -s --pretty=format:"%s%n%-b%nThanks%n" HEAD >actual &&
 	test_line_count = 6 actual &&
-	grep "^$" actual
+	test_grep "^$" actual
 '
 
 test_expect_success 'add LF before non-empty (1)' '
@@ -548,7 +548,7 @@ test_expect_success 'add LF before non-empty (1)' '
 test_expect_success 'add LF before non-empty (2)' '
 	git show -s --pretty=format:"%s%+b%nThanks%n" HEAD >actual &&
 	test_line_count = 6 actual &&
-	grep "^$" actual
+	test_grep "^$" actual
 '
 
 test_expect_success 'add SP before non-empty (1)' '
diff --git a/t/t6009-rev-list-parent.sh b/t/t6009-rev-list-parent.sh
index 9c9a8459af..fd6ee2eff8 100755
--- a/t/t6009-rev-list-parent.sh
+++ b/t/t6009-rev-list-parent.sh
@@ -64,10 +64,10 @@ test_expect_success 'setup roots, merges and octopuses' '
 
 test_expect_success 'parse --max-parents & --min-parents' '
 	test_must_fail git rev-list --max-parents=1q HEAD 2>error &&
-	grep "not an integer" error &&
+	test_grep "not an integer" error &&
 
 	test_must_fail git rev-list --min-parents=1q HEAD 2>error &&
-	grep "not an integer" error &&
+	test_grep "not an integer" error &&
 
 	git rev-list --max-parents=1 --min-parents=1 HEAD &&
 	git rev-list --max-parents=-1 --min-parents=-1 HEAD
diff --git a/t/t6020-bundle-misc.sh b/t/t6020-bundle-misc.sh
index 500c81b8a1..939d4214f4 100755
--- a/t/t6020-bundle-misc.sh
+++ b/t/t6020-bundle-misc.sh
@@ -612,7 +612,7 @@ test_expect_success 'cloning from filtered bundle has useful error' '
 		--all \
 		--filter=blob:none &&
 	test_must_fail git clone --bare partial.bdl partial 2>err &&
-	grep "cannot clone from filtered bundle" err
+	test_grep "cannot clone from filtered bundle" err
 '
 
 test_expect_success 'verify catches unreachable, broken prerequisites' '
@@ -644,13 +644,13 @@ test_expect_success 'verify catches unreachable, broken prerequisites' '
 		# Verify should fail
 		test_must_fail git bundle verify \
 			../clone-from/tip.bundle 2>err &&
-		grep "some prerequisite commits .* are not connected" err &&
+		test_grep "some prerequisite commits .* are not connected" err &&
 		test_line_count = 1 err &&
 
 		# Unbundling should fail
 		test_must_fail git bundle unbundle \
 			../clone-from/tip.bundle 2>err &&
-		grep "some prerequisite commits .* are not connected" err &&
+		test_grep "some prerequisite commits .* are not connected" err &&
 		test_line_count = 1 err
 	)
 '
@@ -658,7 +658,7 @@ test_expect_success 'verify catches unreachable, broken prerequisites' '
 test_expect_success 'bundle progress includes write phase' '
 	GIT_PROGRESS_DELAY=0 \
 		git bundle create --progress out.bundle --all 2>err &&
-	grep 'Writing' err
+	test_grep 'Writing' err
 '
 
 test_expect_success TTY 'create --quiet disables all bundle progress' '
@@ -670,7 +670,7 @@ test_expect_success TTY 'create --quiet disables all bundle progress' '
 test_expect_success 'bundle progress with --no-quiet' '
 	GIT_PROGRESS_DELAY=0 \
 		git bundle create --no-quiet out.bundle --all 2>err &&
-	grep "%" err
+	test_grep "%" err
 '
 
 test_expect_success 'create bundle with duplicate refnames' '
@@ -730,7 +730,7 @@ test_expect_success 'read bundle over stdin' '
 	git bundle create some.bundle HEAD &&
 
 	git bundle verify - <some.bundle 2>err &&
-	grep "<stdin> is okay" err &&
+	test_grep "<stdin> is okay" err &&
 
 	git bundle list-heads some.bundle >expect &&
 	git bundle list-heads - <some.bundle >actual &&
diff --git a/t/t6022-rev-list-missing.sh b/t/t6022-rev-list-missing.sh
index 08e92dd002..1e472a45af 100755
--- a/t/t6022-rev-list-missing.sh
+++ b/t/t6022-rev-list-missing.sh
@@ -68,7 +68,7 @@ do
 			allow-any)
 				;;
 			print)
-				grep ?$oid actual.raw &&
+				test_grep ?$oid actual.raw &&
 				echo ?$oid >>expect.raw
 				;;
 			esac &&
@@ -132,7 +132,7 @@ do
 				allow-any)
 					;;
 				print)
-					grep ?$oid actual.raw &&
+					test_grep ?$oid actual.raw &&
 					echo ?$oid >>expect.raw
 					;;
 				esac &&
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 081116220a..338df4f886 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -118,8 +118,8 @@ test_expect_success 'bisect fails if given any junk instead of revs' '
 test_expect_success 'bisect start without -- takes unknown arg as pathspec' '
 	git bisect reset &&
 	git bisect start foo bar &&
-	grep foo ".git/BISECT_NAMES" &&
-	grep bar ".git/BISECT_NAMES"
+	test_grep foo ".git/BISECT_NAMES" &&
+	test_grep bar ".git/BISECT_NAMES"
 '
 
 test_expect_success 'bisect reset: back in a branch checked out also elsewhere' '
@@ -258,7 +258,7 @@ test_expect_success 'bisect skip: successful result' '
 	git bisect start $HASH4 $HASH1 &&
 	git bisect skip &&
 	git bisect bad > my_bisect_log.txt &&
-	grep "$HASH2 is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep "$HASH2 is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 # $HASH1 is good, $HASH4 is bad, we skip $HASH3 and $HASH2
@@ -269,11 +269,11 @@ test_expect_success 'bisect skip: cannot tell between 3 commits' '
 	git bisect start $HASH4 $HASH1 &&
 	git bisect skip &&
 	test_expect_code 2 git bisect skip >my_bisect_log.txt &&
-	grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
-	! grep $HASH1 my_bisect_log.txt &&
-	grep $HASH2 my_bisect_log.txt &&
-	grep $HASH3 my_bisect_log.txt &&
-	grep $HASH4 my_bisect_log.txt
+	test_grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
+	test_grep ! $HASH1 my_bisect_log.txt &&
+	test_grep $HASH2 my_bisect_log.txt &&
+	test_grep $HASH3 my_bisect_log.txt &&
+	test_grep $HASH4 my_bisect_log.txt
 '
 
 # $HASH1 is good, $HASH4 is bad, we skip $HASH3
@@ -285,11 +285,11 @@ test_expect_success 'bisect skip: cannot tell between 2 commits' '
 	git bisect start $HASH4 $HASH1 &&
 	git bisect skip &&
 	test_expect_code 2 git bisect good >my_bisect_log.txt &&
-	grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
-	! grep $HASH1 my_bisect_log.txt &&
-	! grep $HASH2 my_bisect_log.txt &&
-	grep $HASH3 my_bisect_log.txt &&
-	grep $HASH4 my_bisect_log.txt
+	test_grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
+	test_grep ! $HASH1 my_bisect_log.txt &&
+	test_grep ! $HASH2 my_bisect_log.txt &&
+	test_grep $HASH3 my_bisect_log.txt &&
+	test_grep $HASH4 my_bisect_log.txt
 '
 
 # $HASH1 is good, $HASH4 is both skipped and bad, we skip $HASH3
@@ -304,11 +304,11 @@ test_expect_success 'bisect skip: with commit both bad and skipped' '
 	git bisect good $HASH1 &&
 	git bisect skip &&
 	test_expect_code 2 git bisect good >my_bisect_log.txt &&
-	grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
-	! grep $HASH1 my_bisect_log.txt &&
-	! grep $HASH2 my_bisect_log.txt &&
-	grep $HASH3 my_bisect_log.txt &&
-	grep $HASH4 my_bisect_log.txt
+	test_grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
+	test_grep ! $HASH1 my_bisect_log.txt &&
+	test_grep ! $HASH2 my_bisect_log.txt &&
+	test_grep $HASH3 my_bisect_log.txt &&
+	test_grep $HASH4 my_bisect_log.txt
 '
 
 test_bisect_run_args () {
@@ -439,7 +439,7 @@ test_expect_success '"git bisect run" simple case' '
 	git bisect good $HASH1 &&
 	git bisect bad $HASH4 &&
 	git bisect run ./test_script.sh >my_bisect_log.txt &&
-	grep "$HASH3 is the first '\''bad'\'' commit" my_bisect_log.txt &&
+	test_grep "$HASH3 is the first '\''bad'\'' commit" my_bisect_log.txt &&
 	git bisect reset
 '
 
@@ -449,7 +449,7 @@ test_expect_success '"git bisect run" simple case' '
 	git bisect good $HASH1 &&
 	git bisect bad $HASH4 &&
 	git bisect run printf "%s %s\n" reset --bisect-skip >my_bisect_log.txt &&
-	grep -e "reset --bisect-skip" my_bisect_log.txt &&
+	test_grep -e "reset --bisect-skip" my_bisect_log.txt &&
 	git bisect reset
 '
 
@@ -461,7 +461,7 @@ test_expect_success '"git bisect run" with more complex "git bisect start"' '
 	EOF
 	git bisect start $HASH4 $HASH1 &&
 	git bisect run ./test_script.sh >my_bisect_log.txt &&
-	grep "$HASH4 is the first '\''bad'\'' commit" my_bisect_log.txt &&
+	test_grep "$HASH4 is the first '\''bad'\'' commit" my_bisect_log.txt &&
 	git bisect reset
 '
 
@@ -474,7 +474,7 @@ test_expect_success 'bisect run accepts exit code 126 as bad' '
 	git bisect good $HASH1 &&
 	git bisect bad $HASH4 &&
 	git bisect run ./test_script.sh >my_bisect_log.txt &&
-	grep "$HASH3 is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep "$HASH3 is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 test_expect_success POSIXPERM 'bisect run fails with non-executable test script' '
@@ -485,7 +485,7 @@ test_expect_success POSIXPERM 'bisect run fails with non-executable test script'
 	git bisect good $HASH1 &&
 	git bisect bad $HASH4 &&
 	test_must_fail git bisect run ./not-executable.sh >my_bisect_log.txt &&
-	! grep "is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep ! "is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 test_expect_success 'bisect run accepts exit code 127 as bad' '
@@ -497,7 +497,7 @@ test_expect_success 'bisect run accepts exit code 127 as bad' '
 	git bisect good $HASH1 &&
 	git bisect bad $HASH4 &&
 	git bisect run ./test_script.sh >my_bisect_log.txt &&
-	grep "$HASH3 is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep "$HASH3 is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 test_expect_success 'bisect run fails with missing test script' '
@@ -507,7 +507,7 @@ test_expect_success 'bisect run fails with missing test script' '
 	git bisect good $HASH1 &&
 	git bisect bad $HASH4 &&
 	test_must_fail git bisect run ./does-not-exist.sh >my_bisect_log.txt &&
-	! grep "is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep ! "is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 # $HASH1 is good, $HASH5 is bad, we skip $HASH3
@@ -520,14 +520,14 @@ test_expect_success 'bisect skip: add line and then a new test' '
 	git bisect start $HASH5 $HASH1 &&
 	git bisect skip &&
 	git bisect good > my_bisect_log.txt &&
-	grep "$HASH5 is the first '\''bad'\'' commit" my_bisect_log.txt &&
+	test_grep "$HASH5 is the first '\''bad'\'' commit" my_bisect_log.txt &&
 	git bisect log > log_to_replay.txt &&
 	git bisect reset
 '
 
 test_expect_success 'bisect skip and bisect replay' '
 	git bisect replay log_to_replay.txt > my_bisect_log.txt &&
-	grep "$HASH5 is the first '\''bad'\'' commit" my_bisect_log.txt &&
+	test_grep "$HASH5 is the first '\''bad'\'' commit" my_bisect_log.txt &&
 	git bisect reset
 '
 
@@ -541,11 +541,11 @@ test_expect_success 'bisect run & skip: cannot tell between 2' '
 	EOF
 	git bisect start $HASH6 $HASH1 &&
 	test_expect_code 2 git bisect run ./test_script.sh >my_bisect_log.txt &&
-	grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
-	! grep $HASH3 my_bisect_log.txt &&
-	! grep $HASH6 my_bisect_log.txt &&
-	grep $HASH4 my_bisect_log.txt &&
-	grep $HASH5 my_bisect_log.txt
+	test_grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt &&
+	test_grep ! $HASH3 my_bisect_log.txt &&
+	test_grep ! $HASH6 my_bisect_log.txt &&
+	test_grep $HASH4 my_bisect_log.txt &&
+	test_grep $HASH5 my_bisect_log.txt
 '
 
 HASH7=
@@ -560,7 +560,7 @@ test_expect_success 'bisect run & skip: find first bad' '
 	EOF
 	git bisect start $HASH7 $HASH1 &&
 	git bisect run ./test_script.sh >my_bisect_log.txt &&
-	grep "$HASH6 is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep "$HASH6 is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 test_expect_success 'bisect skip only one range' '
@@ -569,7 +569,7 @@ test_expect_success 'bisect skip only one range' '
 	git bisect skip $HASH1..$HASH5 &&
 	test "$HASH6" = "$(git rev-parse --verify HEAD)" &&
 	test_must_fail git bisect bad > my_bisect_log.txt &&
-	grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt
+	test_grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt
 '
 
 test_expect_success 'bisect skip many ranges' '
@@ -578,7 +578,7 @@ test_expect_success 'bisect skip many ranges' '
 	git bisect skip $HASH2 $HASH2.. ..$HASH5 &&
 	test "$HASH6" = "$(git rev-parse --verify HEAD)" &&
 	test_must_fail git bisect bad > my_bisect_log.txt &&
-	grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt
+	test_grep "first '\''bad'\'' commit could be any of" my_bisect_log.txt
 '
 
 test_expect_success 'bisect starting with a detached HEAD' '
@@ -610,7 +610,7 @@ test_expect_success 'bisect does not create a "bisect" branch' '
 	rev_hash6=$(git rev-parse --verify HEAD) &&
 	test "$rev_hash6" = "$HASH6" &&
 	git bisect good > my_bisect_log.txt &&
-	grep "$HASH7 is the first '\''bad'\'' commit" my_bisect_log.txt &&
+	test_grep "$HASH7 is the first '\''bad'\'' commit" my_bisect_log.txt &&
 	git bisect reset &&
 	rev_hash6=$(git rev-parse --verify bisect) &&
 	test "$rev_hash6" = "$HASH6" &&
@@ -637,26 +637,26 @@ test_expect_success 'side branch creation' '
 test_expect_success 'good merge base when good and bad are siblings' '
 	git bisect start "$HASH7" "$SIDE_HASH7" > my_bisect_log.txt &&
 	test_grep "merge base must be tested" my_bisect_log.txt &&
-	grep $HASH4 my_bisect_log.txt &&
+	test_grep $HASH4 my_bisect_log.txt &&
 	git bisect good > my_bisect_log.txt &&
-	! grep "merge base must be tested" my_bisect_log.txt &&
-	grep $HASH6 my_bisect_log.txt &&
+	test_grep ! "merge base must be tested" my_bisect_log.txt &&
+	test_grep $HASH6 my_bisect_log.txt &&
 	git bisect reset
 '
 test_expect_success 'skipped merge base when good and bad are siblings' '
 	git bisect start "$SIDE_HASH7" "$HASH7" > my_bisect_log.txt &&
 	test_grep "merge base must be tested" my_bisect_log.txt &&
-	grep $HASH4 my_bisect_log.txt &&
+	test_grep $HASH4 my_bisect_log.txt &&
 	git bisect skip > my_bisect_log.txt 2>&1 &&
-	grep "warning" my_bisect_log.txt &&
-	grep $SIDE_HASH6 my_bisect_log.txt &&
+	test_grep "warning" my_bisect_log.txt &&
+	test_grep $SIDE_HASH6 my_bisect_log.txt &&
 	git bisect reset
 '
 
 test_expect_success 'bad merge base when good and bad are siblings' '
 	git bisect start "$HASH7" HEAD > my_bisect_log.txt &&
 	test_grep "merge base must be tested" my_bisect_log.txt &&
-	grep $HASH4 my_bisect_log.txt &&
+	test_grep $HASH4 my_bisect_log.txt &&
 	test_must_fail git bisect bad > my_bisect_log.txt 2>&1 &&
 	test_grep "merge base $HASH4 is bad" my_bisect_log.txt &&
 	test_grep "fixed between $HASH4 and \[$SIDE_HASH7\]" my_bisect_log.txt &&
@@ -686,8 +686,8 @@ test_expect_success 'many merge bases creation' '
 	B_HASH=$(git rev-parse --verify HEAD) &&
 	git merge-base --all "$A_HASH" "$B_HASH" > merge_bases.txt &&
 	test_line_count = 2 merge_bases.txt &&
-	grep "$HASH5" merge_bases.txt &&
-	grep "$SIDE_HASH5" merge_bases.txt
+	test_grep "$HASH5" merge_bases.txt &&
+	test_grep "$SIDE_HASH5" merge_bases.txt
 '
 
 # We want to automatically find the merge that
@@ -703,7 +703,7 @@ test_expect_success '"git bisect run --first-parent" simple case' '
 	git bisect good $HASH4 &&
 	git bisect bad $B_HASH &&
 	git bisect run ./test_script.sh >my_bisect_log.txt &&
-	grep "$B_HASH is the first '\''bad'\'' commit" my_bisect_log.txt &&
+	test_grep "$B_HASH is the first '\''bad'\'' commit" my_bisect_log.txt &&
 	git bisect reset &&
 	test_path_is_missing .git/BISECT_FIRST_PARENT
 '
@@ -715,11 +715,11 @@ test_expect_success 'good merge bases when good and bad are siblings' '
 	test_grep "merge base must be tested" my_bisect_log2.txt &&
 	{
 		{
-			grep "$SIDE_HASH5" my_bisect_log.txt &&
-			grep "$HASH5" my_bisect_log2.txt
+			test_grep "$SIDE_HASH5" my_bisect_log.txt &&
+			test_grep "$HASH5" my_bisect_log2.txt
 		} || {
-			grep "$SIDE_HASH5" my_bisect_log2.txt &&
-			grep "$HASH5" my_bisect_log.txt
+			test_grep "$SIDE_HASH5" my_bisect_log2.txt &&
+			test_grep "$HASH5" my_bisect_log.txt
 		}
 	} &&
 	git bisect reset
@@ -728,7 +728,7 @@ test_expect_success 'good merge bases when good and bad are siblings' '
 test_expect_success 'optimized merge base checks' '
 	git bisect start "$HASH7" "$SIDE_HASH7" > my_bisect_log.txt &&
 	test_grep "merge base must be tested" my_bisect_log.txt &&
-	grep "$HASH4" my_bisect_log.txt &&
+	test_grep "$HASH4" my_bisect_log.txt &&
 	git bisect good > my_bisect_log2.txt &&
 	test -f ".git/BISECT_ANCESTORS_OK" &&
 	test "$HASH6" = $(git rev-parse --verify HEAD) &&
@@ -777,7 +777,7 @@ test_expect_success 'restricting bisection on one dir' '
 	para1=$(git rev-parse --verify HEAD) &&
 	test "$para1" = "$PARA_HASH1" &&
 	git bisect bad > my_bisect_log.txt &&
-	grep "$PARA_HASH1 is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep "$PARA_HASH1 is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 test_expect_success 'restricting bisection on one dir and a file' '
@@ -795,7 +795,7 @@ test_expect_success 'restricting bisection on one dir and a file' '
 	para1=$(git rev-parse --verify HEAD) &&
 	test "$para1" = "$PARA_HASH1" &&
 	git bisect good > my_bisect_log.txt &&
-	grep "$PARA_HASH4 is the first '\''bad'\'' commit" my_bisect_log.txt
+	test_grep "$PARA_HASH4 is the first '\''bad'\'' commit" my_bisect_log.txt
 '
 
 test_expect_success 'skipping away from skipped commit' '
@@ -826,7 +826,7 @@ test_expect_success 'test bisection on bare repo - --no-checkout specified' '
 			"test \$(git rev-list BISECT_HEAD ^$HASH2 --max-count=1 | wc -l) = 0" \
 			>../nocheckout.log
 	) &&
-	grep "$HASH3 is the first '\''bad'\'' commit" nocheckout.log
+	test_grep "$HASH3 is the first '\''bad'\'' commit" nocheckout.log
 '
 
 
@@ -841,7 +841,7 @@ test_expect_success 'test bisection on bare repo - --no-checkout defaulted' '
 			"test \$(git rev-list BISECT_HEAD ^$HASH2 --max-count=1 | wc -l) = 0" \
 			>../defaulted.log
 	) &&
-	grep "$HASH3 is the first '\''bad'\'' commit" defaulted.log
+	test_grep "$HASH3 is the first '\''bad'\'' commit" defaulted.log
 '
 
 #
@@ -1031,21 +1031,21 @@ test_expect_success 'bisect start with one new and old' '
 	git bisect new $HASH4 &&
 	git bisect new &&
 	git bisect new >bisect_result &&
-	grep "$HASH2 is the first '\''new'\'' commit" bisect_result &&
+	test_grep "$HASH2 is the first '\''new'\'' commit" bisect_result &&
 	git bisect log >log_to_replay.txt &&
 	git bisect reset
 '
 
 test_expect_success 'bisect replay with old and new' '
 	git bisect replay log_to_replay.txt >bisect_result &&
-	grep "$HASH2 is the first '\''new'\'' commit" bisect_result &&
+	test_grep "$HASH2 is the first '\''new'\'' commit" bisect_result &&
 	git bisect reset
 '
 
 test_expect_success 'bisect replay with CRLF log' '
 	append_cr <log_to_replay.txt >log_to_replay_crlf.txt &&
 	git bisect replay log_to_replay_crlf.txt >bisect_result_crlf &&
-	grep "$HASH2 is the first '\''new'\'' commit" bisect_result_crlf &&
+	test_grep "$HASH2 is the first '\''new'\'' commit" bisect_result_crlf &&
 	git bisect reset
 '
 
@@ -1092,16 +1092,16 @@ test_expect_success 'bisect start with one term1 and term2' '
 test_expect_success 'bogus command does not start bisect' '
 	git bisect reset &&
 	test_must_fail git bisect --bisect-terms 1 2 2>out &&
-	! grep "You need to start" out &&
+	test_grep ! "You need to start" out &&
 	test_must_fail git bisect --bisect-terms 2>out &&
-	! grep "You need to start" out &&
-	grep "git bisect.*visualize" out &&
+	test_grep ! "You need to start" out &&
+	test_grep "git bisect.*visualize" out &&
 	git bisect reset
 '
 
 test_expect_success 'bisect replay with term1 and term2' '
 	git bisect replay log_to_replay.txt >bisect_result &&
-	grep "$HASH2 is the first '\''term1'\'' commit" bisect_result &&
+	test_grep "$HASH2 is the first '\''term1'\'' commit" bisect_result &&
 	git bisect reset
 '
 
@@ -1120,7 +1120,7 @@ test_expect_success 'bisect start term1 term2' '
 	git bisect start --term-new term1 --term-old term2 $HASH4 $HASH1 &&
 	git bisect term1 &&
 	git bisect term1 >bisect_result &&
-	grep "$HASH2 is the first '\''term1'\'' commit" bisect_result &&
+	test_grep "$HASH2 is the first '\''term1'\'' commit" bisect_result &&
 	git bisect log >log_to_replay.txt &&
 	git bisect reset
 '
@@ -1212,7 +1212,7 @@ test_expect_success 'bisect handles annotated tags' '
 	git bisect good tag-one &&
 	git bisect bad tag-two >output &&
 	bad=$(git rev-parse --verify tag-two^{commit}) &&
-	grep "$bad is the first '\''bad'\'' commit" output
+	test_grep "$bad is the first '\''bad'\'' commit" output
 '
 
 test_expect_success 'bisect run fails with exit code equals or greater than 128' '
@@ -1236,29 +1236,29 @@ test_expect_success 'bisect visualize with a filename with dash and space' '
 test_expect_success 'bisect state output with multiple good commits' '
 	git bisect reset &&
 	git bisect start >output &&
-	grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
+	test_grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
 	git bisect log >output &&
-	grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
+	test_grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
 	git bisect good "$HASH1" >output &&
-	grep "waiting for '\''bad'\'' commit, 1 '\''good'\'' commit known" output &&
+	test_grep "waiting for '\''bad'\'' commit, 1 '\''good'\'' commit known" output &&
 	git bisect log >output &&
-	grep "waiting for '\''bad'\'' commit, 1 '\''good'\'' commit known" output &&
+	test_grep "waiting for '\''bad'\'' commit, 1 '\''good'\'' commit known" output &&
 	git bisect good "$HASH2" >output &&
-	grep "waiting for '\''bad'\'' commit, 2 '\''good'\'' commits known" output &&
+	test_grep "waiting for '\''bad'\'' commit, 2 '\''good'\'' commits known" output &&
 	git bisect log >output &&
-	grep "waiting for '\''bad'\'' commit, 2 '\''good'\'' commits known" output
+	test_grep "waiting for '\''bad'\'' commit, 2 '\''good'\'' commits known" output
 '
 
 test_expect_success 'bisect state output with bad commit' '
 	git bisect reset &&
 	git bisect start >output &&
-	grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
+	test_grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
 	git bisect log >output &&
-	grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
+	test_grep "waiting for both '\''good'\'' and '\''bad'\'' commits" output &&
 	git bisect bad "$HASH4" >output &&
-	grep -F "waiting for '\''good'\'' commit(s), '\''bad'\'' commit known" output &&
+	test_grep -F "waiting for '\''good'\'' commit(s), '\''bad'\'' commit known" output &&
 	git bisect log >output &&
-	grep -F "waiting for '\''good'\'' commit(s), '\''bad'\'' commit known" output
+	test_grep -F "waiting for '\''good'\'' commit(s), '\''bad'\'' commit known" output
 '
 
 test_expect_success 'verify correct error message' '
@@ -1268,7 +1268,7 @@ test_expect_success 'verify correct error message' '
 	rm .git/BISECT*
 	EOF
 	test_must_fail git bisect run ./test_script.sh 2>error &&
-	grep "git bisect good.*exited with error code" error
+	test_grep "git bisect good.*exited with error code" error
 '
 
 test_done
diff --git a/t/t6040-tracking-info.sh b/t/t6040-tracking-info.sh
index 0242b5bf7a..369f810d85 100755
--- a/t/t6040-tracking-info.sh
+++ b/t/t6040-tracking-info.sh
@@ -275,7 +275,7 @@ test_expect_success '--set-upstream-to does not change branch' '
 	git branch --set-upstream-to main from-topic_2 &&
 	git config branch.from-main.merge > actual &&
 	git rev-parse from-topic_2 >actual2 &&
-	grep -q "^refs/heads/main$" actual &&
+	test_grep "^refs/heads/main$" actual &&
 	cmp expect2 actual2
 '
 
diff --git a/t/t6112-rev-list-filters-objects.sh b/t/t6112-rev-list-filters-objects.sh
index e0a825bccf..a1c244c32d 100755
--- a/t/t6112-rev-list-filters-objects.sh
+++ b/t/t6112-rev-list-filters-objects.sh
@@ -45,8 +45,8 @@ test_expect_success 'specify blob explicitly prevents filtering' '
 		 awk -f print_2.awk) &&
 
 	git -C r1 rev-list --objects --filter=blob:none HEAD $file_3 >observed &&
-	grep "$file_3" observed &&
-	! grep "$file_4" observed
+	test_grep "$file_3" observed &&
+	test_grep ! "$file_4" observed
 '
 
 test_expect_success 'verify emitted+omitted == all' '
@@ -324,7 +324,7 @@ test_expect_success 'rev-list W/ --missing=print and --missing=allow-any for tre
 
 	git -C r3.b rev-list --missing=allow-any --objects HEAD \
 		>objs 2>rev_list_err &&
-	! grep $TREE objs &&
+	test_grep ! $TREE objs &&
 	test_must_be_empty rev_list_err
 '
 
@@ -353,7 +353,7 @@ test_expect_success 'verify skipping tree iteration when not collecting omits' '
 	test_line_count = 2 actual &&
 
 	# Make sure no other trees were considered besides the root.
-	! grep "Skipping contents of tree [^.]" filter_trace &&
+	test_grep ! "Skipping contents of tree [^.]" filter_trace &&
 
 	# Try this again with "combine:". If both sub-filters are skipping
 	# trees, the composite filter should also skip trees. This is not
@@ -539,7 +539,7 @@ test_expect_success 'combine:... with more than two sub-filters' '
 		HEAD >actual &&
 
 	test_cmp expect actual &&
-	grep "Add to combine filter-spec: sparse:oid=main:p%3bat%25ter%2bn" \
+	test_grep "Add to combine filter-spec: sparse:oid=main:p%3bat%25ter%2bn" \
 		trace1 &&
 
 	# Repeat the above test, but this time, the characters to encode are in
@@ -551,7 +551,7 @@ test_expect_success 'combine:... with more than two sub-filters' '
 		HEAD >actual &&
 
 	test_cmp expect actual &&
-	grep "Add to combine filter-spec: sparse:oid=main:%5e%7epattern" \
+	test_grep "Add to combine filter-spec: sparse:oid=main:%5e%7epattern" \
 		trace2
 '
 
@@ -623,9 +623,9 @@ test_expect_success 'verify collecting omits in combined: filter' '
 	omitted_2=$(echo a     | git hash-object --stdin) &&
 	omitted_3=$(echo abcde | git hash-object --stdin) &&
 
-	grep "~$omitted_1" actual &&
-	grep "~$omitted_2" actual &&
-	grep "~$omitted_3" actual &&
+	test_grep "~$omitted_1" actual &&
+	test_grep "~$omitted_2" actual &&
+	test_grep "~$omitted_3" actual &&
 	test_line_count = 3 actual
 '
 
@@ -654,7 +654,7 @@ test_expect_success 'tree:<depth> which filters out blob but given as arg' '
 	blob_hash=$(git -C r4 rev-parse HEAD:subdir/bar) &&
 
 	git -C r4 rev-list --objects --filter=tree:1 HEAD $blob_hash >actual &&
-	grep ^$blob_hash actual
+	test_grep ^$blob_hash actual
 '
 
 # Delete some loose objects and use rev-list, but WITHOUT any filtering.
@@ -693,8 +693,8 @@ test_expect_success 'expand blob limit in protocol' '
 	git -C r2 config --local uploadpack.allowfilter 1 &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 clone \
 		--filter=blob:limit=1k "file://$(pwd)/r2" limit &&
-	! grep "blob:limit=1k" trace &&
-	grep "blob:limit=1024" trace
+	test_grep ! "blob:limit=1k" trace &&
+	test_grep "blob:limit=1024" trace
 '
 
 test_expect_success EXPENSIVE 'large sparse filter file ignored' '
diff --git a/t/t6115-rev-list-du.sh b/t/t6115-rev-list-du.sh
index 04c577dad6..b9650b80a4 100755
--- a/t/t6115-rev-list-du.sh
+++ b/t/t6115-rev-list-du.sh
@@ -61,13 +61,13 @@ check_du --all --objects --unpacked
 test_expect_success 'rev-list --disk-usage=human' '
 	git rev-list --objects HEAD --disk-usage=human >actual &&
 	disk_usage_slow --objects HEAD >actual_size &&
-	grep "$(cat actual_size) bytes" actual
+	test_grep "$(cat actual_size) bytes" actual
 '
 
 test_expect_success 'rev-list --disk-usage=human with bitmaps' '
 	git rev-list --objects HEAD --use-bitmap-index --disk-usage=human >actual &&
 	disk_usage_slow --objects HEAD >actual_size &&
-	grep "$(cat actual_size) bytes" actual
+	test_grep "$(cat actual_size) bytes" actual
 '
 
 test_expect_success 'rev-list use --disk-usage unproperly' '
diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
index 8ee3d2c37d..12b4fb307b 100755
--- a/t/t6120-describe.sh
+++ b/t/t6120-describe.sh
@@ -128,7 +128,7 @@ test_expect_success 'renaming tag A to Q locally produces a warning' "
 	warning: tag 'Q' is externally known as 'A'
 	EOF
 	test_cmp expected err &&
-	grep -E '^A-8-g[0-9a-f]+$' out
+	test_grep -E '^A-8-g[0-9a-f]+$' out
 "
 
 test_expect_success 'misnamed annotated tag forces long output' '
@@ -160,7 +160,7 @@ check_describe A-8-gHASH HEAD
 test_expect_success 'describe works from outside repo using --git-dir' '
 	git clone --bare "$TRASH_DIRECTORY" "$TRASH_DIRECTORY/bare" &&
 	git --git-dir "$TRASH_DIRECTORY/bare" describe >out &&
-	grep -E "^A-8-g[0-9a-f]+$" out
+	test_grep -E "^A-8-g[0-9a-f]+$" out
 '
 
 check_describe "A-8-gHASH" --dirty
@@ -170,7 +170,7 @@ test_expect_success 'describe --dirty with --work-tree' '
 		cd "$TEST_DIRECTORY" &&
 		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --dirty >"$TRASH_DIRECTORY/out"
 	) &&
-	grep -E "^A-8-g[0-9a-f]+$" out
+	test_grep -E "^A-8-g[0-9a-f]+$" out
 '
 
 test_expect_success 'set-up dirty work tree' '
@@ -183,7 +183,7 @@ test_expect_success 'describe --dirty with --work-tree (dirty)' '
 		cd "$TEST_DIRECTORY" &&
 		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --dirty >"$TRASH_DIRECTORY/out"
 	) &&
-	grep -E "^A-8-g[0-9a-f]+-dirty$" out &&
+	test_grep -E "^A-8-g[0-9a-f]+-dirty$" out &&
 	test_cmp expected out
 '
 
@@ -193,7 +193,7 @@ test_expect_success 'describe --dirty=.mod with --work-tree (dirty)' '
 		cd "$TEST_DIRECTORY" &&
 		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --dirty=.mod >"$TRASH_DIRECTORY/out"
 	) &&
-	grep -E "^A-8-g[0-9a-f]+.mod$" out &&
+	test_grep -E "^A-8-g[0-9a-f]+.mod$" out &&
 	test_cmp expected out
 '
 
@@ -377,7 +377,7 @@ test_expect_success 'describe chokes on severely broken submodules' '
 
 test_expect_success 'describe ignoring a broken submodule' '
 	git describe --broken >out &&
-	grep broken out
+	test_grep broken out
 '
 
 test_expect_success 'describe with --work-tree ignoring a broken submodule' '
@@ -386,7 +386,7 @@ test_expect_success 'describe with --work-tree ignoring a broken submodule' '
 		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --broken >"$TRASH_DIRECTORY/out"
 	) &&
 	test_when_finished "mv .git/modules/sub_moved .git/modules/sub1" &&
-	grep broken out
+	test_grep broken out
 '
 
 test_expect_success 'describe a blob at a directly tagged commit' '
diff --git a/t/t6200-fmt-merge-msg.sh b/t/t6200-fmt-merge-msg.sh
index 011e5df1e6..79fe1f20b4 100755
--- a/t/t6200-fmt-merge-msg.sh
+++ b/t/t6200-fmt-merge-msg.sh
@@ -125,20 +125,20 @@ test_expect_success GPG 'message for merging local tag signed by good key' '
 	git checkout main &&
 	git fetch . signed-good-tag &&
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}signed-good-tag${apos}" actual &&
-	grep "^signed-tag-msg" actual &&
-	grep "^# gpg: Signature made" actual &&
-	grep "^# gpg: Good signature from" actual
+	test_grep "^Merge tag ${apos}signed-good-tag${apos}" actual &&
+	test_grep "^signed-tag-msg" actual &&
+	test_grep "^# gpg: Signature made" actual &&
+	test_grep "^# gpg: Good signature from" actual
 '
 
 test_expect_success GPG 'message for merging local tag signed by unknown key' '
 	git checkout main &&
 	git fetch . signed-good-tag &&
 	GNUPGHOME=. git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}signed-good-tag${apos}" actual &&
-	grep "^signed-tag-msg" actual &&
-	grep "^# gpg: Signature made" actual &&
-	grep -E "^# gpg: Can${apos}t check signature: (public key not found|No public key)" actual
+	test_grep "^Merge tag ${apos}signed-good-tag${apos}" actual &&
+	test_grep "^signed-tag-msg" actual &&
+	test_grep "^# gpg: Signature made" actual &&
+	test_grep -E "^# gpg: Can${apos}t check signature: (public key not found|No public key)" actual
 '
 
 test_expect_success GPGSSH 'message for merging local tag signed by good ssh key' '
@@ -146,10 +146,10 @@ test_expect_success GPGSSH 'message for merging local tag signed by good ssh key
 	git checkout main &&
 	git fetch . signed-good-ssh-tag &&
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}signed-good-ssh-tag${apos}" actual &&
-	grep "^signed-ssh-tag-msg" actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+	test_grep "^Merge tag ${apos}signed-good-ssh-tag${apos}" actual &&
+	test_grep "^signed-ssh-tag-msg" actual &&
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual
 '
 
 test_expect_success GPGSSH 'message for merging local tag signed by unknown ssh key' '
@@ -157,11 +157,11 @@ test_expect_success GPGSSH 'message for merging local tag signed by unknown ssh
 	git checkout main &&
 	git fetch . signed-untrusted-ssh-tag &&
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}signed-untrusted-ssh-tag${apos}" actual &&
-	grep "^signed-ssh-tag-msg-untrusted" actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
-	grep "${GPGSSH_KEY_NOT_TRUSTED}" actual
+	test_grep "^Merge tag ${apos}signed-untrusted-ssh-tag${apos}" actual &&
+	test_grep "^signed-ssh-tag-msg-untrusted" actual &&
+	test_grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
+	test_grep "${GPGSSH_KEY_NOT_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag signed by expired ssh key' '
@@ -169,9 +169,9 @@ test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag sign
 	git checkout main &&
 	git fetch . expired-signed &&
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}expired-signed${apos}" actual &&
-	grep "^expired-signed" actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep "^Merge tag ${apos}expired-signed${apos}" actual &&
+	test_grep "^expired-signed" actual &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag signed by not yet valid ssh key' '
@@ -179,9 +179,9 @@ test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag sign
 	git checkout main &&
 	git fetch . notyetvalid-signed &&
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}notyetvalid-signed${apos}" actual &&
-	grep "^notyetvalid-signed" actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep "^Merge tag ${apos}notyetvalid-signed${apos}" actual &&
+	test_grep "^notyetvalid-signed" actual &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag signed by valid timeboxed ssh key' '
@@ -189,10 +189,10 @@ test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag sign
 	git checkout main &&
 	git fetch . timeboxedvalid-signed &&
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}timeboxedvalid-signed${apos}" actual &&
-	grep "^timeboxedvalid-signed" actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+	test_grep "^Merge tag ${apos}timeboxedvalid-signed${apos}" actual &&
+	test_grep "^timeboxedvalid-signed" actual &&
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag signed by invalid timeboxed ssh key' '
@@ -200,9 +200,9 @@ test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'message for merging local tag sign
 	git checkout main &&
 	git fetch . timeboxedinvalid-signed &&
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	grep "^Merge tag ${apos}timeboxedinvalid-signed${apos}" actual &&
-	grep "^timeboxedinvalid-signed" actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep "^Merge tag ${apos}timeboxedinvalid-signed${apos}" actual &&
+	test_grep "^timeboxedinvalid-signed" actual &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success 'message for merging external branch' '
@@ -651,21 +651,21 @@ test_expect_success 'merge --into-name=<name>' '
 	git show -s --format="%s" >full.0 &&
 	head -n1 full.0 >actual &&
 	# expect that HEAD is shown as-is
-	grep -e "Merge branch .side. into HEAD$" actual &&
+	test_grep -e "Merge branch .side. into HEAD$" actual &&
 
 	git reset --hard main &&
 	git merge --no-ff --into-name=main side &&
 	git show -s --format="%s" >full.1 &&
 	head -n1 full.1 >actual &&
 	# expect that we pretend to be merging to main, that is suppressed
-	grep -e "Merge branch .side.$" actual &&
+	test_grep -e "Merge branch .side.$" actual &&
 
 	git checkout -b throwaway main &&
 	git merge --no-ff --into-name=main side &&
 	git show -s --format="%s" >full.2 &&
 	head -n1 full.2 >actual &&
 	# expect that we pretend to be merging to main, that is suppressed
-	grep -e "Merge branch .side.$" actual
+	test_grep -e "Merge branch .side.$" actual
 '
 
 test_expect_success 'merge.suppressDest configuration' '
@@ -677,28 +677,28 @@ test_expect_success 'merge.suppressDest configuration' '
 
 	git -c merge.suppressDest="" fmt-merge-msg <.git/FETCH_HEAD >full.1 &&
 	head -n1 full.1 >actual &&
-	grep -e "Merge branch .side. into main" actual &&
+	test_grep -e "Merge branch .side. into main" actual &&
 
 	git -c merge.suppressDest="mast" fmt-merge-msg <.git/FETCH_HEAD >full.2 &&
 	head -n1 full.2 >actual &&
-	grep -e "Merge branch .side. into main$" actual &&
+	test_grep -e "Merge branch .side. into main$" actual &&
 
 	git -c merge.suppressDest="ma?*[rn]" fmt-merge-msg <.git/FETCH_HEAD >full.3 &&
 	head -n1 full.3 >actual &&
-	grep -e "Merge branch .side." actual &&
-	! grep -e " into main$" actual &&
+	test_grep -e "Merge branch .side." actual &&
+	test_grep ! -e " into main$" actual &&
 
 	git checkout --detach HEAD &&
 	git -c merge.suppressDest="main" fmt-merge-msg <.git/FETCH_HEAD >full.4 &&
 	head -n1 full.4 >actual &&
-	grep -e "Merge branch .side. into HEAD$" actual &&
+	test_grep -e "Merge branch .side. into HEAD$" actual &&
 
 	git -c merge.suppressDest="main" fmt-merge-msg \
 		--into-name=main <.git/FETCH_HEAD >full.5 &&
 	head -n1 full.5 >actual &&
-	grep -e "Merge branch .side." actual &&
-	! grep -e " into main$" actual &&
-	! grep -e " into HEAD$" actual
+	test_grep -e "Merge branch .side." actual &&
+	test_grep ! -e " into main$" actual &&
+	test_grep ! -e " into HEAD$" actual
 '
 
 test_done
diff --git a/t/t6402-merge-rename.sh b/t/t6402-merge-rename.sh
index ff00b74e9c..fb1595ae53 100755
--- a/t/t6402-merge-rename.sh
+++ b/t/t6402-merge-rename.sh
@@ -332,7 +332,7 @@ test_expect_success 'Same as previous, but merged other way' '
 	git checkout -q dir-in-way^0 &&
 	test_must_fail git merge --strategy=recursive renamed-file-has-no-conflicts >output 2>errors &&
 
-	! grep "error: refusing to lose untracked file at" errors &&
+	test_grep ! "error: refusing to lose untracked file at" errors &&
 	test_grep "CONFLICT (modify/delete): dir/file-in-the-way" output &&
 	test_grep "Auto-merging dir" output &&
 	test_grep "moving it to dir~renamed-file-has-no-conflicts instead" output &&
@@ -883,7 +883,7 @@ test_expect_success 'setup spurious "refusing to lose untracked" message' '
 test_expect_success 'no spurious "refusing to lose untracked" message' '
 	git checkout main^0 &&
 	test_must_fail git merge rename^0 2>errors.txt &&
-	! grep "refusing to lose untracked file" errors.txt
+	test_grep ! "refusing to lose untracked file" errors.txt
 '
 
 test_expect_success 'do not follow renames for empty files' '
diff --git a/t/t6403-merge-file.sh b/t/t6403-merge-file.sh
index 801284cf8f..dcc5c2ac99 100755
--- a/t/t6403-merge-file.sh
+++ b/t/t6403-merge-file.sh
@@ -356,7 +356,7 @@ test_expect_success "expected conflict markers" '
 test_expect_success 'binary files cannot be merged' '
 	test_must_fail git merge-file -p \
 		orig.txt "$TEST_DIRECTORY"/test-binary-1.png new1.txt 2> merge.err &&
-	grep "Cannot merge binary files" merge.err
+	test_grep "Cannot merge binary files" merge.err
 '
 
 test_expect_success 'binary files cannot be merged with --object-id' '
@@ -364,7 +364,7 @@ test_expect_success 'binary files cannot be merged with --object-id' '
 	git add orig.txt new1.txt test-binary-1.png &&
 	test_must_fail git merge-file --object-id \
 		:orig.txt :test-binary-1.png :new1.txt 2> merge.err &&
-	grep "Cannot merge binary files" merge.err
+	test_grep "Cannot merge binary files" merge.err
 '
 
 test_expect_success 'MERGE_ZEALOUS simplifies non-conflicts' '
@@ -539,7 +539,7 @@ test_expect_success 'conflict sections match existing line endings' '
 test_expect_success '--object-id fails without repository' '
 	empty="$(test_oid empty_blob)" &&
 	nongit test_must_fail git merge-file --object-id $empty $empty $empty 2>err &&
-	grep "not a git repository" err
+	test_grep "not a git repository" err
 '
 
 test_expect_success 'run in a linked worktree with --object-id' '
diff --git a/t/t6404-recursive-merge.sh b/t/t6404-recursive-merge.sh
index 346f3608b9..ce420fe1ac 100755
--- a/t/t6404-recursive-merge.sh
+++ b/t/t6404-recursive-merge.sh
@@ -109,7 +109,7 @@ test_expect_success 'refuse to merge binary files' '
 	git add binary-file &&
 	git commit -m binary2 &&
 	test_must_fail git merge F >merge_output &&
-	grep "Cannot merge binary files: binary-file (HEAD vs. F)" merge_output
+	test_grep "Cannot merge binary files: binary-file (HEAD vs. F)" merge_output
 '
 
 test_expect_success 'mark rename/delete as unmerged' '
diff --git a/t/t6406-merge-attr.sh b/t/t6406-merge-attr.sh
index 8f6fbef002..7f49c5908a 100755
--- a/t/t6406-merge-attr.sh
+++ b/t/t6406-merge-attr.sh
@@ -97,11 +97,11 @@ test_expect_success 'check merge result in index' '
 test_expect_success 'check merge result in working tree' '
 
 	git cat-file -p HEAD:binary >binary-orig &&
-	grep "<<<<<<<" text &&
+	test_grep "<<<<<<<" text &&
 	cmp binary-orig binary &&
-	! grep "<<<<<<<" union &&
-	grep Main union &&
-	grep Side union
+	test_grep ! "<<<<<<<" union &&
+	test_grep Main union &&
+	test_grep Side union
 
 '
 
@@ -112,9 +112,9 @@ test_expect_success 'retry the merge with longer context' '
 		s/ .*$//
 		p
 	}" >actual text &&
-	grep ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>" actual &&
-	grep "================================" actual &&
-	grep "<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<" actual
+	test_grep ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>" actual &&
+	test_grep "================================" actual &&
+	test_grep "<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<" actual
 '
 
 test_expect_success 'invalid conflict-marker-size 3a' '
@@ -193,7 +193,7 @@ test_expect_success !WINDOWS 'custom merge driver that is killed with a signal'
 	>./please-abort &&
 	echo "* merge=custom" >.gitattributes &&
 	test_expect_code 2 git merge main 2>err &&
-	grep "^error: failed to execute internal merge" err &&
+	test_grep "^error: failed to execute internal merge" err &&
 	git ls-files -u >output &&
 	git diff --name-only HEAD >>output &&
 	test_must_be_empty output
@@ -260,7 +260,7 @@ test_expect_success 'binary files with union attribute' '
 	git commit -am two &&
 
 	test_must_fail git merge bin-main >output &&
-	grep -i "warning.*cannot merge.*HEAD vs. bin-main" output
+	test_grep -i "warning.*cannot merge.*HEAD vs. bin-main" output
 '
 
 test_expect_success !WINDOWS 'custom merge driver that is killed with a signal on recursive merge' '
@@ -297,7 +297,7 @@ test_expect_success !WINDOWS 'custom merge driver that is killed with a signal o
 	>./please-abort &&
 	echo "* merge=custom" >.gitattributes &&
 	test_expect_code 2 git merge recursive-a 2>err &&
-	grep "error: failed to execute internal merge" err &&
+	test_grep "error: failed to execute internal merge" err &&
 	git ls-files -u >output &&
 	git diff --name-only HEAD >>output &&
 	test_must_be_empty output
diff --git a/t/t6417-merge-ours-theirs.sh b/t/t6417-merge-ours-theirs.sh
index 62d1406119..9486251399 100755
--- a/t/t6417-merge-ours-theirs.sh
+++ b/t/t6417-merge-ours-theirs.sh
@@ -26,31 +26,31 @@ test_expect_success setup '
 test_expect_success 'plain recursive - should conflict' '
 	git reset --hard main &&
 	test_must_fail git merge -s recursive side &&
-	grep nine file &&
-	grep nueve file &&
-	! grep 9 file &&
-	grep one file &&
-	! grep 1 file
+	test_grep nine file &&
+	test_grep nueve file &&
+	test_grep ! 9 file &&
+	test_grep one file &&
+	test_grep ! 1 file
 '
 
 test_expect_success 'recursive favouring theirs' '
 	git reset --hard main &&
 	git merge -s recursive -Xtheirs side &&
-	! grep nine file &&
-	grep nueve file &&
-	! grep 9 file &&
-	grep one file &&
-	! grep 1 file
+	test_grep ! nine file &&
+	test_grep nueve file &&
+	test_grep ! 9 file &&
+	test_grep one file &&
+	test_grep ! 1 file
 '
 
 test_expect_success 'recursive favouring ours' '
 	git reset --hard main &&
 	git merge -s recursive -X ours side &&
-	grep nine file &&
-	! grep nueve file &&
-	! grep 9 file &&
-	grep one file &&
-	! grep 1 file
+	test_grep nine file &&
+	test_grep ! nueve file &&
+	test_grep ! 9 file &&
+	test_grep one file &&
+	test_grep ! 1 file
 '
 
 test_expect_success 'binary file with -Xours/-Xtheirs' '
diff --git a/t/t6418-merge-text-auto.sh b/t/t6418-merge-text-auto.sh
index 41288a60ce..c86a1bedd5 100755
--- a/t/t6418-merge-text-auto.sh
+++ b/t/t6418-merge-text-auto.sh
@@ -226,7 +226,7 @@ test_expect_success 'rename/delete vs. renormalization' '
 		git checkout rename^0 &&
 		test_must_fail git -c merge.renormalize=true merge nuke >out &&
 
-		grep "rename/delete" out
+		test_grep "rename/delete" out
 	)
 '
 
diff --git a/t/t6422-merge-rename-corner-cases.sh b/t/t6422-merge-rename-corner-cases.sh
index e18d5a227d..d1f1de14e7 100755
--- a/t/t6422-merge-rename-corner-cases.sh
+++ b/t/t6422-merge-rename-corner-cases.sh
@@ -916,8 +916,8 @@ test_expect_success 'rad-check: rename/add/delete conflict' '
 		# bar should have two-way merged contents of the different
 		# versions of bar; check that content from both sides is
 		# present.
-		grep original bar &&
-		grep different bar
+		test_grep original bar &&
+		test_grep different bar
 	)
 '
 
@@ -991,8 +991,8 @@ test_expect_success 'rrdd-check: rename/rename(2to1)/delete/delete conflict' '
 		# baz should have two-way merged contents of the original
 		# contents of foo and bar; check that content from both sides
 		# is present.
-		grep foo baz &&
-		grep bar baz
+		test_grep foo baz &&
+		test_grep bar baz
 	)
 '
 
diff --git a/t/t6423-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index 53535a8ebf..5a12db1f8f 100755
--- a/t/t6423-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh
@@ -1113,7 +1113,7 @@ test_expect_success '5c: Transitive rename would cause rename/rename/rename/add/
 		test_cmp expect actual &&
 		test_path_is_missing x/d &&
 		test_path_is_file y/d &&
-		grep -q "<<<<" y/d  # conflict markers should be present
+		test_grep "<<<<" y/d  # conflict markers should be present
 	)
 '
 
@@ -2841,10 +2841,10 @@ test_expect_success '9e: N-to-1 whammo' '
 
 		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		grep "CONFLICT (implicit dir rename): Cannot map more than one path to combined/yo" out >error_line &&
-		grep -q dir1/yo error_line &&
-		grep -q dir2/yo error_line &&
-		grep -q dir3/yo error_line &&
-		grep -q dirN/yo error_line &&
+		test_grep dir1/yo error_line &&
+		test_grep dir2/yo error_line &&
+		test_grep dir3/yo error_line &&
+		test_grep dirN/yo error_line &&
 
 		git ls-files -s >out &&
 		test_line_count = 16 out &&
@@ -3578,7 +3578,7 @@ test_expect_success '11b: Avoid losing dirty file involved in directory rename'
 		test_path_is_missing .git/MERGE_HEAD &&
 		test_grep "error: Your local changes to the following files would be overwritten by merge" err &&
 
-		grep -q stuff z/c &&
+		test_grep stuff z/c &&
 		test_seq 1 10 >expected &&
 		echo stuff >>expected &&
 		test_cmp expected z/c
@@ -3636,7 +3636,7 @@ test_expect_success '11c: Avoid losing not-uptodate with rename + D/F conflict'
 		test_path_is_missing .git/MERGE_HEAD &&
 		test_grep "error: Your local changes to the following files would be overwritten by merge" err &&
 
-		grep -q stuff y/c &&
+		test_grep stuff y/c &&
 		test_seq 1 10 >expected &&
 		echo stuff >>expected &&
 		test_cmp expected y/c &&
@@ -3705,7 +3705,7 @@ test_expect_success '11d: Avoid losing not-uptodate with rename + D/F conflict'
 		test_path_is_missing .git/MERGE_HEAD &&
 		test_grep "error: Your local changes to the following files would be overwritten by merge" err &&
 
-		grep -q stuff z/c &&
+		test_grep stuff z/c &&
 		test_seq 1 10 >expected &&
 		echo stuff >>expected &&
 		test_cmp expected z/c
@@ -4779,7 +4779,7 @@ test_expect_success '12i: Directory rename causes rename-to-self' '
 
 		test_must_fail git -c merge.directoryRenames=conflict merge -s recursive B^0 >out &&
 
-		grep "CONFLICT (implicit dir rename).*source/bar in the way" out &&
+		test_grep "CONFLICT (implicit dir rename).*source/bar in the way" out &&
 		test_path_is_missing source/bar &&
 		test_path_is_file source/subdir/bar &&
 		test_path_is_file source/baz &&
@@ -4920,7 +4920,7 @@ test_expect_success '12j: Directory rename to root causes rename-to-self' '
 		# error about there being a file in the way.
 
 		test_must_fail git -c merge.directoryRenames=conflict merge -s recursive B^0 >out &&
-		grep "CONFLICT (implicit dir rename).*bar in the way" out &&
+		test_grep "CONFLICT (implicit dir rename).*bar in the way" out &&
 
 		test_path_is_missing bar &&
 		test_path_is_file subdir/bar &&
@@ -4999,7 +4999,7 @@ test_expect_success '12k: Directory rename with sibling causes rename-to-self' '
 		# error about there being a file in the way.
 
 		test_must_fail git -c merge.directoryRenames=conflict merge -s recursive B^0 >out &&
-		grep "CONFLICT (implicit dir rename).*dirA/bar in the way" out &&
+		test_grep "CONFLICT (implicit dir rename).*dirA/bar in the way" out &&
 
 		test_path_is_missing dirA/bar &&
 		test_path_is_file dirB/bar &&
@@ -5402,7 +5402,7 @@ test_expect_success '12o: Directory rename hits other rename source; file still
 		test_stdout_line_count = 1 git ls-files -s B/stuff &&
 		test_stdout_line_count = 1 git ls-files -s D/file2 &&
 
-		grep "CONFLICT (implicit dir rename).*Existing file/dir at A/file1 in the way" out &&
+		test_grep "CONFLICT (implicit dir rename).*Existing file/dir at A/file1 in the way" out &&
 		test_stdout_line_count = 1 git ls-files -s C/file1
 	)
 '
@@ -5489,7 +5489,7 @@ test_expect_success '12p: Directory rename hits other rename source; file still
 		test_stdout_line_count = 1 git ls-files -s B/stuff &&
 		test_stdout_line_count = 1 git ls-files -s D/file2 &&
 
-		grep "CONFLICT (implicit dir rename).*Existing file/dir at A/file1 in the way" out &&
+		test_grep "CONFLICT (implicit dir rename).*Existing file/dir at A/file1 in the way" out &&
 		test_stdout_line_count = 1 git ls-files -s C/file1
 	)
 '
@@ -5570,8 +5570,8 @@ test_expect_success '12q: Directory rename hits other rename source; file remove
 
 		test_must_fail git -c merge.directoryRenames=conflict merge -s recursive B^0 >out &&
 
-		grep "CONFLICT (rename/delete).*A/file1.*D/file2" out &&
-		grep "CONFLICT (implicit dir rename).*Existing file/dir at A/file1 in the way" out &&
+		test_grep "CONFLICT (rename/delete).*A/file1.*D/file2" out &&
+		test_grep "CONFLICT (implicit dir rename).*Existing file/dir at A/file1 in the way" out &&
 
 		test_stdout_line_count = 6 git ls-files -s &&
 		test_stdout_line_count = 1 git ls-files -s A/other &&
@@ -5586,7 +5586,7 @@ test_expect_success '12q: Directory rename hits other rename source; file remove
 		# the dir rename of C/file1 -> A/file1 would mean modifying
 		# the code so that renames do not adjust both their source
 		# and target paths in all cases.
-		! grep "CONFLICT (file location)" out &&
+		test_grep ! "CONFLICT (file location)" out &&
 		test_stdout_line_count = 1 git ls-files -s C/file1
 	)
 '
@@ -5652,8 +5652,8 @@ test_expect_success '13a(conflict): messages for newly added files' '
 		test_grep CONFLICT..file.location.*z/d.added.in.B^0.*y/d out &&
 
 		git ls-files >paths &&
-		! grep z/ paths &&
-		grep "y/[de]" paths &&
+		test_grep ! z/ paths &&
+		test_grep "y/[de]" paths &&
 
 		test_path_is_missing z/d &&
 		test_path_is_file    y/d &&
@@ -5676,8 +5676,8 @@ test_expect_success '13a(info): messages for newly added files' '
 		test_grep Path.updated:.*z/d.added.in.B^0.*y/d out &&
 
 		git ls-files >paths &&
-		! grep z/ paths &&
-		grep "y/[de]" paths &&
+		test_grep ! z/ paths &&
+		test_grep "y/[de]" paths &&
 
 		test_path_is_missing z/d &&
 		test_path_is_file    y/d &&
@@ -5742,8 +5742,8 @@ test_expect_success '13b(conflict): messages for transitive rename with conflict
 		test_grep CONFLICT..file.location.*x/d.renamed.to.z/d.*moved.to.y/d out &&
 
 		git ls-files >paths &&
-		! grep z/ paths &&
-		grep "y/d" paths &&
+		test_grep ! z/ paths &&
+		test_grep "y/d" paths &&
 
 		test_path_is_missing z/d &&
 		test_path_is_file    y/d
@@ -5764,8 +5764,8 @@ test_expect_success '13b(info): messages for transitive rename with conflicted c
 		test_grep Path.updated:.*x/d.renamed.to.z/d.in.B^0.*moving.it.to.y/d out &&
 
 		git ls-files >paths &&
-		! grep z/ paths &&
-		grep "y/d" paths &&
+		test_grep ! z/ paths &&
+		test_grep "y/d" paths &&
 
 		test_path_is_missing z/d &&
 		test_path_is_file    y/d
@@ -5827,8 +5827,8 @@ test_expect_success '13c(conflict): messages for rename/rename(1to1) via transit
 		test_grep CONFLICT..file.location.*x/d.renamed.to.z/d.*moved.to.y/d out &&
 
 		git ls-files >paths &&
-		! grep z/ paths &&
-		grep "y/d" paths &&
+		test_grep ! z/ paths &&
+		test_grep "y/d" paths &&
 
 		test_path_is_missing z/d &&
 		test_path_is_file    y/d
@@ -5848,8 +5848,8 @@ test_expect_success '13c(info): messages for rename/rename(1to1) via transitive
 		test_grep Path.updated:.*x/d.renamed.to.z/d.in.B^0.*moving.it.to.y/d out &&
 
 		git ls-files >paths &&
-		! grep z/ paths &&
-		grep "y/d" paths &&
+		test_grep ! z/ paths &&
+		test_grep "y/d" paths &&
 
 		test_path_is_missing z/d &&
 		test_path_is_file    y/d
@@ -5917,9 +5917,9 @@ test_expect_success '13d(conflict): messages for rename/rename(1to1) via dual tr
 		test_grep CONFLICT..file.location.*a/y.renamed.to.c/y.*moved.to.d/y out &&
 
 		git ls-files >paths &&
-		! grep b/ paths &&
-		! grep c/ paths &&
-		grep "d/y" paths &&
+		test_grep ! b/ paths &&
+		test_grep ! c/ paths &&
+		test_grep "d/y" paths &&
 
 		test_path_is_missing b/y &&
 		test_path_is_missing c/y &&
@@ -5941,9 +5941,9 @@ test_expect_success '13d(info): messages for rename/rename(1to1) via dual transi
 		test_grep Path.updated.*a/y.renamed.to.c/y.*moving.it.to.d/y out &&
 
 		git ls-files >paths &&
-		! grep b/ paths &&
-		! grep c/ paths &&
-		grep "d/y" paths &&
+		test_grep ! b/ paths &&
+		test_grep ! c/ paths &&
+		test_grep "d/y" paths &&
 
 		test_path_is_missing b/y &&
 		test_path_is_missing c/y &&
@@ -6058,8 +6058,8 @@ test_expect_success '13e: directory rename detection in recursive case' '
 		test_must_be_empty err &&
 
 		git ls-files >paths &&
-		! grep a/x paths &&
-		grep b/x paths
+		test_grep ! a/x paths &&
+		test_grep b/x paths
 	)
 '
 
diff --git a/t/t6424-merge-unrelated-index-changes.sh b/t/t6424-merge-unrelated-index-changes.sh
index ddc7524f6c..12e58bc335 100755
--- a/t/t6424-merge-unrelated-index-changes.sh
+++ b/t/t6424-merge-unrelated-index-changes.sh
@@ -298,9 +298,9 @@ test_expect_success 'with multiple strategies, recursive or ort failure do not e
 
 	test_must_fail git merge -s ort -s octopus C^0 >output 2>&1 &&
 
-	grep "Trying merge strategy ort..." output &&
-	grep "Trying merge strategy octopus..." output &&
-	grep "No merge strategy handled the merge." output &&
+	test_grep "Trying merge strategy ort..." output &&
+	test_grep "Trying merge strategy octopus..." output &&
+	test_grep "No merge strategy handled the merge." output &&
 
 	# Changes to "a" should remain staged
 	git rev-parse :a >actual &&
diff --git a/t/t6427-diff3-conflict-markers.sh b/t/t6427-diff3-conflict-markers.sh
index 57569c4f4b..818550bc95 100755
--- a/t/t6427-diff3-conflict-markers.sh
+++ b/t/t6427-diff3-conflict-markers.sh
@@ -39,7 +39,7 @@ test_expect_success 'check no merge base' '
 
 		test_must_fail git -c merge.conflictstyle=diff3 merge --allow-unrelated-histories -s recursive R^0 &&
 
-		grep "|||||| empty tree" content
+		test_grep "|||||| empty tree" content
 	)
 '
 
@@ -97,7 +97,7 @@ test_expect_success 'check unique merge base' '
 
 		test_must_fail git -c merge.conflictstyle=diff3 merge -s recursive R^0 &&
 
-		grep "|||||| $MAIN:content" renamed
+		test_grep "|||||| $MAIN:content" renamed
 	)
 '
 
@@ -185,7 +185,7 @@ test_expect_success 'check multiple merge bases' '
 
 		test_must_fail git -c merge.conflictstyle=diff3 merge -s recursive R^0 &&
 
-		grep "|||||| merged common ancestors:content" renamed
+		test_grep "|||||| merged common ancestors:content" renamed
 	)
 '
 
@@ -198,7 +198,7 @@ test_expect_success 'rebase --merge describes parent of commit being picked' '
 		git checkout -b side HEAD^ &&
 		test_commit side file &&
 		test_must_fail git -c merge.conflictstyle=diff3 rebase --merge main &&
-		grep "||||||| parent of" file
+		test_grep "||||||| parent of" file
 	)
 '
 
@@ -207,7 +207,7 @@ test_expect_success 'rebase --apply describes fake ancestor base' '
 		cd rebase &&
 		git rebase --abort &&
 		test_must_fail git -c merge.conflictstyle=diff3 rebase --apply main &&
-		grep "||||||| constructed fake ancestor" file
+		test_grep "||||||| constructed fake ancestor" file
 	)
 '
 
diff --git a/t/t6432-merge-recursive-space-options.sh b/t/t6432-merge-recursive-space-options.sh
index db4b77e63d..110b48cb67 100755
--- a/t/t6432-merge-recursive-space-options.sh
+++ b/t/t6432-merge-recursive-space-options.sh
@@ -109,7 +109,7 @@ test_expect_success 'naive merge fails' '
 	git read-tree --reset -u HEAD &&
 	test_must_fail git merge-recursive HEAD^ -- HEAD remote &&
 	test_must_fail git update-index --refresh &&
-	grep "<<<<<<" text.txt
+	test_grep "<<<<<<" text.txt
 '
 
 test_expect_success '--ignore-space-change makes merge succeed' '
@@ -123,7 +123,7 @@ test_expect_success 'naive cherry-pick fails' '
 	git read-tree --reset -u HEAD &&
 	test_must_fail git cherry-pick remote &&
 	test_must_fail git update-index --refresh &&
-	grep "<<<<<<" text.txt
+	test_grep "<<<<<<" text.txt
 '
 
 test_expect_success '-Xignore-space-change makes cherry-pick succeed' '
diff --git a/t/t6436-merge-overwrite.sh b/t/t6436-merge-overwrite.sh
index 70b5d2d694..5e39a15fac 100755
--- a/t/t6436-merge-overwrite.sh
+++ b/t/t6436-merge-overwrite.sh
@@ -189,10 +189,10 @@ test_expect_success 'set up unborn branch and content' '
 
 test_expect_success 'will not clobber WT/index when merging into unborn' '
 	git merge main &&
-	grep foo tracked-file &&
+	test_grep foo tracked-file &&
 	git show :tracked-file >expect &&
-	grep foo expect &&
-	grep bar untracked-file
+	test_grep foo expect &&
+	test_grep bar untracked-file
 '
 
 test_done
diff --git a/t/t6437-submodule-merge.sh b/t/t6437-submodule-merge.sh
index a564758f52..0c5264c5e3 100755
--- a/t/t6437-submodule-merge.sh
+++ b/t/t6437-submodule-merge.sh
@@ -111,7 +111,7 @@ test_expect_success 'merging should conflict for non fast-forward' '
 	 git checkout -b test-nonforward-a b &&
 	 test_must_fail git merge c 2>actual &&
 	 sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
-	 grep "$sub_expect" actual
+	 test_grep "$sub_expect" actual
 	 )
 '
 
@@ -148,7 +148,7 @@ test_expect_success 'merging should conflict for non fast-forward (resolution ex
 	  git rev-parse --short sub-d > ../expect) &&
 	  test_must_fail git merge c >actual 2>sub-actual &&
 	  sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
-	  grep "$sub_expect" sub-actual &&
+	  test_grep "$sub_expect" sub-actual &&
 	 grep $(cat expect) actual > /dev/null &&
 	 git reset --hard)
 '
@@ -164,7 +164,7 @@ test_expect_success 'merging should fail for ambiguous common parent' '
 	 ) &&
 	test_must_fail git merge c >actual 2>sub-actual &&
 	sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
-	grep "$sub_expect" sub-actual &&
+	test_grep "$sub_expect" sub-actual &&
 	grep $(cat expect1) actual > /dev/null &&
 	grep $(cat expect2) actual > /dev/null &&
 	git reset --hard)
@@ -207,7 +207,7 @@ test_expect_success 'merging should fail for changes that are backwards' '
 	git checkout -b test-backward e &&
 	test_must_fail git merge f 2>actual &&
 	sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-d)" &&
-	grep "$sub_expect" actual
+	test_grep "$sub_expect" actual
 	)
 '
 
@@ -356,7 +356,7 @@ test_expect_success 'file/submodule conflict' '
 		# directory, though, so just grep for its content in all
 		# files, and ignore "grep: path: Is a directory" message
 		echo Checking if contents from B:path showed up anywhere &&
-		grep -q content * 2>/dev/null
+		grep -q content * 2>/dev/null # lint-ok: glob arg breaks test_grep
 	)
 '
 
@@ -513,7 +513,7 @@ test_expect_success 'merging should fail with no merge base' '
 	git commit -m "b" &&
 	test_must_fail git merge a 2>actual &&
 	sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short HEAD^1)" &&
-	grep "$sub_expect" actual
+	test_grep "$sub_expect" actual
 	)
 '
 
diff --git a/t/t6500-gc.sh b/t/t6500-gc.sh
index ea9aaad470..3ee4b18d88 100755
--- a/t/t6500-gc.sh
+++ b/t/t6500-gc.sh
@@ -176,15 +176,15 @@ test_expect_success 'gc.reflogExpire{Unreachable,}=never skips "expire" via "gc"
 
 	# Check that git-pack-refs is run as a sanity check (done via
 	# gc_before_repack()) but that git-expire is not.
-	grep -E "^trace: (built-in|exec|run_command): git pack-refs --" trace.out &&
-	! grep -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
+	test_grep -E "^trace: (built-in|exec|run_command): git pack-refs --" trace.out &&
+	test_grep ! -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
 '
 
 test_expect_success 'one of gc.reflogExpire{Unreachable,}=never does not skip "expire" via "gc"' '
 	>trace.out &&
 	test_config gc.reflogExpire never &&
 	GIT_TRACE=$(pwd)/trace.out git gc &&
-	grep -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
+	test_grep -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
 '
 
 test_expect_success 'gc.repackFilter launches repack with a filter' '
@@ -196,7 +196,7 @@ test_expect_success 'gc.repackFilter launches repack with a filter' '
 	GIT_TRACE=$(pwd)/trace.out git -C bare.git -c gc.repackFilter=blob:none \
 		-c repack.writeBitmaps=false -c gc.cruftPacks=false gc &&
 	test_stdout_line_count = 2 ls bare.git/objects/pack/*.pack &&
-	grep -E "^trace: (built-in|exec|run_command): git repack .* --filter=blob:none ?.*" trace.out
+	test_grep -E "^trace: (built-in|exec|run_command): git repack .* --filter=blob:none ?.*" trace.out
 '
 
 test_expect_success 'gc.repackFilterTo store filtered out objects' '
diff --git a/t/t6600-test-reach.sh b/t/t6600-test-reach.sh
index b5b314e570..ee46d66b84 100755
--- a/t/t6600-test-reach.sh
+++ b/t/t6600-test-reach.sh
@@ -958,13 +958,13 @@ test_expect_success 'merge-base without --all is one of --all results' '
 	git merge-base --all commit-5-7 commit-4-8 commit-6-6 commit-8-3 >all &&
 	git merge-base commit-5-7 commit-4-8 commit-6-6 commit-8-3 >single &&
 	test_line_count = 1 single &&
-	grep -F -f single all &&
+	test_grep -F -f single all &&
 
 	cp commit-graph-half .git/objects/info/commit-graph &&
 	git merge-base --all commit-5-7 commit-4-8 commit-6-6 commit-8-3 >all &&
 	git merge-base commit-5-7 commit-4-8 commit-6-6 commit-8-3 >single &&
 	test_line_count = 1 single &&
-	grep -F -f single all
+	test_grep -F -f single all
 '
 
 test_done
diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index 920479e925..7cf4aa5ba1 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -46,7 +46,7 @@ test_expect_success 'commiting the change' '
 
 test_expect_success 'checking the commit' '
 	git diff-tree -r -M --name-status  HEAD^ HEAD >actual &&
-	grep "^R100..*path0/COPYING..*path1/COPYING" actual
+	test_grep "^R100..*path0/COPYING..*path1/COPYING" actual
 '
 
 test_expect_success 'moving the file back into subdirectory' '
@@ -60,7 +60,7 @@ test_expect_success 'commiting the change' '
 
 test_expect_success 'checking the commit' '
 	git diff-tree -r -M --name-status  HEAD^ HEAD >actual &&
-	grep "^R100..*path1/COPYING..*path0/COPYING" actual
+	test_grep "^R100..*path1/COPYING..*path0/COPYING" actual
 '
 
 test_expect_success 'mv --dry-run does not move file' '
@@ -147,8 +147,8 @@ test_expect_success 'commiting the change' '
 
 test_expect_success 'checking the commit' '
 	git diff-tree -r -M --name-status  HEAD^ HEAD >actual &&
-	grep "^R100..*path0/COPYING..*path2/COPYING" actual &&
-	grep "^R100..*path0/README..*path2/README" actual
+	test_grep "^R100..*path0/COPYING..*path2/COPYING" actual &&
+	test_grep "^R100..*path0/README..*path2/README" actual
 '
 
 test_expect_success 'succeed when source is a prefix of destination' '
@@ -165,8 +165,8 @@ test_expect_success 'commiting the change' '
 
 test_expect_success 'checking the commit' '
 	git diff-tree -r -M --name-status  HEAD^ HEAD >actual &&
-	grep "^R100..*path2/COPYING..*path1/path2/COPYING" actual &&
-	grep "^R100..*path2/README..*path1/path2/README" actual
+	test_grep "^R100..*path2/COPYING..*path1/path2/COPYING" actual &&
+	test_grep "^R100..*path2/README..*path1/path2/README" actual
 '
 
 test_expect_success 'do not move directory over existing directory' '
@@ -200,7 +200,7 @@ test_expect_success "Michael Cassar's test case" '
 
 	T=$(git write-tree) &&
 	git ls-tree -r $T >out &&
-	grep partA/outline.txt out
+	test_grep partA/outline.txt out
 '
 
 rm -fr papers partA path?
@@ -504,7 +504,7 @@ test_expect_success 'mv -k does not accidentally destroy submodules' '
 	mkdir dummy dest &&
 	git mv -k dummy sub dest &&
 	git status --porcelain >actual &&
-	grep "^R  sub -> dest/sub" actual &&
+	test_grep "^R  sub -> dest/sub" actual &&
 	git reset --hard &&
 	git checkout .
 '
diff --git a/t/t7002-mv-sparse-checkout.sh b/t/t7002-mv-sparse-checkout.sh
index 4d3f221224..9c0e82ba31 100755
--- a/t/t7002-mv-sparse-checkout.sh
+++ b/t/t7002-mv-sparse-checkout.sh
@@ -319,8 +319,8 @@ test_expect_success 'move clean path from in-cone to out-of-cone' '
 	test_path_is_missing sub/d &&
 	test_path_is_missing folder1/d &&
 	git ls-files -t >actual &&
-	! grep "^H sub/d\$" actual &&
-	grep "S folder1/d" actual
+	test_grep ! "^H sub/d\$" actual &&
+	test_grep "S folder1/d" actual
 '
 
 test_expect_success 'move clean path from in-cone to out-of-cone overwrite' '
@@ -346,8 +346,8 @@ test_expect_success 'move clean path from in-cone to out-of-cone overwrite' '
 	test_path_is_missing sub/file1 &&
 	test_path_is_missing folder1/file1 &&
 	git ls-files -t >actual &&
-	! grep "H sub/file1" actual &&
-	grep "S folder1/file1" actual &&
+	test_grep ! "H sub/file1" actual &&
+	test_grep "S folder1/file1" actual &&
 
 	# compare file content before move and after move
 	echo "sub/file1 overwrite" >expect &&
@@ -382,8 +382,8 @@ test_expect_success 'move clean path from in-cone to out-of-cone file overwrite'
 	test_path_is_missing sub/file1 &&
 	test_path_is_missing folder1/file1 &&
 	git ls-files -t >actual &&
-	! grep "H sub/file1" actual &&
-	grep "S folder1/file1" actual &&
+	test_grep ! "H sub/file1" actual &&
+	test_grep "S folder1/file1" actual &&
 
 	# compare file content before move and after move
 	echo "sub/file1 overwrite" >expect &&
@@ -421,9 +421,9 @@ test_expect_success 'move directory with one of the files overwrite' '
 	test_path_is_missing sub/dir/e &&
 	test_path_is_missing folder1/file1 &&
 	git ls-files -t >actual &&
-	! grep "H sub/dir/file1" actual &&
-	! grep "H sub/dir/e" actual &&
-	grep "S folder1/dir/file1" actual &&
+	test_grep ! "H sub/dir/file1" actual &&
+	test_grep ! "H sub/dir/e" actual &&
+	test_grep "S folder1/dir/file1" actual &&
 
 	# compare file content before move and after move
 	echo test >expect &&
@@ -452,8 +452,8 @@ test_expect_success 'move dirty path from in-cone to out-of-cone' '
 	test_path_is_missing sub/d &&
 	test_path_is_file folder1/d &&
 	git ls-files -t >actual &&
-	! grep "^H sub/d\$" actual &&
-	grep "H folder1/d" actual
+	test_grep ! "^H sub/d\$" actual &&
+	test_grep "H folder1/d" actual
 '
 
 test_expect_success 'move dir from in-cone to out-of-cone' '
@@ -473,8 +473,8 @@ test_expect_success 'move dir from in-cone to out-of-cone' '
 	test_path_is_missing sub/dir &&
 	test_path_is_missing folder1 &&
 	git ls-files -t >actual &&
-	! grep "H sub/dir/e" actual &&
-	grep "S folder1/dir/e" actual
+	test_grep ! "H sub/dir/e" actual &&
+	test_grep "S folder1/dir/e" actual
 '
 
 test_expect_success 'move partially-dirty dir from in-cone to out-of-cone' '
@@ -506,12 +506,12 @@ test_expect_success 'move partially-dirty dir from in-cone to out-of-cone' '
 	test_path_is_file folder1/dir/e2 &&
 	test_path_is_file folder1/dir/e3 &&
 	git ls-files -t >actual &&
-	! grep "H sub/dir/e" actual &&
-	! grep "H sub/dir/e2" actual &&
-	! grep "H sub/dir/e3" actual &&
-	grep "S folder1/dir/e" actual &&
-	grep "H folder1/dir/e2" actual &&
-	grep "H folder1/dir/e3" actual
+	test_grep ! "H sub/dir/e" actual &&
+	test_grep ! "H sub/dir/e2" actual &&
+	test_grep ! "H sub/dir/e3" actual &&
+	test_grep "S folder1/dir/e" actual &&
+	test_grep "H folder1/dir/e2" actual &&
+	test_grep "H folder1/dir/e3" actual
 '
 
 test_done
diff --git a/t/t7003-filter-branch.sh b/t/t7003-filter-branch.sh
index c475769858..86011e7b1f 100755
--- a/t/t7003-filter-branch.sh
+++ b/t/t7003-filter-branch.sh
@@ -49,7 +49,7 @@ test_expect_success 'result is really identical' '
 test_expect_success 'rewrite bare repository identically' '
 	(git config core.bare true && cd .git &&
 	 git filter-branch branch > filter-output 2>&1 &&
-	! grep fatal filter-output)
+	test_grep ! fatal filter-output)
 '
 git config core.bare false
 test_expect_success 'result is really identical' '
@@ -65,7 +65,7 @@ test_expect_success 'correct GIT_DIR while using -d' '
 	git filter-branch -d "$TRASHDIR/dfoo" \
 		--index-filter "cp \"$TRASHDIR\"/dfoo/backup-refs \"$TRASHDIR\"" \
 	) &&
-	grep drepo "$TRASHDIR/backup-refs"
+	test_grep drepo "$TRASHDIR/backup-refs"
 '
 
 test_expect_success 'tree-filter works with -d' '
@@ -503,7 +503,7 @@ test_expect_success 'rewrite repository including refs that point at non-commit
 	git tag -a -m "tag to a tree" treetag $new_tree &&
 	git reset --hard HEAD &&
 	git filter-branch -f -- --all >filter-output 2>&1 &&
-	! grep fatal filter-output
+	test_grep ! fatal filter-output
 '
 
 test_expect_success 'filter-branch handles ref deletion' '
@@ -512,7 +512,7 @@ test_expect_success 'filter-branch handles ref deletion' '
 	git tag empty &&
 	git branch to-delete &&
 	git filter-branch -f --prune-empty to-delete >out 2>&1 &&
-	grep "to-delete.*was deleted" out &&
+	test_grep "to-delete.*was deleted" out &&
 	test_must_fail git rev-parse --verify to-delete
 '
 
@@ -523,8 +523,8 @@ test_expect_success 'filter-branch handles ref rewrite' '
 	git filter-branch -f \
 		--index-filter "git rm --ignore-unmatch --cached to-drop.t" \
 		 rewrite >out 2>&1 &&
-	grep "rewrite.*was rewritten" out &&
-	! grep -i warning out &&
+	test_grep "rewrite.*was rewritten" out &&
+	test_grep ! -i warning out &&
 	git diff-tree empty rewrite
 '
 
@@ -532,8 +532,8 @@ test_expect_success 'filter-branch handles ancestor rewrite' '
 	test_commit to-exclude &&
 	git branch ancestor &&
 	git filter-branch -f ancestor -- :^to-exclude.t >out 2>&1 &&
-	grep "ancestor.*was rewritten" out &&
-	! grep -i warning out &&
+	test_grep "ancestor.*was rewritten" out &&
+	test_grep ! -i warning out &&
 	git diff-tree HEAD^ ancestor
 '
 
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index d918005dd9..2ad30040df 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -937,7 +937,7 @@ test_expect_success 'git tag --format with ahead-behind' '
 	test_cmp expect actual.focus &&
 
 	# Error reported for tags that point to non-commits.
-	grep "error: object [0-9a-f]* is a blob, not a commit" err
+	test_grep "error: object [0-9a-f]* is a blob, not a commit" err
 '
 
 # trying to verify annotated non-signed tags:
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 9717e825f0..75ca7a25da 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -45,8 +45,8 @@ test_expect_success TTY 'LESS and LV envvars are set for pagination' '
 
 		test_terminal git log
 	) &&
-	grep ^LESS= pager-env.out &&
-	grep ^LV= pager-env.out
+	test_grep ^LESS= pager-env.out &&
+	test_grep ^LV= pager-env.out
 '
 
 test_expect_success !MINGW,TTY 'LESS and LV envvars set by git-sh-setup' '
@@ -58,8 +58,8 @@ test_expect_success !MINGW,TTY 'LESS and LV envvars set by git-sh-setup' '
 		export PATH &&
 		test_terminal sh -c ". git-sh-setup && git_pager"
 	) &&
-	grep ^LESS= pager-env.out &&
-	grep ^LV= pager-env.out
+	test_grep ^LESS= pager-env.out &&
+	test_grep ^LV= pager-env.out
 '
 
 test_expect_success TTY 'some commands do not use a pager' '
@@ -685,7 +685,7 @@ test_expect_success TTY 'git returns SIGPIPE on early pager exit' '
 
 	grep child_exit trace.normal >child-exits &&
 	test_line_count = 1 child-exits &&
-	grep " code:0 " child-exits &&
+	test_grep " code:0 " child-exits &&
 	test_path_is_file pager-used
 '
 
@@ -706,7 +706,7 @@ test_expect_success TTY 'git returns SIGPIPE on early pager non-zero exit' '
 
 	grep child_exit trace.normal >child-exits &&
 	test_line_count = 1 child-exits &&
-	grep " code:1 " child-exits &&
+	test_grep " code:1 " child-exits &&
 	test_path_is_file pager-used
 '
 
@@ -721,7 +721,7 @@ test_expect_success TTY 'git discards pager non-zero exit without SIGPIPE' '
 
 	grep child_exit trace.normal >child-exits &&
 	test_line_count = 1 child-exits &&
-	grep " code:1 " child-exits &&
+	test_grep " code:1 " child-exits &&
 	test_path_is_file pager-used
 '
 
@@ -749,7 +749,7 @@ test_expect_success TTY 'git returns SIGPIPE on propagated signals from pager' '
 
 	grep child_exit trace.normal >child-exits &&
 	test_line_count = 1 child-exits &&
-	grep " code:143 " child-exits &&
+	test_grep " code:143 " child-exits &&
 	test_path_is_file pager-used
 '
 
diff --git a/t/t7012-skip-worktree-writing.sh b/t/t7012-skip-worktree-writing.sh
index cd5c20fe51..f9fee199e2 100755
--- a/t/t7012-skip-worktree-writing.sh
+++ b/t/t7012-skip-worktree-writing.sh
@@ -30,7 +30,7 @@ test_expect_success 'read-tree updates worktree, dirty case' '
 	git update-index --skip-worktree init.t &&
 	echo dirty >> init.t &&
 	test_must_fail git read-tree -m -u HEAD^ &&
-	grep -q dirty init.t &&
+	test_grep dirty init.t &&
 	test "$(git ls-files -t init.t)" = "S init.t" &&
 	git update-index --no-skip-worktree init.t
 '
@@ -48,7 +48,7 @@ test_expect_success 'read-tree removes worktree, dirty case' '
 	git update-index --skip-worktree added &&
 	echo dirty >> added &&
 	test_must_fail git read-tree -m -u HEAD^ &&
-	grep -q dirty added &&
+	test_grep dirty added &&
 	test "$(git ls-files -t added)" = "S added" &&
 	git update-index --no-skip-worktree added
 '
@@ -173,7 +173,7 @@ test_expect_success 'stash restore in sparse checkout' '
 		echo in the way >modified &&
 		test_must_fail git stash apply 2>error&&
 
-		grep "changes.*would be overwritten by merge" error &&
+		test_grep "changes.*would be overwritten by merge" error &&
 
 		echo in the way >expect &&
 		test_cmp expect modified &&
diff --git a/t/t7030-verify-tag.sh b/t/t7030-verify-tag.sh
index 2c147072c1..b35f8ed1c0 100755
--- a/t/t7030-verify-tag.sh
+++ b/t/t7030-verify-tag.sh
@@ -63,8 +63,8 @@ test_expect_success GPG 'verify and show signatures' '
 		for tag in initial second merge fourth-signed sixth-signed seventh-signed
 		do
 			git verify-tag $tag 2>actual &&
-			grep "Good signature from" actual &&
-			! grep "BAD signature from" actual &&
+			test_grep "Good signature from" actual &&
+			test_grep ! "BAD signature from" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -72,8 +72,8 @@ test_expect_success GPG 'verify and show signatures' '
 		for tag in fourth-unsigned fifth-unsigned sixth-unsigned
 		do
 			test_must_fail git verify-tag $tag 2>actual &&
-			! grep "Good signature from" actual &&
-			! grep "BAD signature from" actual &&
+			test_grep ! "Good signature from" actual &&
+			test_grep ! "BAD signature from" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -81,9 +81,9 @@ test_expect_success GPG 'verify and show signatures' '
 		for tag in eighth-signed-alt
 		do
 			git verify-tag $tag 2>actual &&
-			grep "Good signature from" actual &&
-			! grep "BAD signature from" actual &&
-			grep "not certified" actual &&
+			test_grep "Good signature from" actual &&
+			test_grep ! "BAD signature from" actual &&
+			test_grep "not certified" actual &&
 			echo $tag OK || exit 1
 		done
 	)
@@ -91,32 +91,32 @@ test_expect_success GPG 'verify and show signatures' '
 
 test_expect_success GPGSM 'verify and show signatures x509' '
 	git verify-tag ninth-signed-x509 2>actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual &&
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual &&
 	echo ninth-signed-x509 OK
 '
 
 test_expect_success GPGSM 'verify and show signatures x509 with low minTrustLevel' '
 	test_config gpg.minTrustLevel undefined &&
 	git verify-tag ninth-signed-x509 2>actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual &&
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual &&
 	echo ninth-signed-x509 OK
 '
 
 test_expect_success GPGSM 'verify and show signatures x509 with matching minTrustLevel' '
 	test_config gpg.minTrustLevel fully &&
 	git verify-tag ninth-signed-x509 2>actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual &&
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual &&
 	echo ninth-signed-x509 OK
 '
 
 test_expect_success GPGSM 'verify and show signatures x509 with high minTrustLevel' '
 	test_config gpg.minTrustLevel ultimate &&
 	test_must_fail git verify-tag ninth-signed-x509 2>actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual &&
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual &&
 	echo ninth-signed-x509 OK
 '
 
@@ -125,8 +125,8 @@ test_expect_success GPG 'detect fudged signature' '
 	sed -e "/^tag / s/seventh/7th-forged/" raw >forged1 &&
 	git hash-object -w -t tag forged1 >forged1.tag &&
 	test_must_fail git verify-tag $(cat forged1.tag) 2>actual1 &&
-	grep "BAD signature from" actual1 &&
-	! grep "Good signature from" actual1
+	test_grep "BAD signature from" actual1 &&
+	test_grep ! "Good signature from" actual1
 '
 
 test_expect_success GPG 'verify signatures with --raw' '
@@ -134,8 +134,8 @@ test_expect_success GPG 'verify signatures with --raw' '
 		for tag in initial second merge fourth-signed sixth-signed seventh-signed
 		do
 			git verify-tag --raw $tag 2>actual &&
-			grep "GOODSIG" actual &&
-			! grep "BADSIG" actual &&
+			test_grep "GOODSIG" actual &&
+			test_grep ! "BADSIG" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -143,8 +143,8 @@ test_expect_success GPG 'verify signatures with --raw' '
 		for tag in fourth-unsigned fifth-unsigned sixth-unsigned
 		do
 			test_must_fail git verify-tag --raw $tag 2>actual &&
-			! grep "GOODSIG" actual &&
-			! grep "BADSIG" actual &&
+			test_grep ! "GOODSIG" actual &&
+			test_grep ! "BADSIG" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -152,9 +152,9 @@ test_expect_success GPG 'verify signatures with --raw' '
 		for tag in eighth-signed-alt
 		do
 			git verify-tag --raw $tag 2>actual &&
-			grep "GOODSIG" actual &&
-			! grep "BADSIG" actual &&
-			grep "TRUST_UNDEFINED" actual &&
+			test_grep "GOODSIG" actual &&
+			test_grep ! "BADSIG" actual &&
+			test_grep "TRUST_UNDEFINED" actual &&
 			echo $tag OK || exit 1
 		done
 	)
@@ -162,8 +162,8 @@ test_expect_success GPG 'verify signatures with --raw' '
 
 test_expect_success GPGSM 'verify signatures with --raw x509' '
 	git verify-tag --raw ninth-signed-x509 2>actual &&
-	grep "GOODSIG" actual &&
-	! grep "BADSIG" actual &&
+	test_grep "GOODSIG" actual &&
+	test_grep ! "BADSIG" actual &&
 	echo ninth-signed-x509 OK
 '
 
diff --git a/t/t7031-verify-tag-signed-ssh.sh b/t/t7031-verify-tag-signed-ssh.sh
index 80359d48f7..3000beb7c0 100755
--- a/t/t7031-verify-tag-signed-ssh.sh
+++ b/t/t7031-verify-tag-signed-ssh.sh
@@ -71,8 +71,8 @@ test_expect_success GPGSSH 'verify and show ssh signatures' '
 		for tag in initial second merge fourth-signed sixth-signed seventh-signed
 		do
 			git verify-tag $tag 2>actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -80,8 +80,8 @@ test_expect_success GPGSSH 'verify and show ssh signatures' '
 		for tag in fourth-unsigned fifth-unsigned sixth-unsigned
 		do
 			test_must_fail git verify-tag $tag 2>actual &&
-			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -89,9 +89,9 @@ test_expect_success GPGSSH 'verify and show ssh signatures' '
 		for tag in eighth-signed-alt
 		do
 			test_must_fail git verify-tag $tag 2>actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
-			grep "${GPGSSH_KEY_NOT_TRUSTED}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_KEY_NOT_TRUSTED}" actual &&
 			echo $tag OK || exit 1
 		done
 	)
@@ -100,26 +100,26 @@ test_expect_success GPGSSH 'verify and show ssh signatures' '
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag exits failure on expired signature key' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_must_fail git verify-tag expired-signed 2>actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag exits failure on not yet valid signature key' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_must_fail git verify-tag notyetvalid-signed 2>actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag succeeds with tag date and key validity matching' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git verify-tag timeboxedvalid-signed 2>actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag fails with tag date outside of key validity' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_must_fail git verify-tag timeboxedinvalid-signed 2>actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH 'detect fudged ssh signature' '
@@ -128,9 +128,9 @@ test_expect_success GPGSSH 'detect fudged ssh signature' '
 	sed -e "/^tag / s/seventh/7th-forged/" raw >forged1 &&
 	git hash-object -w -t tag forged1 >forged1.tag &&
 	test_must_fail git verify-tag $(cat forged1.tag) 2>actual1 &&
-	grep "${GPGSSH_BAD_SIGNATURE}" actual1 &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual1 &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual1
+	test_grep "${GPGSSH_BAD_SIGNATURE}" actual1 &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual1 &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual1
 '
 
 test_expect_success GPGSSH 'verify ssh signatures with --raw' '
@@ -139,8 +139,8 @@ test_expect_success GPGSSH 'verify ssh signatures with --raw' '
 		for tag in initial second merge fourth-signed sixth-signed seventh-signed
 		do
 			git verify-tag --raw $tag 2>actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -148,8 +148,8 @@ test_expect_success GPGSSH 'verify ssh signatures with --raw' '
 		for tag in fourth-unsigned fifth-unsigned sixth-unsigned
 		do
 			test_must_fail git verify-tag --raw $tag 2>actual &&
-			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $tag OK || exit 1
 		done
 	) &&
@@ -157,8 +157,8 @@ test_expect_success GPGSSH 'verify ssh signatures with --raw' '
 		for tag in eighth-signed-alt
 		do
 			test_must_fail git verify-tag --raw $tag 2>actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $tag OK || exit 1
 		done
 	)
@@ -167,8 +167,8 @@ test_expect_success GPGSSH 'verify ssh signatures with --raw' '
 test_expect_success GPGSSH 'verify signatures with --raw ssh' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git verify-tag --raw sixth-signed 2>actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 	echo sixth-signed OK
 '
 
diff --git a/t/t7102-reset.sh b/t/t7102-reset.sh
index 0503a64d3f..298272cb13 100755
--- a/t/t7102-reset.sh
+++ b/t/t7102-reset.sh
@@ -87,7 +87,7 @@ do
 	test_expect_success "no 'git reset --no-$opt'" '
 		test_when_finished "rm -f err" &&
 		test_must_fail git reset --no-$opt 2>err &&
-		grep "error: unknown option .no-$opt." err
+		test_grep "error: unknown option .no-$opt." err
 	'
 done
 
diff --git a/t/t7110-reset-merge.sh b/t/t7110-reset-merge.sh
index 9a335071af..a241ecfc0b 100755
--- a/t/t7110-reset-merge.sh
+++ b/t/t7110-reset-merge.sh
@@ -29,16 +29,16 @@ test_expect_success setup '
 # file2:     C       D     D    D     --merge  C       D     D
 test_expect_success 'reset --merge is ok with changes in file it does not touch' '
 	git reset --merge HEAD^ &&
-	! grep 4 file1 &&
-	grep 4 file2 &&
+	test_grep ! 4 file1 &&
+	test_grep 4 file2 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse initial)" &&
 	test -z "$(git diff --cached)"
 '
 
 test_expect_success 'reset --merge is ok when switching back' '
 	git reset --merge second &&
-	grep 4 file1 &&
-	grep 4 file2 &&
+	test_grep 4 file1 &&
+	test_grep 4 file2 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse second)" &&
 	test -z "$(git diff --cached)"
 '
@@ -53,16 +53,16 @@ test_expect_success 'reset --keep is ok with changes in file it does not touch'
 	git reset --hard second &&
 	cat file1 >file2 &&
 	git reset --keep HEAD^ &&
-	! grep 4 file1 &&
-	grep 4 file2 &&
+	test_grep ! 4 file1 &&
+	test_grep 4 file2 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse initial)" &&
 	test -z "$(git diff --cached)"
 '
 
 test_expect_success 'reset --keep is ok when switching back' '
 	git reset --keep second &&
-	grep 4 file1 &&
-	grep 4 file2 &&
+	test_grep 4 file1 &&
+	test_grep 4 file2 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse second)" &&
 	test -z "$(git diff --cached)"
 '
@@ -79,9 +79,9 @@ test_expect_success 'reset --merge discards changes added to index (1)' '
 	echo "line 5" >> file1 &&
 	git add file1 &&
 	git reset --merge HEAD^ &&
-	! grep 4 file1 &&
-	! grep 5 file1 &&
-	grep 4 file2 &&
+	test_grep ! 4 file1 &&
+	test_grep ! 5 file1 &&
+	test_grep 4 file2 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse initial)" &&
 	test -z "$(git diff --cached)"
 '
@@ -91,9 +91,9 @@ test_expect_success 'reset --merge is ok again when switching back (1)' '
 	echo "line 5" >> file2 &&
 	git add file2 &&
 	git reset --merge second &&
-	! grep 4 file2 &&
-	! grep 5 file1 &&
-	grep 4 file1 &&
+	test_grep ! 4 file2 &&
+	test_grep ! 5 file1 &&
+	test_grep 4 file1 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse second)" &&
 	test -z "$(git diff --cached)"
 '
@@ -121,7 +121,7 @@ test_expect_success 'reset --merge discards changes added to index (2)' '
 	echo "line 4" >> file2 &&
 	git add file2 &&
 	git reset --merge HEAD^ &&
-	! grep 4 file2 &&
+	test_grep ! 4 file2 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse initial)" &&
 	test -z "$(git diff)" &&
 	test -z "$(git diff --cached)"
@@ -130,8 +130,8 @@ test_expect_success 'reset --merge discards changes added to index (2)' '
 test_expect_success 'reset --merge is ok again when switching back (2)' '
 	git reset --hard initial &&
 	git reset --merge second &&
-	! grep 4 file2 &&
-	grep 4 file1 &&
+	test_grep ! 4 file2 &&
+	test_grep 4 file1 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse second)" &&
 	test -z "$(git diff --cached)"
 '
@@ -147,15 +147,15 @@ test_expect_success 'reset --keep keeps changes it does not touch' '
 	echo "line 4" >> file2 &&
 	git add file2 &&
 	git reset --keep HEAD^ &&
-	grep 4 file2 &&
+	test_grep 4 file2 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse initial)" &&
 	test -z "$(git diff --cached)"
 '
 
 test_expect_success 'reset --keep keeps changes when switching back' '
 	git reset --keep second &&
-	grep 4 file2 &&
-	grep 4 file1 &&
+	test_grep 4 file2 &&
+	test_grep 4 file1 &&
 	test "$(git rev-parse HEAD)" = "$(git rev-parse second)" &&
 	test -z "$(git diff --cached)"
 '
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 7613b1d2a4..0ddd1ad7aa 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -318,7 +318,7 @@ test_expect_success 'checkout to detach HEAD' '
 	git checkout -f renamer &&
 	git clean -f &&
 	git checkout renamer^ 2>messages &&
-	grep "HEAD is now at $rev" messages &&
+	test_grep "HEAD is now at $rev" messages &&
 	test_line_count -gt 1 messages &&
 	H=$(git rev-parse --verify HEAD) &&
 	M=$(git show-ref -s --verify refs/heads/main) &&
@@ -794,7 +794,7 @@ test_expect_success 'switch out of non-branch' '
 	git checkout main^0 &&
 	echo modified >one &&
 	test_must_fail git checkout renamer 2>error.log &&
-	! grep "^Previous HEAD" error.log
+	test_grep ! "^Previous HEAD" error.log
 '
 
 (
@@ -844,7 +844,7 @@ test_expect_success 'custom merge driver with checkout -m' '
 	(
 		for t in filfre-common left right
 		do
-			grep $t arm || exit 1
+			test_grep $t arm || exit 1
 		done
 	) &&
 
diff --git a/t/t7300-clean.sh b/t/t7300-clean.sh
index 00d4070156..13ad3eec77 100755
--- a/t/t7300-clean.sh
+++ b/t/t7300-clean.sh
@@ -793,7 +793,7 @@ test_expect_success 'traverse into directories that may have ignored entries' '
 
 		git clean -fX modules/foobar >../output &&
 
-		grep Removing ../output &&
+		test_grep Removing ../output &&
 
 		test_path_is_missing modules/foobar/src/generated/code.c &&
 		test_path_is_file modules/foobar/Makefile
diff --git a/t/t7301-clean-interactive.sh b/t/t7301-clean-interactive.sh
index f743e5b8f4..de59ba3724 100755
--- a/t/t7301-clean-interactive.sh
+++ b/t/t7301-clean-interactive.sh
@@ -479,7 +479,7 @@ test_expect_success TTY 'git clean -i paints the header in HEADER color' '
 	test_decode_color |
 	head -n 1 >header &&
 	# not i18ngrep
-	grep "^<BOLD>" header
+	test_grep "^<BOLD>" header
 '
 
 test_done
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index 65fcfae93a..eefdecb0bd 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -20,13 +20,13 @@ test_expect_success 'setup - enable local submodules' '
 
 test_expect_success 'submodule usage: -h' '
 	git submodule -h >out 2>err &&
-	grep "^usage: git submodule" out &&
+	test_grep "^usage: git submodule" out &&
 	test_must_be_empty err
 '
 
 test_expect_success 'submodule usage: --recursive' '
 	test_expect_code 1 git submodule --recursive >out 2>err &&
-	grep "^usage: git submodule" err &&
+	test_grep "^usage: git submodule" err &&
 	test_must_be_empty out
 '
 
@@ -214,14 +214,14 @@ test_expect_success 'setup parent and one repository' '
 test_expect_success 'redirected submodule add does not show progress' '
 	git -C addtest submodule add "file://$submodurl/parent" submod-redirected \
 		2>err &&
-	! grep % err &&
+	test_grep ! % err &&
 	test_grep ! "Checking connectivity" err
 '
 
 test_expect_success 'redirected submodule add --progress does show progress' '
 	git -C addtest submodule add --progress "file://$submodurl/parent" \
 		submod-redirected-progress 2>err && \
-	grep % err
+	test_grep % err
 '
 
 test_expect_success 'submodule add to .gitignored path fails' '
@@ -506,7 +506,7 @@ test_expect_success 'setup - fetch commit name from submodule' '
 
 test_expect_success 'status should initially be "missing"' '
 	git submodule status >lines &&
-	grep "^-$rev1" lines
+	test_grep "^-$rev1" lines
 '
 
 test_expect_success 'init should register submodule url in .git/config' '
@@ -524,7 +524,7 @@ test_expect_success 'status should still be "missing" after initializing' '
 	mkdir init &&
 	git submodule status >lines &&
 	rm -fr init &&
-	grep "^-$rev1" lines
+	test_grep "^-$rev1" lines
 '
 
 test_failure_with_unknown_submodule () {
@@ -584,7 +584,7 @@ test_expect_success 'update should work when path is an empty dir' '
 
 test_expect_success 'status should be "up-to-date" after update' '
 	git submodule status >list &&
-	grep "^ $rev1" list
+	test_grep "^ $rev1" list
 '
 
 test_expect_success 'status "up-to-date" from subdirectory' '
@@ -593,8 +593,8 @@ test_expect_success 'status "up-to-date" from subdirectory' '
 		cd sub &&
 		git submodule status >../list
 	) &&
-	grep "^ $rev1" list &&
-	grep "\\.\\./init" list
+	test_grep "^ $rev1" list &&
+	test_grep "\\.\\./init" list
 '
 
 test_expect_success 'status "up-to-date" from subdirectory with path' '
@@ -603,8 +603,8 @@ test_expect_success 'status "up-to-date" from subdirectory with path' '
 		cd sub &&
 		git submodule status ../init >../list
 	) &&
-	grep "^ $rev1" list &&
-	grep "\\.\\./init" list
+	test_grep "^ $rev1" list &&
+	test_grep "\\.\\./init" list
 '
 
 test_expect_success 'status should be "modified" after submodule commit' '
@@ -619,7 +619,7 @@ test_expect_success 'status should be "modified" after submodule commit' '
 	test -n "$rev2" &&
 	git submodule status >list &&
 
-	grep "^+$rev2" list
+	test_grep "^+$rev2" list
 '
 
 test_expect_success '"submodule --cached" command forms should be identical' '
@@ -634,12 +634,12 @@ test_expect_success '"submodule --cached" command forms should be identical' '
 
 test_expect_success 'the --cached sha1 should be rev1' '
 	git submodule --cached status >list &&
-	grep "^+$rev1" list
+	test_grep "^+$rev1" list
 '
 
 test_expect_success 'git diff should report the SHA1 of the new submodule commit' '
 	git diff >diff &&
-	grep "^+Subproject commit $rev2" diff
+	test_grep "^+Subproject commit $rev2" diff
 '
 
 test_expect_success 'update should checkout rev1' '
@@ -654,7 +654,7 @@ test_expect_success 'update should checkout rev1' '
 
 test_expect_success 'status should be "up-to-date" after update' '
 	git submodule status >list &&
-	grep "^ $rev1" list
+	test_grep "^ $rev1" list
 '
 
 test_expect_success 'checkout superproject with subproject already present' '
@@ -1407,7 +1407,7 @@ test_expect_success 'update submodules without url set in .gitconfig' '
 	done &&
 
 	test_must_fail git -C multisuper_clone submodule update 2>err &&
-	grep "cannot clone submodule .sub[0-3]. without a URL" err
+	test_grep "cannot clone submodule .sub[0-3]. without a URL" err
 '
 
 test_expect_success 'clone --recurse-submodules with a pathspec works' '
diff --git a/t/t7402-submodule-rebase.sh b/t/t7402-submodule-rebase.sh
index 06cee3432f..872eb2d3ab 100755
--- a/t/t7402-submodule-rebase.sh
+++ b/t/t7402-submodule-rebase.sh
@@ -125,7 +125,7 @@ test_expect_success 'rebasing submodule that should conflict' '
 	) >expect &&
 	test_cmp expect actual &&
 	sub_expect="go to submodule (submodule), and either merge commit $(git -C submodule rev-parse --short HEAD^0)" &&
-	grep "$sub_expect" actual_output
+	test_grep "$sub_expect" actual_output
 '
 
 test_done
diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index 6abb00876a..9554720152 100755
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh
@@ -627,10 +627,10 @@ test_expect_success 'submodule update - update=none in .git/config' '
 	  compare_head
 	 ) &&
 	 git diff --name-only >out &&
-	 grep ^submodule$ out &&
+	 test_grep ^submodule$ out &&
 	 git submodule update &&
 	 git diff --name-only >out &&
-	 grep ^submodule$ out &&
+	 test_grep ^submodule$ out &&
 	 (cd submodule &&
 	  compare_head
 	 ) &&
@@ -647,10 +647,10 @@ test_expect_success 'submodule update - update=none in .git/config but --checkou
 	  compare_head
 	 ) &&
 	 git diff --name-only >out &&
-	 grep ^submodule$ out &&
+	 test_grep ^submodule$ out &&
 	 git submodule update --checkout &&
 	 git diff --name-only >out &&
-	 ! grep ^submodule$ out &&
+	 test_grep ! ^submodule$ out &&
 	 (cd submodule &&
 	  ! compare_head
 	 ) &&
@@ -679,10 +679,10 @@ test_expect_success 'submodule update with pathspec warns against uninitialized
 		git submodule init submodule &&
 
 		git submodule update submodule 2>err &&
-		! grep "Submodule path .* not initialized" err &&
+		test_grep ! "Submodule path .* not initialized" err &&
 
 		git submodule update rebasing 2>err &&
-		grep "Submodule path .rebasing. not initialized" err &&
+		test_grep "Submodule path .rebasing. not initialized" err &&
 
 		test_path_exists submodule/.git &&
 		test_path_is_missing rebasing/.git
@@ -699,7 +699,7 @@ test_expect_success 'submodule update without pathspec updates only initialized
 		git submodule update 2>err &&
 		test_path_exists submodule/.git &&
 		test_path_is_missing rebasing/.git &&
-		! grep "Submodule path .* not initialized" err
+		test_grep ! "Submodule path .* not initialized" err
 	)
 
 '
@@ -1046,12 +1046,12 @@ test_expect_success 'submodule update --recursive drops module name before recur
 test_expect_success 'submodule update can be run in parallel' '
 	(cd super2 &&
 	 GIT_TRACE=$(pwd)/trace.out git submodule update --jobs 7 &&
-	 grep "7 tasks" trace.out &&
+	 test_grep "7 tasks" trace.out &&
 	 git config submodule.fetchJobs 8 &&
 	 GIT_TRACE=$(pwd)/trace.out git submodule update &&
-	 grep "8 tasks" trace.out &&
+	 test_grep "8 tasks" trace.out &&
 	 GIT_TRACE=$(pwd)/trace.out git submodule update --jobs 9 &&
-	 grep "9 tasks" trace.out
+	 test_grep "9 tasks" trace.out
 	)
 '
 
@@ -1066,14 +1066,14 @@ test_expect_success 'submodule update honors fetch jobs config from .gitmodules'
 test_expect_success 'git clone passes the parallel jobs config on to submodules' '
 	test_when_finished "rm -rf super4" &&
 	GIT_TRACE=$(pwd)/trace.out git clone --recurse-submodules --jobs 7 . super4 &&
-	grep "7 tasks" trace.out &&
+	test_grep "7 tasks" trace.out &&
 	rm -rf super4 &&
 	git config --global submodule.fetchJobs 8 &&
 	GIT_TRACE=$(pwd)/trace.out git clone --recurse-submodules . super4 &&
-	grep "8 tasks" trace.out &&
+	test_grep "8 tasks" trace.out &&
 	rm -rf super4 &&
 	GIT_TRACE=$(pwd)/trace.out git clone --recurse-submodules --jobs 9 . super4 &&
-	grep "9 tasks" trace.out &&
+	test_grep "9 tasks" trace.out &&
 	rm -rf super4
 '
 
diff --git a/t/t7416-submodule-dash-url.sh b/t/t7416-submodule-dash-url.sh
index 3d944a00e0..9f4af88ed5 100755
--- a/t/t7416-submodule-dash-url.sh
+++ b/t/t7416-submodule-dash-url.sh
@@ -49,7 +49,7 @@ test_expect_success 'fsck rejects unprotected dash' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'trailing backslash is handled correctly' '
@@ -79,7 +79,7 @@ test_expect_success 'fsck rejects missing URL scheme' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck rejects relative URL resolving to missing scheme' '
@@ -95,7 +95,7 @@ test_expect_success 'fsck rejects relative URL resolving to missing scheme' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck rejects empty URL scheme' '
@@ -111,7 +111,7 @@ test_expect_success 'fsck rejects empty URL scheme' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck rejects relative URL resolving to empty scheme' '
@@ -127,7 +127,7 @@ test_expect_success 'fsck rejects relative URL resolving to empty scheme' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck rejects empty hostname' '
@@ -143,7 +143,7 @@ test_expect_success 'fsck rejects empty hostname' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck rejects relative url that produced empty hostname' '
@@ -159,7 +159,7 @@ test_expect_success 'fsck rejects relative url that produced empty hostname' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck permits embedded newline with unrecognized scheme' '
@@ -189,7 +189,7 @@ test_expect_success 'fsck rejects embedded newline in url' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck rejects embedded newline in relative url' '
@@ -204,7 +204,7 @@ test_expect_success 'fsck rejects embedded newline in relative url' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_expect_success 'fsck rejects embedded newline in git url' '
@@ -219,7 +219,7 @@ test_expect_success 'fsck rejects embedded newline in git url' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesUrl err
+	test_grep gitmodulesUrl err
 '
 
 test_done
diff --git a/t/t7417-submodule-path-url.sh b/t/t7417-submodule-path-url.sh
index 5e3051da8b..7a6f61585b 100755
--- a/t/t7417-submodule-path-url.sh
+++ b/t/t7417-submodule-path-url.sh
@@ -29,7 +29,7 @@ test_expect_success 'fsck rejects unprotected dash' '
 	git init --bare dst &&
 	git -C dst config transfer.fsckObjects true &&
 	test_must_fail git push dst HEAD 2>err &&
-	grep gitmodulesPath err
+	test_grep gitmodulesPath err
 '
 
 test_expect_success MINGW 'submodule paths disallows trailing spaces' '
diff --git a/t/t7450-bad-git-dotfiles.sh b/t/t7450-bad-git-dotfiles.sh
index 8cc86522b2..2a4d7f2d47 100755
--- a/t/t7450-bad-git-dotfiles.sh
+++ b/t/t7450-bad-git-dotfiles.sh
@@ -109,7 +109,7 @@ test_expect_success 'add other submodule' '
 
 test_expect_success 'clone evil superproject' '
 	git clone --recurse-submodules . victim >output 2>&1 &&
-	! grep "RUNNING POST CHECKOUT" output
+	test_grep ! "RUNNING POST CHECKOUT" output
 '
 
 test_expect_success 'fsck detects evil superproject' '
@@ -167,7 +167,7 @@ test_expect_success 'index-pack --strict works for non-repo pack' '
 	test_must_fail git -C dst.git index-pack --strict odd.pack 2>output &&
 	# Make sure we fail due to bad gitmodules content, not because we
 	# could not read the blob in the first place.
-	grep gitmodulesName output
+	test_grep gitmodulesName output
 '
 
 check_dotx_symlink () {
@@ -216,7 +216,7 @@ check_dotx_symlink () {
 			# Check not only that we fail, but that it is due to the
 			# symlink detector
 			$fsck_must_fail git fsck 2>output &&
-			grep "$fsck_prefix.*tree $tree: ${name}Symlink" output
+			test_grep "$fsck_prefix.*tree $tree: ${name}Symlink" output
 		)
 	'
 
@@ -228,7 +228,7 @@ check_dotx_symlink () {
 				    -c core.protectntfs \
 				    -c core.protecthfs \
 				    read-tree $tree 2>err &&
-			grep "invalid path.*$name" err &&
+			test_grep "invalid path.*$name" err &&
 			git -C $dir ls-files -s >out &&
 			test_must_be_empty out
 		'
@@ -317,7 +317,7 @@ test_expect_success WINDOWS 'prevent git~1 squatting on Windows' '
 		test_must_fail git -c core.protectNTFS=false \
 			clone --recurse-submodules squatting squatting-clone 2>err &&
 		test_grep -e "directory not empty" -e "not an empty directory" err &&
-		! grep gitdir squatting-clone/d/a/git~2
+		! grep gitdir squatting-clone/d/a/git~2 # lint-ok: file may not exist
 	fi
 '
 
@@ -350,7 +350,7 @@ test_expect_success 'git dirs of sibling submodules must not be nested' '
 test_expect_success 'submodule git dir nesting detection must work with parallel cloning' '
 	test_must_fail git clone --recurse-submodules --jobs=2 nested clone_parallel 2>err &&
 	cat err &&
-	grep -E "(already exists|is inside git dir|not a git repository)" err &&
+	test_grep -E "(already exists|is inside git dir|not a git repository)" err &&
 	{
 		test_path_is_missing .git/modules/hippo/HEAD ||
 		test_path_is_missing .git/modules/hippo/hooks/HEAD
@@ -370,7 +370,7 @@ test_expect_success 'checkout -f --recurse-submodules must not use a nested gitd
 	) &&
 	test_must_fail git -C nested_checkout checkout -f --recurse-submodules HEAD 2>err &&
 	cat err &&
-	grep "is inside git dir" err &&
+	test_grep "is inside git dir" err &&
 	test_path_is_missing nested_checkout/thing2/.git
 '
 
diff --git a/t/t7501-commit-basic-functionality.sh b/t/t7501-commit-basic-functionality.sh
index a37509f004..88b4468319 100755
--- a/t/t7501-commit-basic-functionality.sh
+++ b/t/t7501-commit-basic-functionality.sh
@@ -342,12 +342,12 @@ test_expect_success 'overriding author from command line' '
 	echo gak >file &&
 	git commit -m author \
 		--author "Rubber Duck <rduck@convoy.org>" -a >output 2>&1 &&
-	grep Rubber.Duck output
+	test_grep Rubber.Duck output
 '
 
 test_expect_success 'interactive add' '
 	echo 7 | test_must_fail git commit --interactive >out &&
-	grep "What now" out
+	test_grep "What now" out
 '
 
 test_expect_success "commit --interactive doesn't change index if editor aborts" '
@@ -376,13 +376,13 @@ test_expect_success 'editor not invoked if -F is given' '
 
 	EDITOR=./editor git commit -a -F msg &&
 	git show -s --pretty=format:%s >subject &&
-	grep -q good subject &&
+	test_grep good subject &&
 
 	echo quack >file &&
 	echo Another good message. |
 	EDITOR=./editor git commit -a -F - &&
 	git show -s --pretty=format:%s >subject &&
-	grep -q good subject
+	test_grep good subject
 '
 
 test_expect_success 'partial commit that involves removal (1)' '
@@ -471,7 +471,7 @@ test_expect_success 'amend does not add signoff if it already exists' '
 
 test_expect_success 'commit mentions forced date in output' '
 	git commit --amend --date=2010-01-02T03:04:05 >output &&
-	grep "Date: *Sat Jan 2 03:04:05 2010" output
+	test_grep "Date: *Sat Jan 2 03:04:05 2010" output
 '
 
 test_expect_success 'commit complains about completely bogus dates' '
@@ -662,7 +662,7 @@ test_expect_success 'git commit <file> with dirty index' '
 	git show --stat >stat &&
 	grep elif stat &&
 	git diff --cached >diff &&
-	grep chz diff
+	test_grep chz diff
 '
 
 test_expect_success 'same tree (single parent)' '
@@ -676,7 +676,7 @@ test_expect_success 'same tree (single parent) --allow-empty' '
 
 	git commit --allow-empty -m "forced empty" &&
 	git cat-file commit HEAD >commit &&
-	grep forced commit
+	test_grep forced commit
 
 '
 
diff --git a/t/t7502-commit-porcelain.sh b/t/t7502-commit-porcelain.sh
index 05f6da4ad9..62e3970e3f 100755
--- a/t/t7502-commit-porcelain.sh
+++ b/t/t7502-commit-porcelain.sh
@@ -529,7 +529,7 @@ test_expect_success 'verbose respects diff config' '
 
 	test_config diff.noprefix true &&
 	git status -v >actual &&
-	grep "diff --git negative negative" actual
+	test_grep "diff --git negative negative" actual
 '
 
 mesg_with_comment_and_newlines='
diff --git a/t/t7507-commit-verbose.sh b/t/t7507-commit-verbose.sh
index acdb6b1455..8e9d8ff3ae 100755
--- a/t/t7507-commit-verbose.sh
+++ b/t/t7507-commit-verbose.sh
@@ -106,13 +106,13 @@ test_expect_success 'verbose diff is stripped with multi-byte comment char' '
 		export GIT_EDITOR &&
 		test_must_fail git -c core.commentchar="foo>" commit -a -v >out 2>err
 	) &&
-	grep "^foo> " out &&
+	test_grep "^foo> " out &&
 	test_grep "Aborting commit due to empty commit message." err
 '
 
 test_expect_success 'status does not verbose without --verbose' '
 	git status >actual &&
-	! grep "^diff --git" actual
+	test_grep ! "^diff --git" actual
 '
 
 test_expect_success 'setup -v -v' '
@@ -163,7 +163,7 @@ done
 
 test_expect_success "status ignores commit.verbose=true" '
 	git -c commit.verbose=true status >actual &&
-	! grep "^diff --git" actual
+	test_grep ! "^diff --git" actual
 '
 
 test_done
diff --git a/t/t7508-status.sh b/t/t7508-status.sh
index c2057bc94c..c37ffbe444 100755
--- a/t/t7508-status.sh
+++ b/t/t7508-status.sh
@@ -863,7 +863,7 @@ test_expect_success 'status -s without relative paths' '
 	test_cmp expect output &&
 
 	git status -s --ignored >output &&
-	grep "^!! \"expect with spaces\"$" output &&
+	test_grep "^!! \"expect with spaces\"$" output &&
 	grep -v "^!! " output >output-wo-ignored &&
 	test_cmp expect output-wo-ignored
 '
@@ -908,7 +908,7 @@ test_expect_success 'status shows detached HEAD properly after checking out non-
 	git clone upstream downstream &&
 	git -C downstream checkout @{u} &&
 	git -C downstream status >actual &&
-	grep -E "HEAD detached at [0-9a-f]+" actual
+	test_grep -E "HEAD detached at [0-9a-f]+" actual
 '
 
 test_expect_success 'setup status submodule summary' '
@@ -1127,7 +1127,7 @@ test_expect_success POSIXPERM,SANITY 'status succeeds in a read-only repository'
 		# make dir1/tracked stat-dirty
 		>dir1/tracked1 && mv -f dir1/tracked1 dir1/tracked &&
 		git status -s >output &&
-		! grep dir1/tracked output &&
+		test_grep ! dir1/tracked output &&
 		# make sure "status" succeeded without writing index out
 		git diff-files | grep dir1/tracked
 	)
diff --git a/t/t7510-signed-commit.sh b/t/t7510-signed-commit.sh
index aa9108da54..41adb0109d 100755
--- a/t/t7510-signed-commit.sh
+++ b/t/t7510-signed-commit.sh
@@ -89,8 +89,8 @@ test_expect_success GPG 'verify and show signatures' '
 		do
 			git verify-commit $commit &&
 			git show --pretty=short --show-signature $commit >actual &&
-			grep "Good signature from" actual &&
-			! grep "BAD signature from" actual &&
+			test_grep "Good signature from" actual &&
+			test_grep ! "BAD signature from" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -100,8 +100,8 @@ test_expect_success GPG 'verify and show signatures' '
 		do
 			test_must_fail git verify-commit $commit &&
 			git show --pretty=short --show-signature $commit >actual &&
-			! grep "Good signature from" actual &&
-			! grep "BAD signature from" actual &&
+			test_grep ! "Good signature from" actual &&
+			test_grep ! "BAD signature from" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -109,9 +109,9 @@ test_expect_success GPG 'verify and show signatures' '
 		for commit in eighth-signed-alt twelfth-signed-alt
 		do
 			git show --pretty=short --show-signature $commit >actual &&
-			grep "Good signature from" actual &&
-			! grep "BAD signature from" actual &&
-			grep "not certified" actual &&
+			test_grep "Good signature from" actual &&
+			test_grep ! "BAD signature from" actual &&
+			test_grep "not certified" actual &&
 			echo $commit OK || exit 1
 		done
 	)
@@ -119,16 +119,16 @@ test_expect_success GPG 'verify and show signatures' '
 
 test_expect_success GPG 'verify-commit exits failure on unknown signature' '
 	test_must_fail env GNUPGHOME="$GNUPGHOME_NOT_USED" git verify-commit initial 2>actual &&
-	! grep "Good signature from" actual &&
-	! grep "BAD signature from" actual &&
-	grep -q -F -e "No public key" -e "public key not found" actual
+	test_grep ! "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual &&
+	test_grep -F -e "No public key" -e "public key not found" actual
 '
 
 test_expect_success GPG 'verify-commit exits success on untrusted signature' '
 	git verify-commit eighth-signed-alt 2>actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual &&
-	grep "not certified" actual
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual &&
+	test_grep "not certified" actual
 '
 
 test_expect_success GPG 'verify-commit exits success with matching minTrustLevel' '
@@ -151,8 +151,8 @@ test_expect_success GPG 'verify signatures with --raw' '
 		for commit in initial second merge fourth-signed fifth-signed sixth-signed seventh-signed
 		do
 			git verify-commit --raw $commit 2>actual &&
-			grep "GOODSIG" actual &&
-			! grep "BADSIG" actual &&
+			test_grep "GOODSIG" actual &&
+			test_grep ! "BADSIG" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -160,8 +160,8 @@ test_expect_success GPG 'verify signatures with --raw' '
 		for commit in merge^2 fourth-unsigned sixth-unsigned seventh-unsigned
 		do
 			test_must_fail git verify-commit --raw $commit 2>actual &&
-			! grep "GOODSIG" actual &&
-			! grep "BADSIG" actual &&
+			test_grep ! "GOODSIG" actual &&
+			test_grep ! "BADSIG" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -169,9 +169,9 @@ test_expect_success GPG 'verify signatures with --raw' '
 		for commit in eighth-signed-alt
 		do
 			git verify-commit --raw $commit 2>actual &&
-			grep "GOODSIG" actual &&
-			! grep "BADSIG" actual &&
-			grep "TRUST_UNDEFINED" actual &&
+			test_grep "GOODSIG" actual &&
+			test_grep ! "BADSIG" actual &&
+			test_grep "TRUST_UNDEFINED" actual &&
 			echo $commit OK || exit 1
 		done
 	)
@@ -179,7 +179,7 @@ test_expect_success GPG 'verify signatures with --raw' '
 
 test_expect_success GPG 'proper header is used for hash algorithm' '
 	git cat-file commit fourth-signed >output &&
-	grep "^$(test_oid header) -----BEGIN PGP SIGNATURE-----" output
+	test_grep "^$(test_oid header) -----BEGIN PGP SIGNATURE-----" output
 '
 
 test_expect_success GPG 'show signed commit with signature' '
@@ -201,8 +201,8 @@ test_expect_success GPG 'detect fudged signature' '
 	git hash-object -w -t commit forged1 >forged1.commit &&
 	test_must_fail git verify-commit $(cat forged1.commit) &&
 	git show --pretty=short --show-signature $(cat forged1.commit) >actual1 &&
-	grep "BAD signature from" actual1 &&
-	! grep "Good signature from" actual1
+	test_grep "BAD signature from" actual1 &&
+	test_grep ! "Good signature from" actual1
 '
 
 test_expect_success GPG 'detect fudged signature with NUL' '
@@ -212,8 +212,8 @@ test_expect_success GPG 'detect fudged signature with NUL' '
 	git hash-object --literally -w -t commit forged2 >forged2.commit &&
 	test_must_fail git verify-commit $(cat forged2.commit) &&
 	git show --pretty=short --show-signature $(cat forged2.commit) >actual2 &&
-	grep "BAD signature from" actual2 &&
-	! grep "Good signature from" actual2
+	test_grep "BAD signature from" actual2 &&
+	test_grep ! "Good signature from" actual2
 '
 
 test_expect_success GPG 'amending already signed commit' '
@@ -221,8 +221,8 @@ test_expect_success GPG 'amending already signed commit' '
 	git commit --amend -S --no-edit &&
 	git verify-commit HEAD &&
 	git show -s --show-signature HEAD >actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual
 '
 
 test_expect_success GPG2 'bare signature' '
@@ -326,8 +326,8 @@ test_expect_success GPG 'show lack of signature with custom format' '
 test_expect_success GPG 'log.showsignature behaves like --show-signature' '
 	test_config log.showsignature true &&
 	git show initial >actual &&
-	grep "gpg: Signature made" actual &&
-	grep "gpg: Good signature" actual
+	test_grep "gpg: Signature made" actual &&
+	test_grep "gpg: Good signature" actual
 '
 
 test_expect_success GPG 'check config gpg.format values' '
@@ -349,8 +349,8 @@ test_expect_success GPG 'detect fudged commit with double signature' '
 	git hash-object -w -t commit double-commit >double-commit.commit &&
 	test_must_fail git verify-commit $(cat double-commit.commit) &&
 	git show --pretty=short --show-signature $(cat double-commit.commit) >double-actual &&
-	grep "BAD signature from" double-actual &&
-	grep "Good signature from" double-actual
+	test_grep "BAD signature from" double-actual &&
+	test_grep "Good signature from" double-actual
 '
 
 test_expect_success GPG 'show double signature with custom format' '
@@ -404,8 +404,8 @@ test_expect_success GPG 'verify-commit verifies multiply signed commits' '
 	head=$(git hash-object -t commit -w commit) &&
 	git reset --hard $head &&
 	git verify-commit $head 2>actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual
 '
 
 test_expect_success 'custom `gpg.program`' '
@@ -449,7 +449,7 @@ test_expect_success 'custom `gpg.program`' '
 
 	test_must_fail env LET_GPG_PROGRAM_FAIL=1 \
 	git commit -S --allow-empty -m must-fail 2>err &&
-	grep zOMG err &&
+	test_grep zOMG err &&
 
 	# `gpg.program` starts with `~`, the path should be interpreted to be relative to `$HOME`
 	test_config gpg.program "~/fake-gpg" &&
diff --git a/t/t7516-commit-races.sh b/t/t7516-commit-races.sh
index de7c4ca790..29669f64ae 100755
--- a/t/t7516-commit-races.sh
+++ b/t/t7516-commit-races.sh
@@ -10,7 +10,7 @@ test_expect_success 'race to create orphan commit' '
 	EOF
 	test_must_fail env EDITOR=./hare-editor git commit --allow-empty -m tortoise -e &&
 	git show -s --pretty=format:%s >subject &&
-	grep hare subject &&
+	test_grep hare subject &&
 	git show -s --pretty=format:%P >out &&
 	test_must_be_empty out
 '
@@ -24,7 +24,7 @@ test_expect_success 'race to create non-orphan commit' '
 	git rev-parse HEAD >base &&
 	test_must_fail env EDITOR=./airplane-editor git commit --allow-empty -m ship -e &&
 	git show -s --pretty=format:%s >subject &&
-	grep airplane subject &&
+	test_grep airplane subject &&
 	git rev-parse HEAD^ >parent &&
 	test_cmp base parent
 '
diff --git a/t/t7519-status-fsmonitor.sh b/t/t7519-status-fsmonitor.sh
index 7ee69ecdd4..93973ed25a 100755
--- a/t/t7519-status-fsmonitor.sh
+++ b/t/t7519-status-fsmonitor.sh
@@ -63,19 +63,19 @@ test_expect_success 'incompatible bare repo' '
 	test_must_fail \
 		git -C ./bare-clone -c core.fsmonitor=foo \
 			update-index --fsmonitor 2>actual &&
-	grep "bare repository .* is incompatible with fsmonitor" actual &&
+	test_grep "bare repository .* is incompatible with fsmonitor" actual &&
 
 	test_must_fail \
 		git -C ./bare-clone -c core.fsmonitor=true \
 			update-index --fsmonitor 2>actual &&
-	grep "bare repository .* is incompatible with fsmonitor" actual
+	test_grep "bare repository .* is incompatible with fsmonitor" actual
 '
 
 test_expect_success FSMONITOR_DAEMON 'run fsmonitor-daemon in bare repo' '
 	test_when_finished "rm -rf ./bare-clone actual" &&
 	git init --bare bare-clone &&
 	test_must_fail git -C ./bare-clone fsmonitor--daemon run 2>actual &&
-	grep "bare repository .* is incompatible with fsmonitor" actual
+	test_grep "bare repository .* is incompatible with fsmonitor" actual
 '
 
 test_expect_success MINGW,FSMONITOR_DAEMON 'run fsmonitor-daemon in virtual repo' '
@@ -84,7 +84,7 @@ test_expect_success MINGW,FSMONITOR_DAEMON 'run fsmonitor-daemon in virtual repo
 	test_must_fail git -C ./fake-virtual-clone \
 			   -c core.virtualfilesystem=true \
 			   fsmonitor--daemon run 2>actual &&
-	grep "virtual repository .* is incompatible with fsmonitor" actual
+	test_grep "virtual repository .* is incompatible with fsmonitor" actual
 '
 
 test_expect_success 'setup' '
@@ -111,21 +111,21 @@ test_expect_success 'setup' '
 # test that the fsmonitor extension is off by default
 test_expect_success 'fsmonitor extension is off by default' '
 	test-tool dump-fsmonitor >actual &&
-	grep "^no fsmonitor" actual
+	test_grep "^no fsmonitor" actual
 '
 
 # test that "update-index --fsmonitor" adds the fsmonitor extension
 test_expect_success 'update-index --fsmonitor" adds the fsmonitor extension' '
 	git update-index --fsmonitor &&
 	test-tool dump-fsmonitor >actual &&
-	grep "^fsmonitor last update" actual
+	test_grep "^fsmonitor last update" actual
 '
 
 # test that "update-index --no-fsmonitor" removes the fsmonitor extension
 test_expect_success 'update-index --no-fsmonitor" removes the fsmonitor extension' '
 	git update-index --no-fsmonitor &&
 	test-tool dump-fsmonitor >actual &&
-	grep "^no fsmonitor" actual
+	test_grep "^no fsmonitor" actual
 '
 
 cat >expect <<EOF &&
diff --git a/t/t7527-builtin-fsmonitor.sh b/t/t7527-builtin-fsmonitor.sh
index b63c162f9b..901724938c 100755
--- a/t/t7527-builtin-fsmonitor.sh
+++ b/t/t7527-builtin-fsmonitor.sh
@@ -46,7 +46,7 @@ verify_fsmonitor_works () {
 			--token 0 >/dev/null 2>&1
 	maybe_timeout 5 \
 		git -C test_fsmonitor_smoke fsmonitor--daemon stop 2>/dev/null
-	! grep -q "cookie_wait timed out" "$PWD/smoke.trace" 2>/dev/null
+	! grep -q "cookie_wait timed out" "$PWD/smoke.trace" 2>/dev/null # lint-ok: $? capture
 	ret=$?
 	rm -rf test_fsmonitor_smoke smoke.trace
 	return $ret
@@ -157,7 +157,7 @@ test_expect_success 'implicit daemon start' '
 	GIT_TRACE2_EVENT="$PWD/.git/trace" \
 		test-tool -C test_implicit fsmonitor-client query --token 0 >actual &&
 	nul_to_q <actual >actual.filtered &&
-	grep "builtin:" actual.filtered &&
+	test_grep "builtin:" actual.filtered &&
 
 	# confirm that a daemon was started in the background.
 	#
@@ -311,7 +311,7 @@ test_expect_success 'cannot start multiple daemons' '
 	start_daemon -C test_multiple &&
 
 	test_must_fail git -C test_multiple fsmonitor--daemon start 2>actual &&
-	grep "fsmonitor--daemon is already running" actual &&
+	test_grep "fsmonitor--daemon is already running" actual &&
 
 	git -C test_multiple fsmonitor--daemon stop &&
 	test_must_fail git -C test_multiple fsmonitor--daemon status
@@ -621,7 +621,7 @@ test_expect_success 'flush cached data' '
 	test-tool -C test_flush fsmonitor-client query --token "builtin:test_00000001:0" >actual_1 &&
 	nul_to_q <actual_1 >actual_q1 &&
 
-	grep "file_1" actual_q1 &&
+	test_grep "file_1" actual_q1 &&
 
 	# Force a flush.  This will change the <token_id>, reset the <seq_nr>, and
 	# flush the file data.  Then create some events and ensure that the file
@@ -629,19 +629,19 @@ test_expect_success 'flush cached data' '
 
 	test-tool -C test_flush fsmonitor-client flush >flush_0 &&
 	nul_to_q <flush_0 >flush_q0 &&
-	grep "^builtin:test_00000002:0Q/Q$" flush_q0 &&
+	test_grep "^builtin:test_00000002:0Q/Q$" flush_q0 &&
 
 	test-tool -C test_flush fsmonitor-client query --token "builtin:test_00000002:0" >actual_2 &&
 	nul_to_q <actual_2 >actual_q2 &&
 
-	grep "^builtin:test_00000002:0Q$" actual_q2 &&
+	test_grep "^builtin:test_00000002:0Q$" actual_q2 &&
 
 	>test_flush/file_3 &&
 
 	test-tool -C test_flush fsmonitor-client query --token "builtin:test_00000002:0" >actual_3 &&
 	nul_to_q <actual_3 >actual_q3 &&
 
-	grep "file_3" actual_q3
+	test_grep "file_3" actual_q3
 '
 
 # The next few test cases create repos where the .git directory is NOT
@@ -814,7 +814,7 @@ do
 
 		start_daemon -C "$u" &&
 		git -C "$u" status >actual &&
-		grep "new file:   file1" actual
+		test_grep "new file:   file1" actual
 	'
 done
 
@@ -1068,9 +1068,9 @@ test_expect_success CASE_INSENSITIVE_FS 'case insensitive+preserving' '
 	# directories and files that we touched.  We may or may not get a
 	# trailing slash on modified directories.
 	#
-	grep -E "^event: abc/?$"       ./insensitive.trace &&
-	grep -E "^event: abc/def/?$"   ./insensitive.trace &&
-	grep -E "^event: abc/def/xyz$" ./insensitive.trace
+	test_grep -E "^event: abc/?$"       ./insensitive.trace &&
+	test_grep -E "^event: abc/def/?$"   ./insensitive.trace &&
+	test_grep -E "^event: abc/def/xyz$" ./insensitive.trace
 '
 
 # The variable "unicode_debug" is defined in the following library
@@ -1112,20 +1112,20 @@ test_expect_success !UNICODE_COMPOSITION_SENSITIVE 'Unicode nfc/nfd' '
 	then
 		# We should have seen NFC event from OS.
 		# We should not have synthesized an NFD event.
-		grep -E    "^event: nfc/c_${utf8_nfc}/?$" ./unicode.trace &&
-		grep -E -v "^event: nfc/c_${utf8_nfd}/?$" ./unicode.trace
+		test_grep -E    "^event: nfc/c_${utf8_nfc}/?$" ./unicode.trace &&
+		test_grep -E -v "^event: nfc/c_${utf8_nfd}/?$" ./unicode.trace
 	else
 		# We should have seen NFD event from OS.
 		# We should have synthesized an NFC event.
-		grep -E "^event: nfc/c_${utf8_nfd}/?$" ./unicode.trace &&
-		grep -E "^event: nfc/c_${utf8_nfc}/?$" ./unicode.trace
+		test_grep -E "^event: nfc/c_${utf8_nfd}/?$" ./unicode.trace &&
+		test_grep -E "^event: nfc/c_${utf8_nfc}/?$" ./unicode.trace
 	fi &&
 
 	# We assume UNICODE_NFD_PRESERVED.
 	# We should have seen explicit NFD from OS.
 	# We should have synthesized an NFC event.
-	grep -E "^event: nfd/d_${utf8_nfd}/?$" ./unicode.trace &&
-	grep -E "^event: nfd/d_${utf8_nfc}/?$" ./unicode.trace
+	test_grep -E "^event: nfd/d_${utf8_nfd}/?$" ./unicode.trace &&
+	test_grep -E "^event: nfd/d_${utf8_nfc}/?$" ./unicode.trace
 '
 
 test_expect_success 'split-index and FSMonitor work well together' '
@@ -1239,21 +1239,21 @@ test_expect_success CASE_INSENSITIVE_FS 'fsmonitor subdir case wrong on disk' '
 		<"$PWD/subdir_case_wrong.log" \
 		>"$PWD/subdir_case_wrong.log1" &&
 
-	grep -q "AAA.*pos 0" "$PWD/subdir_case_wrong.log1" &&
-	grep -q "zzz.*pos 6" "$PWD/subdir_case_wrong.log1" &&
+	test_grep "AAA.*pos 0" "$PWD/subdir_case_wrong.log1" &&
+	test_grep "zzz.*pos 6" "$PWD/subdir_case_wrong.log1" &&
 
-	grep -q "dir1/DIR2/dir3/file3.*pos -3" "$PWD/subdir_case_wrong.log1" &&
+	test_grep "dir1/DIR2/dir3/file3.*pos -3" "$PWD/subdir_case_wrong.log1" &&
 
 	# Verify that we get a mapping event to correct the case.
-	grep -q "MAP:.*dir1/DIR2/dir3/file3.*dir1/dir2/dir3/file3" \
+	test_grep "MAP:.*dir1/DIR2/dir3/file3.*dir1/dir2/dir3/file3" \
 		"$PWD/subdir_case_wrong.log1" &&
 
 	# The refresh-callbacks should have caused "git status" to clear
 	# the CE_FSMONITOR_VALID bit on each of those files and caused
 	# the worktree scan to visit them and mark them as modified.
-	grep -q " M AAA" "$PWD/subdir_case_wrong.out" &&
-	grep -q " M zzz" "$PWD/subdir_case_wrong.out" &&
-	grep -q " M dir1/dir2/dir3/file3" "$PWD/subdir_case_wrong.out"
+	test_grep " M AAA" "$PWD/subdir_case_wrong.out" &&
+	test_grep " M zzz" "$PWD/subdir_case_wrong.out" &&
+	test_grep " M dir1/dir2/dir3/file3" "$PWD/subdir_case_wrong.out"
 '
 
 test_expect_success CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
@@ -1326,10 +1326,10 @@ test_expect_success CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
 	GIT_TRACE_FSMONITOR="$PWD/file_case_wrong-try1.log" \
 		git -C file_case_wrong status --short \
 			>"$PWD/file_case_wrong-try1.out" &&
-	grep -q "fsmonitor_refresh_callback.*FILE-3-A.*pos -3" "$PWD/file_case_wrong-try1.log" &&
-	grep -q "fsmonitor_refresh_callback.*file-3-a.*pos 4"  "$PWD/file_case_wrong-try1.log" &&
-	grep -q "fsmonitor_refresh_callback.*FILE-4-A.*pos 6"  "$PWD/file_case_wrong-try1.log" &&
-	grep -q "fsmonitor_refresh_callback.*file-4-a.*pos -9" "$PWD/file_case_wrong-try1.log" &&
+	test_grep "fsmonitor_refresh_callback.*FILE-3-A.*pos -3" "$PWD/file_case_wrong-try1.log" &&
+	test_grep "fsmonitor_refresh_callback.*file-3-a.*pos 4"  "$PWD/file_case_wrong-try1.log" &&
+	test_grep "fsmonitor_refresh_callback.*FILE-4-A.*pos 6"  "$PWD/file_case_wrong-try1.log" &&
+	test_grep "fsmonitor_refresh_callback.*file-4-a.*pos -9" "$PWD/file_case_wrong-try1.log" &&
 
 	# FSM refresh will have invalidated the FSM bit and cause a regular
 	# (real) scan of these tracked files, so they should have "H" status.
@@ -1337,8 +1337,8 @@ test_expect_success CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
 	# command).)
 
 	git -C file_case_wrong ls-files -f >"$PWD/file_case_wrong-lsf1.out" &&
-	grep -q "H dir1/dir2/dir3/file-3-a" "$PWD/file_case_wrong-lsf1.out" &&
-	grep -q "H dir1/dir2/dir4/FILE-4-A" "$PWD/file_case_wrong-lsf1.out" &&
+	test_grep "H dir1/dir2/dir3/file-3-a" "$PWD/file_case_wrong-lsf1.out" &&
+	test_grep "H dir1/dir2/dir4/FILE-4-A" "$PWD/file_case_wrong-lsf1.out" &&
 
 
 	# Try the status again. We assume that the above status command
@@ -1347,17 +1347,17 @@ test_expect_success CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
 	GIT_TRACE_FSMONITOR="$PWD/file_case_wrong-try2.log" \
 		git -C file_case_wrong status --short \
 			>"$PWD/file_case_wrong-try2.out" &&
-	! grep -q "fsmonitor_refresh_callback.*FILE-3-A.*pos" "$PWD/file_case_wrong-try2.log" &&
-	! grep -q "fsmonitor_refresh_callback.*file-3-a.*pos" "$PWD/file_case_wrong-try2.log" &&
-	! grep -q "fsmonitor_refresh_callback.*FILE-4-A.*pos" "$PWD/file_case_wrong-try2.log" &&
-	! grep -q "fsmonitor_refresh_callback.*file-4-a.*pos" "$PWD/file_case_wrong-try2.log" &&
+	test_grep ! "fsmonitor_refresh_callback.*FILE-3-A.*pos" "$PWD/file_case_wrong-try2.log" &&
+	test_grep ! "fsmonitor_refresh_callback.*file-3-a.*pos" "$PWD/file_case_wrong-try2.log" &&
+	test_grep ! "fsmonitor_refresh_callback.*FILE-4-A.*pos" "$PWD/file_case_wrong-try2.log" &&
+	test_grep ! "fsmonitor_refresh_callback.*file-4-a.*pos" "$PWD/file_case_wrong-try2.log" &&
 
 	# FSM refresh saw nothing, so it will mark all files as valid,
 	# so they should now have "h" status.
 
 	git -C file_case_wrong ls-files -f >"$PWD/file_case_wrong-lsf2.out" &&
-	grep -q "h dir1/dir2/dir3/file-3-a" "$PWD/file_case_wrong-lsf2.out" &&
-	grep -q "h dir1/dir2/dir4/FILE-4-A" "$PWD/file_case_wrong-lsf2.out" &&
+	test_grep "h dir1/dir2/dir3/file-3-a" "$PWD/file_case_wrong-lsf2.out" &&
+	test_grep "h dir1/dir2/dir4/FILE-4-A" "$PWD/file_case_wrong-lsf2.out" &&
 
 
 	# We now have files with clean content, but with case-incorrect
@@ -1372,20 +1372,20 @@ test_expect_success CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
 			>"$PWD/file_case_wrong-try3.out" &&
 
 	# Verify that we get a mapping event to correct the case.
-	grep -q "fsmonitor_refresh_callback MAP:.*dir1/dir2/dir3/FILE-3-A.*dir1/dir2/dir3/file-3-a" \
+	test_grep "fsmonitor_refresh_callback MAP:.*dir1/dir2/dir3/FILE-3-A.*dir1/dir2/dir3/file-3-a" \
 		"$PWD/file_case_wrong-try3.log" &&
-	grep -q "fsmonitor_refresh_callback MAP:.*dir1/dir2/dir4/file-4-a.*dir1/dir2/dir4/FILE-4-A" \
+	test_grep "fsmonitor_refresh_callback MAP:.*dir1/dir2/dir4/file-4-a.*dir1/dir2/dir4/FILE-4-A" \
 		"$PWD/file_case_wrong-try3.log" &&
 
 	# FSEvents are in observed case.
-	grep -q "fsmonitor_refresh_callback.*FILE-3-A.*pos -3" "$PWD/file_case_wrong-try3.log" &&
-	grep -q "fsmonitor_refresh_callback.*file-4-a.*pos -9" "$PWD/file_case_wrong-try3.log" &&
+	test_grep "fsmonitor_refresh_callback.*FILE-3-A.*pos -3" "$PWD/file_case_wrong-try3.log" &&
+	test_grep "fsmonitor_refresh_callback.*file-4-a.*pos -9" "$PWD/file_case_wrong-try3.log" &&
 
 	# The refresh-callbacks should have caused "git status" to clear
 	# the CE_FSMONITOR_VALID bit on each of those files and caused
 	# the worktree scan to visit them and mark them as modified.
-	grep -q " M dir1/dir2/dir3/file-3-a" "$PWD/file_case_wrong-try3.out" &&
-	grep -q " M dir1/dir2/dir4/FILE-4-A" "$PWD/file_case_wrong-try3.out"
+	test_grep " M dir1/dir2/dir3/file-3-a" "$PWD/file_case_wrong-try3.out" &&
+	test_grep " M dir1/dir2/dir4/FILE-4-A" "$PWD/file_case_wrong-try3.out"
 '
 
 test_done
diff --git a/t/t7528-signed-commit-ssh.sh b/t/t7528-signed-commit-ssh.sh
index b50306b9b3..44396460e6 100755
--- a/t/t7528-signed-commit-ssh.sh
+++ b/t/t7528-signed-commit-ssh.sh
@@ -133,8 +133,8 @@ test_expect_success GPGSSH 'verify and show signatures' '
 		do
 			git verify-commit $commit &&
 			git show --pretty=short --show-signature $commit >actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -144,8 +144,8 @@ test_expect_success GPGSSH 'verify and show signatures' '
 		do
 			test_must_fail git verify-commit $commit &&
 			git show --pretty=short --show-signature $commit >actual &&
-			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -153,9 +153,9 @@ test_expect_success GPGSSH 'verify and show signatures' '
 		for commit in eighth-signed-alt twelfth-signed-alt
 		do
 			git show --pretty=short --show-signature $commit >actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
-			grep "${GPGSSH_KEY_NOT_TRUSTED}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_KEY_NOT_TRUSTED}" actual &&
 			echo $commit OK || exit 1
 		done
 	)
@@ -164,34 +164,34 @@ test_expect_success GPGSSH 'verify and show signatures' '
 test_expect_success GPGSSH 'verify-commit exits failure on untrusted signature' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_must_fail git verify-commit eighth-signed-alt 2>actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
-	grep "${GPGSSH_KEY_NOT_TRUSTED}" actual
+	test_grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
+	test_grep "${GPGSSH_KEY_NOT_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-commit exits failure on expired signature key' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_must_fail git verify-commit expired-signed 2>actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-commit exits failure on not yet valid signature key' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_must_fail git verify-commit notyetvalid-signed 2>actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-commit succeeds with commit date and key validity matching' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git verify-commit timeboxedvalid-signed 2>actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual
 '
 
 test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-commit exits failure with commit date outside of key validity' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_must_fail git verify-commit timeboxedinvalid-signed 2>actual &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH 'verify-commit exits success with matching minTrustLevel' '
@@ -217,8 +217,8 @@ test_expect_success GPGSSH 'verify signatures with --raw' '
 		for commit in initial second merge fourth-signed fifth-signed sixth-signed seventh-signed
 		do
 			git verify-commit --raw $commit 2>actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -226,8 +226,8 @@ test_expect_success GPGSSH 'verify signatures with --raw' '
 		for commit in merge^2 fourth-unsigned sixth-unsigned seventh-unsigned
 		do
 			test_must_fail git verify-commit --raw $commit 2>actual &&
-			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $commit OK || exit 1
 		done
 	) &&
@@ -235,8 +235,8 @@ test_expect_success GPGSSH 'verify signatures with --raw' '
 		for commit in eighth-signed-alt
 		do
 			test_must_fail git verify-commit --raw $commit 2>actual &&
-			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
-			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			test_grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual &&
 			echo $commit OK || exit 1
 		done
 	)
@@ -244,7 +244,7 @@ test_expect_success GPGSSH 'verify signatures with --raw' '
 
 test_expect_success GPGSSH 'proper header is used for hash algorithm' '
 	git cat-file commit fourth-signed >output &&
-	grep "^$(test_oid header) -----BEGIN SSH SIGNATURE-----" output
+	test_grep "^$(test_oid header) -----BEGIN SSH SIGNATURE-----" output
 '
 
 test_expect_success GPGSSH 'show signed commit with signature' '
@@ -268,9 +268,9 @@ test_expect_success GPGSSH 'detect fudged signature' '
 	git hash-object -w -t commit forged1 >forged1.commit &&
 	test_must_fail git verify-commit $(cat forged1.commit) &&
 	git show --pretty=short --show-signature $(cat forged1.commit) >actual1 &&
-	grep "${GPGSSH_BAD_SIGNATURE}" actual1 &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual1 &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual1
+	test_grep "${GPGSSH_BAD_SIGNATURE}" actual1 &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual1 &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual1
 '
 
 test_expect_success GPGSSH 'detect fudged signature with NUL' '
@@ -281,8 +281,8 @@ test_expect_success GPGSSH 'detect fudged signature with NUL' '
 	git hash-object --literally -w -t commit forged2 >forged2.commit &&
 	test_must_fail git verify-commit $(cat forged2.commit) &&
 	git show --pretty=short --show-signature $(cat forged2.commit) >actual2 &&
-	grep "${GPGSSH_BAD_SIGNATURE}" actual2 &&
-	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual2
+	test_grep "${GPGSSH_BAD_SIGNATURE}" actual2 &&
+	test_grep ! "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual2
 '
 
 test_expect_success GPGSSH 'amending already signed commit' '
@@ -293,8 +293,8 @@ test_expect_success GPGSSH 'amending already signed commit' '
 	git commit --amend -S --no-edit &&
 	git verify-commit HEAD &&
 	git show -s --show-signature HEAD >actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
-	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	test_grep ! "${GPGSSH_BAD_SIGNATURE}" actual
 '
 
 test_expect_success GPGSSH 'show good signature with custom format' '
@@ -386,7 +386,7 @@ test_expect_success GPGSSH 'log.showsignature behaves like --show-signature' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	test_config log.showsignature true &&
 	git show initial >actual &&
-	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+	test_grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
 '
 
 test_expect_success GPGSSH 'check config gpg.format values' '
@@ -410,8 +410,8 @@ test_expect_failure GPGSSH 'detect fudged commit with double signature (TODO)' '
 	git hash-object -w -t commit double-commit >double-commit.commit &&
 	test_must_fail git verify-commit $(cat double-commit.commit) &&
 	git show --pretty=short --show-signature $(cat double-commit.commit) >double-actual &&
-	grep "BAD signature from" double-actual &&
-	grep "Good signature from" double-actual
+	test_grep "BAD signature from" double-actual &&
+	test_grep "Good signature from" double-actual
 '
 
 test_expect_failure GPGSSH 'show double signature with custom format (TODO)' '
@@ -463,8 +463,8 @@ test_expect_failure GPGSSH 'verify-commit verifies multiply signed commits (TODO
 	head=$(git hash-object -t commit -w commit) &&
 	git reset --hard $head &&
 	git verify-commit $head 2>actual &&
-	grep "Good signature from" actual &&
-	! grep "BAD signature from" actual
+	test_grep "Good signature from" actual &&
+	test_grep ! "BAD signature from" actual
 '
 
 test_done
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index f877d9a433..a9c3c3920d 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -342,8 +342,8 @@ test_expect_success 'merge --squash --autostash conflict does not attempt to app
 	>unrelated &&
 	git add unrelated &&
 	test_must_fail git merge --squash c7 --autostash >out 2>err &&
-	! grep "Applying autostash resulted in conflicts." err &&
-	grep "When finished, apply stashed changes with \`git stash pop\`" out
+	test_grep ! "Applying autostash resulted in conflicts." err &&
+	test_grep "When finished, apply stashed changes with \`git stash pop\`" out
 '
 
 test_expect_success 'merge c3 with c7 with commit.cleanup = scissors' '
@@ -990,7 +990,7 @@ test_expect_success 'merge --no-ff --edit' '
 	EDITOR=./editor git merge --no-ff --edit c1 &&
 	verify_parents $c0 $c1 &&
 	git cat-file commit HEAD >raw &&
-	grep "work done on the side branch" raw &&
+	test_grep "work done on the side branch" raw &&
 	sed "1,/^$/d" >actual raw &&
 	test_cmp expected actual
 '
@@ -1157,13 +1157,13 @@ test_expect_success 'merge suggests matching remote refname' '
 	git pack-refs --all --prune &&
 
 	test_must_fail git merge not-local 2>stderr &&
-	grep origin/not-local stderr
+	test_grep origin/not-local stderr
 '
 
 test_expect_success 'suggested names are not ambiguous' '
 	git update-ref refs/heads/origin/not-local HEAD &&
 	test_must_fail git merge not-local 2>stderr &&
-	grep remotes/origin/not-local stderr
+	test_grep remotes/origin/not-local stderr
 '
 
 test_done
diff --git a/t/t7603-merge-reduce-heads.sh b/t/t7603-merge-reduce-heads.sh
index 1f8c3b7ccb..92007dc501 100755
--- a/t/t7603-merge-reduce-heads.sh
+++ b/t/t7603-merge-reduce-heads.sh
@@ -59,11 +59,11 @@ test_expect_success 'merge c1 with c2, c3, c4, c5' '
 	test_path_is_file c4.c &&
 	test_path_is_file c5.c &&
 	git show --format=%s -s >actual &&
-	! grep c1 actual &&
-	grep c2 actual &&
-	grep c3 actual &&
-	! grep c4 actual &&
-	grep c5 actual
+	test_grep ! c1 actual &&
+	test_grep c2 actual &&
+	test_grep c3 actual &&
+	test_grep ! c4 actual &&
+	test_grep c5 actual
 '
 
 test_expect_success 'pull c2, c3, c4, c5 into c1' '
@@ -82,11 +82,11 @@ test_expect_success 'pull c2, c3, c4, c5 into c1' '
 	test_path_is_file c4.c &&
 	test_path_is_file c5.c &&
 	git show --format=%s -s >actual &&
-	! grep c1 actual &&
-	grep c2 actual &&
-	grep c3 actual &&
-	! grep c4 actual &&
-	grep c5 actual
+	test_grep ! c1 actual &&
+	test_grep c2 actual &&
+	test_grep c3 actual &&
+	test_grep ! c4 actual &&
+	test_grep c5 actual
 '
 
 test_expect_success 'setup' '
diff --git a/t/t7606-merge-custom.sh b/t/t7606-merge-custom.sh
index 81fb7c474c..0ae2f59b1d 100755
--- a/t/t7606-merge-custom.sh
+++ b/t/t7606-merge-custom.sh
@@ -60,7 +60,7 @@ test_expect_success 'merge c2 with a custom strategy' '
 	test_cmp second-parent.expected second-parent &&
 	test_cmp tree.expected tree &&
 	test -f c0.c &&
-	grep c1c1 c1.c &&
+	test_grep c1c1 c1.c &&
 	test -f c2.c
 '
 
diff --git a/t/t7607-merge-state.sh b/t/t7607-merge-state.sh
index 89a62ac53b..bfe782d89e 100755
--- a/t/t7607-merge-state.sh
+++ b/t/t7607-merge-state.sh
@@ -20,8 +20,8 @@ test_expect_success 'Ensure we restore original state if no merge strategy handl
 	# just hit conflicts, it completely fails and says that it cannot
 	# handle this type of merge.
 	test_expect_code 2 git merge branch2 branch3 >output 2>&1 &&
-	grep "fatal: merge program failed" output &&
-	grep "Should not be doing an octopus" output &&
+	test_grep "fatal: merge program failed" output &&
+	test_grep "Should not be doing an octopus" output &&
 
 	# Make sure we did not leave stray changes around when no appropriate
 	# merge strategy was found
diff --git a/t/t7610-mergetool.sh b/t/t7610-mergetool.sh
index 957f8e20ba..0128b14452 100755
--- a/t/t7610-mergetool.sh
+++ b/t/t7610-mergetool.sh
@@ -738,7 +738,7 @@ test_expect_success 'filenames seen by tools start with ./' '
 	test_config mergetool.myecho.trustExitCode true &&
 	test_must_fail git merge main &&
 	git mergetool --no-prompt --tool myecho -- both >actual &&
-	grep ^\./both_LOCAL_ actual
+	test_grep ^\./both_LOCAL_ actual
 '
 
 test_lazy_prereq MKTEMP '
@@ -755,8 +755,8 @@ test_expect_success MKTEMP 'temporary filenames are used with mergetool.writeToT
 	test_config mergetool.myecho.trustExitCode true &&
 	test_must_fail git merge main &&
 	git mergetool --no-prompt --tool myecho -- both >actual &&
-	! grep ^\./both_LOCAL_ actual &&
-	grep /both_LOCAL_ actual
+	test_grep ! ^\./both_LOCAL_ actual &&
+	test_grep /both_LOCAL_ actual
 '
 
 test_expect_success 'diff.orderFile configuration is honored' '
@@ -816,12 +816,12 @@ test_expect_success 'mergetool -Oorder-file is honored' '
 test_expect_success 'mergetool --tool-help shows recognized tools' '
 	# Check a few known tools are correctly shown
 	git mergetool --tool-help >mergetools &&
-	grep vimdiff mergetools &&
-	grep vimdiff3 mergetools &&
-	grep gvimdiff2 mergetools &&
-	grep araxis mergetools &&
-	grep xxdiff mergetools &&
-	grep meld mergetools
+	test_grep vimdiff mergetools &&
+	test_grep vimdiff3 mergetools &&
+	test_grep gvimdiff2 mergetools &&
+	test_grep araxis mergetools &&
+	test_grep xxdiff mergetools &&
+	test_grep meld mergetools
 '
 
 test_expect_success 'mergetool hideResolved' '
diff --git a/t/t7700-repack.sh b/t/t7700-repack.sh
index c6ff3aed30..47217e7cc4 100755
--- a/t/t7700-repack.sh
+++ b/t/t7700-repack.sh
@@ -177,7 +177,7 @@ test_expect_success 'packed unreachable obs in alternate ODB are not loosened' '
 	rm -f .git/objects/pack/* &&
 	mv pack-* .git/objects/pack/ &&
 	git verify-pack -v -- .git/objects/pack/*.idx >packlist &&
-	! grep "^$coid " packlist &&
+	test_grep ! "^$coid " packlist &&
 	echo >.git/objects/info/alternates &&
 	test_must_fail git show $coid
 '
@@ -194,7 +194,7 @@ test_expect_success 'local packed unreachable obs that exist in alternate ODB ar
 	rm -f .git/objects/pack/* &&
 	mv pack-* .git/objects/pack/ &&
 	git verify-pack -v -- .git/objects/pack/*.idx >packlist &&
-	! grep "^$coid " packlist &&
+	test_grep ! "^$coid " packlist &&
 	echo >.git/objects/info/alternates &&
 	test_must_fail git show $coid
 '
@@ -226,8 +226,8 @@ test_expect_success 'repack --keep-pack' '
 		test_line_count = 4 old-counts &&
 		git repack -a -d --keep-pack $P1 --keep-pack $P4 &&
 		ls .git/objects/pack/*.pack >new-counts &&
-		grep -q $P1 new-counts &&
-		grep -q $P4 new-counts &&
+		test_grep $P1 new-counts &&
+		test_grep $P4 new-counts &&
 		test_line_count = 3 new-counts &&
 		git fsck &&
 
@@ -276,7 +276,7 @@ test_expect_success 'repacking fails when missing .pack actually means missing o
 
 		test_must_fail git fsck &&
 		test_must_fail env GIT_COMMIT_GRAPH_PARANOIA=true git repack --cruft -d 2>err &&
-		grep "bad object" err &&
+		test_grep "bad object" err &&
 
 		# Before failing, the repack did not modify the
 		# pack directory.
@@ -460,8 +460,8 @@ test_expect_success '--filter works with --pack-kept-objects and .keep packs' '
 
 		# Object bar is in both the old .keep pack and the new
 		# pack that contained the filtered out objects
-		grep "$bar_pack" bar_pack_1 &&
-		grep "$foo_pack_1" bar_pack_1 &&
+		test_grep "$bar_pack" bar_pack_1 &&
+		test_grep "$foo_pack_1" bar_pack_1 &&
 		test "$foo_pack_1" != "$head_pack_1"
 	)
 '
diff --git a/t/t7703-repack-geometric.sh b/t/t7703-repack-geometric.sh
index 04d5d8fc33..d00715efcc 100755
--- a/t/t7703-repack-geometric.sh
+++ b/t/t7703-repack-geometric.sh
@@ -112,7 +112,7 @@ test_expect_success '--geometric with small-pack rollup' '
 		find $objdir/pack -name "*.pack" | sort >after &&
 		test_line_count = 3 after &&
 		comm -3 small before | tr -d "\t" >large &&
-		grep -qFf large after
+		test_grep -Ff large after
 	)
 '
 
@@ -210,7 +210,7 @@ test_expect_success '--geometric ignores --keep-pack packs' '
 
 		# Packs should not have changed (only one non-kept pack, no
 		# loose objects), but $midx should now exist.
-		grep "Nothing new to pack" out &&
+		test_grep "Nothing new to pack" out &&
 		test_path_is_file $midx &&
 
 		test_cmp packs.before packs.after &&
diff --git a/t/t7704-repack-cruft.sh b/t/t7704-repack-cruft.sh
index 9e03b04315..b342e82447 100755
--- a/t/t7704-repack-cruft.sh
+++ b/t/t7704-repack-cruft.sh
@@ -166,9 +166,9 @@ test_expect_success '--max-cruft-size creates new packs when too large' '
 		test-tool pack-mtimes $(basename "$cruft_foo") >foo.objects &&
 		test-tool pack-mtimes $(basename "$cruft_bar") >bar.objects &&
 
-		grep "^$foo" foo.objects &&
+		test_grep "^$foo" foo.objects &&
 		test_line_count = 1 foo.objects &&
-		grep "^$bar" bar.objects &&
+		test_grep "^$bar" bar.objects &&
 		test_line_count = 1 bar.objects
 	)
 '
@@ -188,8 +188,8 @@ test_expect_success '--max-cruft-size combines existing packs when not too large
 		cruft=$(ls $packdir/pack-*.mtimes) &&
 		test-tool pack-mtimes $(basename "$cruft") >cruft.objects &&
 
-		grep "^$foo" cruft.objects &&
-		grep "^$bar" cruft.objects &&
+		test_grep "^$foo" cruft.objects &&
+		test_grep "^$bar" cruft.objects &&
 		test_line_count = 2 cruft.objects
 	)
 '
@@ -693,7 +693,7 @@ test_expect_success 'cruft repack respects repack.cruftWindow' '
 		git -c pack.window=1 -c repack.cruftWindow=2 repack \
 		       --cruft --window=3 &&
 
-		grep "pack-objects.*--window=2.*--cruft" event.trace
+		test_grep "pack-objects.*--window=2.*--cruft" event.trace
 	)
 '
 
@@ -708,7 +708,7 @@ test_expect_success 'cruft repack respects --window by default' '
 		GIT_TRACE2_EVENT=$(pwd)/event.trace \
 		git -c pack.window=2 repack --cruft --window=3 &&
 
-		grep "pack-objects.*--window=3.*--cruft" event.trace
+		test_grep "pack-objects.*--window=3.*--cruft" event.trace
 	)
 '
 
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 8a91ff3603..02e47f466a 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -431,32 +431,32 @@ test_expect_success 'setup with 2 files different' '
 test_expect_success 'say no to the first file' '
 	(echo n && echo) >input &&
 	git difftool -x cat branch <input >output &&
-	grep m2 output &&
-	grep br2 output &&
-	! grep main output &&
-	! grep branch output
+	test_grep m2 output &&
+	test_grep br2 output &&
+	test_grep ! main output &&
+	test_grep ! branch output
 '
 
 test_expect_success 'say no to the second file' '
 	(echo && echo n) >input &&
 	git difftool -x cat branch <input >output &&
-	grep main output &&
-	grep branch output &&
-	! grep m2 output &&
-	! grep br2 output
+	test_grep main output &&
+	test_grep branch output &&
+	test_grep ! m2 output &&
+	test_grep ! br2 output
 '
 
 test_expect_success 'ending prompt input with EOF' '
 	git difftool -x cat branch </dev/null >output &&
-	! grep main output &&
-	! grep branch output &&
-	! grep m2 output &&
-	! grep br2 output
+	test_grep ! main output &&
+	test_grep ! branch output &&
+	test_grep ! m2 output &&
+	test_grep ! br2 output
 '
 
 test_expect_success 'difftool --tool-help' '
 	git difftool --tool-help >output &&
-	grep tool output
+	test_grep tool output
 '
 
 test_expect_success 'setup change in subdirectory' '
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 1b195bee59..d314393fce 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -1100,19 +1100,19 @@ test_expect_success 'grep -W with userdiff' '
 '
 
 test_expect_success ' includes preceding comment' '
-	grep "# Say hello" function-context-userdiff-actual
+	test_grep "# Say hello" function-context-userdiff-actual
 '
 
 test_expect_success ' includes function line' '
-	grep "=function hello" function-context-userdiff-actual
+	test_grep "=function hello" function-context-userdiff-actual
 '
 
 test_expect_success ' includes matching line' '
-	grep ":  echo" function-context-userdiff-actual
+	test_grep ":  echo" function-context-userdiff-actual
 '
 
 test_expect_success ' includes last line of the function' '
-	grep "} # hello" function-context-userdiff-actual
+	test_grep "} # hello" function-context-userdiff-actual
 '
 
 for threads in $(test_seq 0 10)
@@ -1136,16 +1136,16 @@ test_expect_success !PTHREADS,!FAIL_PREREQS \
 	git grep --threads=2 Hello hello_world 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 1 warnings &&
-	grep -F "no threads support, ignoring --threads" err &&
+	test_grep -F "no threads support, ignoring --threads" err &&
 	git -c grep.threads=2 grep Hello hello_world 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 1 warnings &&
-	grep -F "no threads support, ignoring grep.threads" err &&
+	test_grep -F "no threads support, ignoring grep.threads" err &&
 	git -c grep.threads=2 grep --threads=4 Hello hello_world 2>err &&
 	grep ^warning: err >warnings &&
 	test_line_count = 2 warnings &&
-	grep -F "no threads support, ignoring --threads" err &&
-	grep -F "no threads support, ignoring grep.threads" err &&
+	test_grep -F "no threads support, ignoring --threads" err &&
+	test_grep -F "no threads support, ignoring grep.threads" err &&
 	git -c grep.threads=0 grep --threads=0 Hello hello_world 2>err &&
 	test_line_count = 0 err
 '
@@ -1266,21 +1266,21 @@ test_expect_success 'no repository with path outside $cwd' '
 		export GIT_CEILING_DIRECTORIES &&
 		cd non/git &&
 		test_expect_code 128 git grep --no-index search .. 2>error &&
-		grep "is outside the directory tree" error
+		test_grep "is outside the directory tree" error
 	) &&
 	(
 		GIT_CEILING_DIRECTORIES="$(pwd)/non" &&
 		export GIT_CEILING_DIRECTORIES &&
 		cd non/git &&
 		test_expect_code 128 git grep --no-index search ../tig 2>error &&
-		grep "is outside the directory tree" error
+		test_grep "is outside the directory tree" error
 	) &&
 	(
 		GIT_CEILING_DIRECTORIES="$(pwd)/non" &&
 		export GIT_CEILING_DIRECTORIES &&
 		cd non/git &&
 		test_expect_code 128 git grep --no-index search ../non 2>error &&
-		grep "no such path in the working tree" error
+		test_grep "no such path in the working tree" error
 	)
 '
 
diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
index 167fe66150..e1cf53dc9e 100755
--- a/t/t7814-grep-recurse-submodules.sh
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -590,7 +590,7 @@ test_expect_success 'grep partially-cloned submodule' '
 			--recurse-submodules HEAD^ >actual &&
 		test_cmp expect actual &&
 		# Verify that we actually fetched data from the promisor remote:
-		grep \"category\":\"promisor\",\"key\":\"fetch_count\",\"value\":\"1\" trace2.log
+		test_grep \"category\":\"promisor\",\"key\":\"fetch_count\",\"value\":\"1\" trace2.log
 	)
 '
 
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index 9db4a76f67..cf170886c8 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -305,7 +305,7 @@ test_expect_success 'prefetch multiple remotes' '
 	test_cmp_rev refs/remotes/remote2/two refs/prefetch/remotes/remote2/two &&
 
 	git log --oneline --decorate --all >log &&
-	! grep "prefetch" log &&
+	test_grep ! "prefetch" log &&
 
 	test_when_finished git config --unset remote.remote1.skipFetchAll &&
 	git config remote.remote1.skipFetchAll true &&
@@ -395,15 +395,15 @@ test_expect_success 'maintenance.loose-objects.batchSize' '
 
 	GIT_PROGRESS_DELAY=0 \
 	git -C loose-batch maintenance run --no-quiet --task=loose-objects 2>err &&
-	grep "Enumerating objects: 50, done." err &&
+	test_grep "Enumerating objects: 50, done." err &&
 
 	GIT_PROGRESS_DELAY=0 \
 	git -C loose-batch maintenance run --no-quiet --task=loose-objects 2>err &&
-	grep "Enumerating objects: 50, done." err &&
+	test_grep "Enumerating objects: 50, done." err &&
 
 	GIT_PROGRESS_DELAY=0 \
 	git -C loose-batch maintenance run --no-quiet --task=loose-objects 2>err &&
-	grep "Enumerating objects: 2, done." err &&
+	test_grep "Enumerating objects: 2, done." err &&
 
 	GIT_PROGRESS_DELAY=0 \
 	git -C loose-batch maintenance run --no-quiet --task=loose-objects 2>err &&
@@ -1067,7 +1067,7 @@ test_expect_success 'register and unregister' '
 	test_when_finished git config --global --unset-all maintenance.repo &&
 
 	test_must_fail git maintenance unregister 2>err &&
-	grep "is not registered" err &&
+	test_grep "is not registered" err &&
 	git maintenance unregister --force &&
 
 	git config --global --add maintenance.repo /existing1 &&
@@ -1101,11 +1101,11 @@ test_expect_success 'register and unregister' '
 	test_cmp before actual &&
 
 	test_must_fail git maintenance unregister 2>err &&
-	grep "is not registered" err &&
+	test_grep "is not registered" err &&
 	git maintenance unregister --force &&
 
 	test_must_fail git maintenance unregister --config-file ./other 2>err &&
-	grep "is not registered" err &&
+	test_grep "is not registered" err &&
 	git maintenance unregister --config-file ./other --force
 '
 
@@ -1194,9 +1194,9 @@ test_expect_success 'start from empty cron table' '
 	# start registers the repo
 	git config --get --global --fixed-value maintenance.repo "$(pwd)" &&
 
-	grep "for-each-repo --keep-going --config=maintenance.repo maintenance run --schedule=daily" cron.txt &&
-	grep "for-each-repo --keep-going --config=maintenance.repo maintenance run --schedule=hourly" cron.txt &&
-	grep "for-each-repo --keep-going --config=maintenance.repo maintenance run --schedule=weekly" cron.txt
+	test_grep "for-each-repo --keep-going --config=maintenance.repo maintenance run --schedule=daily" cron.txt &&
+	test_grep "for-each-repo --keep-going --config=maintenance.repo maintenance run --schedule=hourly" cron.txt &&
+	test_grep "for-each-repo --keep-going --config=maintenance.repo maintenance run --schedule=weekly" cron.txt
 '
 
 test_expect_success 'stop from existing schedule' '
@@ -1213,7 +1213,7 @@ test_expect_success 'stop from existing schedule' '
 test_expect_success 'start preserves existing schedule' '
 	echo "Important information!" >cron.txt &&
 	GIT_TEST_MAINT_SCHEDULER="crontab:test-tool crontab cron.txt" git maintenance start --scheduler=crontab &&
-	grep "Important information!" cron.txt
+	test_grep "Important information!" cron.txt
 '
 
 test_expect_success 'magic markers are correct' '
@@ -1228,8 +1228,8 @@ test_expect_success 'magic markers are correct' '
 test_expect_success 'stop preserves surrounding schedule' '
 	echo "Crucial information!" >>cron.txt &&
 	GIT_TEST_MAINT_SCHEDULER="crontab:test-tool crontab cron.txt" git maintenance stop &&
-	grep "Important information!" cron.txt &&
-	grep "Crucial information!" cron.txt
+	test_grep "Important information!" cron.txt &&
+	test_grep "Crucial information!" cron.txt
 '
 
 test_expect_success 'start and stop macOS maintenance' '
@@ -1259,7 +1259,7 @@ test_expect_success 'start and stop macOS maintenance' '
 	do
 		PLIST="$pfx/Library/LaunchAgents/org.git-scm.git.$frequency.plist" &&
 		test_xmllint "$PLIST" &&
-		grep schedule=$frequency "$PLIST" &&
+		test_grep schedule=$frequency "$PLIST" &&
 		echo "bootout gui/[UID] $PLIST" >>expect &&
 		echo "bootstrap gui/[UID] $PLIST" >>expect || return 1
 	done &&
@@ -1316,7 +1316,7 @@ test_expect_success 'start and stop Windows maintenance' '
 
 	for frequency in hourly daily weekly
 	do
-		grep "/create /tn Git Maintenance ($frequency) /f /xml" args &&
+		test_grep "/create /tn Git Maintenance ($frequency) /f /xml" args &&
 		file=$(ls .git/schedule_${frequency}*.xml) &&
 		test_xmllint "$file" || return 1
 	done &&
@@ -1355,8 +1355,8 @@ test_expect_success 'start and stop Linux/systemd maintenance' '
 	test_systemd_analyze_verify "systemd/user/git-maintenance@daily.service" &&
 	test_systemd_analyze_verify "systemd/user/git-maintenance@weekly.service" &&
 
-	grep "core.askPass=true" "systemd/user/git-maintenance@.service" &&
-	grep "credential.interactive=false" "systemd/user/git-maintenance@.service" &&
+	test_grep "core.askPass=true" "systemd/user/git-maintenance@.service" &&
+	test_grep "credential.interactive=false" "systemd/user/git-maintenance@.service" &&
 
 	printf -- "--user enable --now git-maintenance@%s.timer\n" hourly daily weekly >expect &&
 	test_cmp expect args &&
diff --git a/t/t8008-blame-formats.sh b/t/t8008-blame-formats.sh
index c12a4196d6..016a837f14 100755
--- a/t/t8008-blame-formats.sh
+++ b/t/t8008-blame-formats.sh
@@ -103,7 +103,7 @@ test_expect_success '--porcelain detects first non-blank line as subject' '
 			"committer C <c@d.e> 123456789 +0000" |
 		git hash-object -w -t commit --stdin) &&
 		git blame --porcelain $commit -- single-file >output &&
-		grep "^summary oneline$" output
+		test_grep "^summary oneline$" output
 	)
 '
 
diff --git a/t/t8010-cat-file-filters.sh b/t/t8010-cat-file-filters.sh
index b3be2aa387..a4afb33c3e 100755
--- a/t/t8010-cat-file-filters.sh
+++ b/t/t8010-cat-file-filters.sh
@@ -49,7 +49,7 @@ test_expect_success '--path=<path> complains without --textconv/--filters' '
 	sha1=$(git rev-parse -q --verify HEAD:world.txt) &&
 	test_must_fail git cat-file --path=hello.txt blob $sha1 >actual 2>err &&
 	test_must_be_empty actual &&
-	grep "path.*needs.*filters" err
+	test_grep "path.*needs.*filters" err
 '
 
 test_expect_success '--textconv/--filters complain without path' '
diff --git a/t/t8012-blame-colors.sh b/t/t8012-blame-colors.sh
index 5562eba436..d2653b3c31 100755
--- a/t/t8012-blame-colors.sh
+++ b/t/t8012-blame-colors.sh
@@ -66,7 +66,7 @@ test_expect_success 'blame color by age: new code is different' '
 
 	grep "<CYAN>" <actual >colored &&
 	test_line_count = 1 colored &&
-	grep qfunc colored
+	test_grep qfunc colored
 '
 
 test_done
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index e7ab645a3d..e9d814a34a 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -348,9 +348,9 @@ test_expect_success $PREREQ 'Prompting works' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches \
 		2>errors &&
-		grep "^From: A U Thor <author@example.com>\$" msgtxt1 &&
-		grep "^To: to@example.com\$" msgtxt1 &&
-		grep "^In-Reply-To: <my-message-id@example.com>" msgtxt1
+		test_grep "^From: A U Thor <author@example.com>\$" msgtxt1 &&
+		test_grep "^To: to@example.com\$" msgtxt1 &&
+		test_grep "^In-Reply-To: <my-message-id@example.com>" msgtxt1
 '
 
 test_expect_success $PREREQ,AUTOIDENT 'implicit ident is allowed' '
@@ -403,7 +403,7 @@ test_expect_success $PREREQ 'tocmd works' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		tocmd.patch \
 		&&
-	grep "^To: tocmd@example.com" msgtxt1
+	test_grep "^To: tocmd@example.com" msgtxt1
 '
 
 test_expect_success $PREREQ 'cccmd works' '
@@ -417,7 +417,7 @@ test_expect_success $PREREQ 'cccmd works' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		cccmd.patch \
 		&&
-	grep "^	cccmd@example.com" msgtxt1
+	test_grep "^	cccmd@example.com" msgtxt1
 '
 
 test_expect_success $PREREQ 'headercmd works' '
@@ -431,7 +431,7 @@ test_expect_success $PREREQ 'headercmd works' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		headercmd.patch \
 		&&
-	grep "^X-Debbugs-CC: dummy@example.com" msgtxt1
+	test_grep "^X-Debbugs-CC: dummy@example.com" msgtxt1
 '
 
 test_expect_success $PREREQ '--no-header-cmd works' '
@@ -446,7 +446,7 @@ test_expect_success $PREREQ '--no-header-cmd works' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		headercmd.patch \
 		&&
-	! grep "^X-Debbugs-CC: dummy@example.com" msgtxt1
+	test_grep ! "^X-Debbugs-CC: dummy@example.com" msgtxt1
 '
 
 test_expect_success $PREREQ 'multiline fields are correctly unfolded' '
@@ -464,7 +464,7 @@ FoldedField: This is a tale
 		--header-cmd=./headercmd-multiline \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		headercmd.patch &&
-	grep "^FoldedField: This is a tale best told using multiple lines.$" msgtxt1
+	test_grep "^FoldedField: This is a tale best told using multiple lines.$" msgtxt1
 '
 
 # Blank lines in the middle of the output of a command are invalid.
@@ -521,7 +521,7 @@ test_expect_success $PREREQ 'Author From: in message body' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
 	sed "1,/^\$/d" <msgtxt1 >msgbody1 &&
-	grep "From: A <author@example.com>" msgbody1
+	test_grep "From: A <author@example.com>" msgbody1
 '
 
 test_expect_success $PREREQ 'Author From: not in message body' '
@@ -532,7 +532,7 @@ test_expect_success $PREREQ 'Author From: not in message body' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
 	sed "1,/^\$/d" <msgtxt1 >msgbody1 &&
-	! grep "From: A <author@example.com>" msgbody1
+	test_grep ! "From: A <author@example.com>" msgbody1
 '
 
 test_expect_success $PREREQ 'allow long lines with --no-validate' '
@@ -553,7 +553,7 @@ test_expect_success $PREREQ 'short lines with auto encoding are 8bit' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		--transfer-encoding=auto \
 		$patches &&
-	grep "Content-Transfer-Encoding: 8bit" msgtxt1
+	test_grep "Content-Transfer-Encoding: 8bit" msgtxt1
 '
 
 test_expect_success $PREREQ 'long lines with auto encoding are quoted-printable' '
@@ -565,7 +565,7 @@ test_expect_success $PREREQ 'long lines with auto encoding are quoted-printable'
 		--transfer-encoding=auto \
 		--no-validate \
 		longline.patch &&
-	grep "Content-Transfer-Encoding: quoted-printable" msgtxt1
+	test_grep "Content-Transfer-Encoding: quoted-printable" msgtxt1
 '
 
 test_expect_success $PREREQ 'carriage returns with auto encoding are quoted-printable' '
@@ -579,7 +579,7 @@ test_expect_success $PREREQ 'carriage returns with auto encoding are quoted-prin
 		--transfer-encoding=auto \
 		--no-validate \
 		cr.patch &&
-	grep "Content-Transfer-Encoding: quoted-printable" msgtxt1
+	test_grep "Content-Transfer-Encoding: quoted-printable" msgtxt1
 '
 
 for enc in auto quoted-printable base64
@@ -705,7 +705,7 @@ do
 			--smtp-server="$(pwd)/fake.sendmail" \
 			--transfer-encoding=$enc \
 			$patches &&
-		grep "Content-Transfer-Encoding: $enc" msgtxt1
+		test_grep "Content-Transfer-Encoding: $enc" msgtxt1
 	'
 done
 
@@ -718,7 +718,7 @@ test_expect_success $PREREQ 'Invalid In-Reply-To' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches \
 		2>errors &&
-	! grep "^In-Reply-To: < *>" msgtxt1
+	test_grep ! "^In-Reply-To: < *>" msgtxt1
 '
 
 test_expect_success $PREREQ 'Valid In-Reply-To when prompting' '
@@ -729,7 +729,7 @@ test_expect_success $PREREQ 'Valid In-Reply-To when prompting' '
 	) | GIT_SEND_EMAIL_NOTTY=1 git send-email \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches 2>errors &&
-	! grep "^In-Reply-To: < *>" msgtxt1
+	test_grep ! "^In-Reply-To: < *>" msgtxt1
 '
 
 test_expect_success $PREREQ 'In-Reply-To without --chain-reply-to' '
@@ -792,8 +792,8 @@ test_expect_success $PREREQ 'fake editor dies with error' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches 2>err &&
-	grep "I am about to error" err &&
-	grep "the editor exited uncleanly, aborting everything" err
+	test_grep "I am about to error" err &&
+	test_grep "the editor exited uncleanly, aborting everything" err
 '
 
 test_expect_success $PREREQ 'setup fake editor' '
@@ -814,11 +814,11 @@ test_expect_success $PREREQ '--compose works' '
 '
 
 test_expect_success $PREREQ 'first message is compose text' '
-	grep "^fake edit" msgtxt1
+	test_grep "^fake edit" msgtxt1
 '
 
 test_expect_success $PREREQ 'second message is patch' '
-	grep "Subject:.*Second" msgtxt2
+	test_grep "Subject:.*Second" msgtxt2
 '
 
 test_expect_success $PREREQ 'setup expect' "
@@ -1237,8 +1237,8 @@ test_expect_success $PREREQ '--compose adds MIME for utf8 body' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
-	grep "^utf8 body" msgtxt1 &&
-	grep "^Content-Type: text/plain; charset=UTF-8" msgtxt1
+	test_grep "^utf8 body" msgtxt1 &&
+	test_grep "^Content-Type: text/plain; charset=UTF-8" msgtxt1
 '
 
 test_expect_success $PREREQ '--compose respects user mime type' '
@@ -1260,9 +1260,9 @@ test_expect_success $PREREQ '--compose respects user mime type' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
-	grep "^utf8 body" msgtxt1 &&
-	grep "^Content-Type: text/plain; charset=iso-8859-1" msgtxt1 &&
-	! grep "^Content-Type: text/plain; charset=UTF-8" msgtxt1
+	test_grep "^utf8 body" msgtxt1 &&
+	test_grep "^Content-Type: text/plain; charset=iso-8859-1" msgtxt1 &&
+	test_grep ! "^Content-Type: text/plain; charset=UTF-8" msgtxt1
 '
 
 test_expect_success $PREREQ '--compose adds MIME for utf8 subject' '
@@ -1274,8 +1274,8 @@ test_expect_success $PREREQ '--compose adds MIME for utf8 subject' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
-	grep "^fake edit" msgtxt1 &&
-	grep "^Subject: =?UTF-8?q?utf8-s=C3=BCbj=C3=ABct?=" msgtxt1
+	test_grep "^fake edit" msgtxt1 &&
+	test_grep "^Subject: =?UTF-8?q?utf8-s=C3=BCbj=C3=ABct?=" msgtxt1
 '
 
 test_expect_success $PREREQ 'utf8 author is correctly passed on' '
@@ -1288,7 +1288,7 @@ test_expect_success $PREREQ 'utf8 author is correctly passed on' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		funny_name.patch &&
-	grep "^From: Füñný Nâmé <odd_?=mail@example.com>" msgtxt1
+	test_grep "^From: Füñný Nâmé <odd_?=mail@example.com>" msgtxt1
 '
 
 test_expect_success $PREREQ 'utf8 sender is not duplicated' '
@@ -1361,8 +1361,8 @@ test_expect_success $PREREQ 'sendemail.composeencoding works' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
-	grep "^utf8 body" msgtxt1 &&
-	grep "^Content-Type: text/plain; charset=iso-8859-1" msgtxt1
+	test_grep "^utf8 body" msgtxt1 &&
+	test_grep "^Content-Type: text/plain; charset=iso-8859-1" msgtxt1
 '
 
 test_expect_success $PREREQ '--compose-encoding works' '
@@ -1378,8 +1378,8 @@ test_expect_success $PREREQ '--compose-encoding works' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
-	grep "^utf8 body" msgtxt1 &&
-	grep "^Content-Type: text/plain; charset=iso-8859-1" msgtxt1
+	test_grep "^utf8 body" msgtxt1 &&
+	test_grep "^Content-Type: text/plain; charset=iso-8859-1" msgtxt1
 '
 
 test_expect_success $PREREQ '--compose-encoding overrides sendemail.composeencoding' '
@@ -1396,8 +1396,8 @@ test_expect_success $PREREQ '--compose-encoding overrides sendemail.composeencod
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
-	grep "^utf8 body" msgtxt1 &&
-	grep "^Content-Type: text/plain; charset=iso-8859-2" msgtxt1
+	test_grep "^utf8 body" msgtxt1 &&
+	test_grep "^Content-Type: text/plain; charset=iso-8859-2" msgtxt1
 '
 
 test_expect_success $PREREQ '--compose-encoding adds correct MIME for subject' '
@@ -1410,8 +1410,8 @@ test_expect_success $PREREQ '--compose-encoding adds correct MIME for subject' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches &&
-	grep "^fake edit" msgtxt1 &&
-	grep "^Subject: =?iso-8859-2?q?utf8-s=C3=BCbj=C3=ABct?=" msgtxt1
+	test_grep "^fake edit" msgtxt1 &&
+	test_grep "^Subject: =?iso-8859-2?q?utf8-s=C3=BCbj=C3=ABct?=" msgtxt1
 '
 
 test_expect_success $PREREQ 'detects ambiguous reference/file conflict' '
@@ -1419,7 +1419,7 @@ test_expect_success $PREREQ 'detects ambiguous reference/file conflict' '
 	git add main &&
 	git commit -m"add main" &&
 	test_must_fail git send-email --dry-run main 2>errors &&
-	grep disambiguate errors
+	test_grep disambiguate errors
 '
 
 test_expect_success $PREREQ 'feed two files' '
@@ -1443,7 +1443,7 @@ test_expect_success $PREREQ 'in-reply-to but no threading' '
 		--in-reply-to="<in-reply-id@example.com>" \
 		--no-thread \
 		$patches >out &&
-	grep "In-Reply-To: <in-reply-id@example.com>" out
+	test_grep "In-Reply-To: <in-reply-id@example.com>" out
 '
 
 test_expect_success $PREREQ 'no in-reply-to and no threading' '
@@ -1453,7 +1453,7 @@ test_expect_success $PREREQ 'no in-reply-to and no threading' '
 		--to=nobody@example.com \
 		--no-thread \
 		$patches >stdout &&
-	! grep "In-Reply-To: " stdout
+	test_grep ! "In-Reply-To: " stdout
 '
 
 test_expect_success $PREREQ 'threading but no chain-reply-to' '
@@ -1464,7 +1464,7 @@ test_expect_success $PREREQ 'threading but no chain-reply-to' '
 		--thread \
 		--no-chain-reply-to \
 		$patches $patches >stdout &&
-	grep "In-Reply-To: " stdout
+	test_grep "In-Reply-To: " stdout
 '
 
 test_expect_success $PREREQ 'override in-reply-to if no threading' '
@@ -1475,7 +1475,7 @@ test_expect_success $PREREQ 'override in-reply-to if no threading' '
 		--no-thread \
 		--in-reply-to="override" \
 		$threaded_patches >stdout &&
-	grep "In-Reply-To: <override>" stdout
+	test_grep "In-Reply-To: <override>" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.to works' '
@@ -1484,7 +1484,7 @@ test_expect_success $PREREQ 'sendemail.to works' '
 		--dry-run \
 		--from="Example <nobody@example.com>" \
 		$patches >stdout &&
-	grep "To: Somebody <somebody@ex.com>" stdout
+	test_grep "To: Somebody <somebody@ex.com>" stdout
 '
 
 test_expect_success $PREREQ 'setup sendemail.identity' '
@@ -1498,7 +1498,7 @@ test_expect_success $PREREQ 'sendemail.identity: reads the correct identity conf
 		--dry-run \
 		--from="nobody@example.com" \
 		$patches >stdout &&
-	grep "To: cloud@example.com" stdout
+	test_grep "To: cloud@example.com" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.identity: identity overrides sendemail.identity' '
@@ -1507,7 +1507,7 @@ test_expect_success $PREREQ 'sendemail.identity: identity overrides sendemail.id
 		--dry-run \
 		--from="nobody@example.com" \
 		$patches >stdout &&
-	grep "To: isp@example.com" stdout
+	test_grep "To: isp@example.com" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.identity: --no-identity clears previous identity' '
@@ -1516,7 +1516,7 @@ test_expect_success $PREREQ 'sendemail.identity: --no-identity clears previous i
 		--dry-run \
 		--from="nobody@example.com" \
 		$patches >stdout &&
-	grep "To: default@example.com" stdout
+	test_grep "To: default@example.com" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.identity: bool identity variable existence overrides' '
@@ -1527,8 +1527,8 @@ test_expect_success $PREREQ 'sendemail.identity: bool identity variable existenc
 		--dry-run \
 		--from="nobody@example.com" \
 		$patches >stdout &&
-	grep "To: cloud@example.com" stdout &&
-	! grep "X-Mailer" stdout
+	test_grep "To: cloud@example.com" stdout &&
+	test_grep ! "X-Mailer" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.identity: bool variable fallback' '
@@ -1538,8 +1538,8 @@ test_expect_success $PREREQ 'sendemail.identity: bool variable fallback' '
 		--dry-run \
 		--from="nobody@example.com" \
 		$patches >stdout &&
-	grep "To: cloud@example.com" stdout &&
-	! grep "X-Mailer" stdout
+	test_grep "To: cloud@example.com" stdout &&
+	test_grep ! "X-Mailer" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.identity: bool variable without a value' '
@@ -1548,8 +1548,8 @@ test_expect_success $PREREQ 'sendemail.identity: bool variable without a value'
 		--dry-run \
 		--from="nobody@example.com" \
 		$patches >stdout &&
-	grep "To: default@example.com" stdout &&
-	grep "X-Mailer" stdout
+	test_grep "To: default@example.com" stdout &&
+	test_grep "X-Mailer" stdout
 '
 
 test_expect_success $PREREQ '--no-to overrides sendemail.to' '
@@ -1559,8 +1559,8 @@ test_expect_success $PREREQ '--no-to overrides sendemail.to' '
 		--no-to \
 		--to=nobody@example.com \
 		$patches >stdout &&
-	grep "To: nobody@example.com" stdout &&
-	! grep "To: Somebody <somebody@ex.com>" stdout
+	test_grep "To: nobody@example.com" stdout &&
+	test_grep ! "To: Somebody <somebody@ex.com>" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.cc works' '
@@ -1570,7 +1570,7 @@ test_expect_success $PREREQ 'sendemail.cc works' '
 		--from="Example <nobody@example.com>" \
 		--to=nobody@example.com \
 		$patches >stdout &&
-	grep "Cc: Somebody <somebody@ex.com>" stdout
+	test_grep "Cc: Somebody <somebody@ex.com>" stdout
 '
 
 test_expect_success $PREREQ '--no-cc overrides sendemail.cc' '
@@ -1581,8 +1581,8 @@ test_expect_success $PREREQ '--no-cc overrides sendemail.cc' '
 		--cc=bodies@example.com \
 		--to=nobody@example.com \
 		$patches >stdout &&
-	grep "Cc: bodies@example.com" stdout &&
-	! grep "Cc: Somebody <somebody@ex.com>" stdout
+	test_grep "Cc: bodies@example.com" stdout &&
+	test_grep ! "Cc: Somebody <somebody@ex.com>" stdout
 '
 
 test_expect_success $PREREQ 'sendemail.bcc works' '
@@ -1593,7 +1593,7 @@ test_expect_success $PREREQ 'sendemail.bcc works' '
 		--to=nobody@example.com \
 		--smtp-server relay.example.com \
 		$patches >stdout &&
-	grep "RCPT TO:<other@ex.com>" stdout
+	test_grep "RCPT TO:<other@ex.com>" stdout
 '
 
 test_expect_success $PREREQ '--no-bcc overrides sendemail.bcc' '
@@ -1605,8 +1605,8 @@ test_expect_success $PREREQ '--no-bcc overrides sendemail.bcc' '
 		--to=nobody@example.com \
 		--smtp-server relay.example.com \
 		$patches >stdout &&
-	grep "RCPT TO:<bodies@example.com>" stdout &&
-	! grep "RCPT TO:<other@ex.com>" stdout
+	test_grep "RCPT TO:<bodies@example.com>" stdout &&
+	test_grep ! "RCPT TO:<other@ex.com>" stdout
 '
 
 test_expect_success $PREREQ 'patches To headers are used by default' '
@@ -1617,7 +1617,7 @@ test_expect_success $PREREQ 'patches To headers are used by default' '
 		--from="Example <nobody@example.com>" \
 		--smtp-server relay.example.com \
 		$patch >stdout &&
-	grep "RCPT TO:<bodies@example.com>" stdout
+	test_grep "RCPT TO:<bodies@example.com>" stdout
 '
 
 test_expect_success $PREREQ 'patches To headers are appended to' '
@@ -1629,8 +1629,8 @@ test_expect_success $PREREQ 'patches To headers are appended to' '
 		--to=nobody@example.com \
 		--smtp-server relay.example.com \
 		$patch >stdout &&
-	grep "RCPT TO:<bodies@example.com>" stdout &&
-	grep "RCPT TO:<nobody@example.com>" stdout
+	test_grep "RCPT TO:<bodies@example.com>" stdout &&
+	test_grep "RCPT TO:<nobody@example.com>" stdout
 '
 
 test_expect_success $PREREQ 'To headers from files reset each patch' '
@@ -1691,9 +1691,9 @@ test_expect_success $PREREQ 'asks about and fixes 8bit encodings' '
 	git send-email --from=author@example.com --to=nobody@example.com \
 			--smtp-server="$(pwd)/fake.sendmail" \
 			email-using-8bit >stdout &&
-	grep "do not declare a Content-Transfer-Encoding" stdout &&
-	grep email-using-8bit stdout &&
-	grep "Declare which 8bit encoding to use" stdout &&
+	test_grep "do not declare a Content-Transfer-Encoding" stdout &&
+	test_grep email-using-8bit stdout &&
+	test_grep "Declare which 8bit encoding to use" stdout &&
 	grep -E "Content|MIME" msgtxt1 >actual &&
 	test_cmp content-type-decl actual
 '
@@ -1790,7 +1790,7 @@ test_expect_success $PREREQ '--transfer-encoding overrides sendemail.transferEnc
 		--smtp-server="$(pwd)/fake.sendmail" \
 		email-using-8bit \
 		2>errors >out &&
-	grep "cannot send message as 7bit" errors &&
+	test_grep "cannot send message as 7bit" errors &&
 	test -z "$(ls msgtxt*)"
 '
 
@@ -1801,7 +1801,7 @@ test_expect_success $PREREQ 'sendemail.transferEncoding via config' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		email-using-8bit \
 		2>errors >out &&
-	grep "cannot send message as 7bit" errors &&
+	test_grep "cannot send message as 7bit" errors &&
 	test -z "$(ls msgtxt*)"
 '
 
@@ -1812,7 +1812,7 @@ test_expect_success $PREREQ 'sendemail.transferEncoding via cli' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		email-using-8bit \
 		2>errors >out &&
-	grep "cannot send message as 7bit" errors &&
+	test_grep "cannot send message as 7bit" errors &&
 	test -z "$(ls msgtxt*)"
 '
 
@@ -1939,7 +1939,7 @@ test_expect_success $PREREQ 'refusing to send cover letter template' '
 		outdir/0000-*.patch \
 		outdir/0001-*.patch \
 		2>errors >out &&
-	grep "SUBJECT HERE" errors &&
+	test_grep "SUBJECT HERE" errors &&
 	test -z "$(ls msgtxt*)"
 '
 
@@ -1956,7 +1956,7 @@ test_expect_success $PREREQ '--force sends cover letter template anyway' '
 		outdir/0000-*.patch \
 		outdir/0001-*.patch \
 		2>errors >out &&
-	! grep "SUBJECT HERE" errors &&
+	test_grep ! "SUBJECT HERE" errors &&
 	test -n "$(ls msgtxt*)"
 '
 
@@ -2016,8 +2016,8 @@ test_expect_success $PREREQ 'escaped quotes in sendemail.aliasfiletype=mutt' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		outdir/0001-*.patch \
 		2>errors >out &&
-	grep "^!somebody@example\.org!$" commandline1 &&
-	grep -F "To: \"Dot U. Sir\" <somebody@example.org>" out
+	test_grep "^!somebody@example\.org!$" commandline1 &&
+	test_grep -F "To: \"Dot U. Sir\" <somebody@example.org>" out
 '
 
 test_expect_success $PREREQ 'sendemail.aliasfiletype=mailrc' '
@@ -2031,7 +2031,7 @@ test_expect_success $PREREQ 'sendemail.aliasfiletype=mailrc' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		outdir/0001-*.patch \
 		2>errors >out &&
-	grep "^!somebody@example\.org!$" commandline1
+	test_grep "^!somebody@example\.org!$" commandline1
 '
 
 test_expect_success $PREREQ 'sendemail.aliasesfile=~/.mailrc' '
@@ -2045,7 +2045,7 @@ test_expect_success $PREREQ 'sendemail.aliasesfile=~/.mailrc' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		outdir/0001-*.patch \
 		2>errors >out &&
-	grep "^!someone@example\.org!$" commandline1
+	test_grep "^!someone@example\.org!$" commandline1
 '
 
 test_dump_aliases () {
@@ -2264,7 +2264,7 @@ test_sendmail_aliases () {
 			2>errors >out &&
 		for i in $expect
 		do
-			grep "^!$i!$" commandline1 || return 1
+			test_grep "^!$i!$" commandline1 || return 1
 		done
 	'
 }
@@ -2328,7 +2328,7 @@ test_expect_success $PREREQ 'alias support in To header' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		aliased.patch \
 		2>errors >out &&
-	grep "^!someone@example\.org!$" commandline1
+	test_grep "^!someone@example\.org!$" commandline1
 '
 
 test_expect_success $PREREQ 'alias support in Cc header' '
@@ -2342,7 +2342,7 @@ test_expect_success $PREREQ 'alias support in Cc header' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		aliased.patch \
 		2>errors >out &&
-	grep "^!someone@example\.org!$" commandline1
+	test_grep "^!someone@example\.org!$" commandline1
 '
 
 test_expect_success $PREREQ 'tocmd works with aliases' '
@@ -2358,7 +2358,7 @@ test_expect_success $PREREQ 'tocmd works with aliases' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		tocmd.patch \
 		2>errors >out &&
-	grep "^!someone@example\.org!$" commandline1
+	test_grep "^!someone@example\.org!$" commandline1
 '
 
 test_expect_success $PREREQ 'cccmd works with aliases' '
@@ -2374,7 +2374,7 @@ test_expect_success $PREREQ 'cccmd works with aliases' '
 		--smtp-server="$(pwd)/fake.sendmail" \
 		cccmd.patch \
 		2>errors >out &&
-	grep "^!someone@example\.org!$" commandline1
+	test_grep "^!someone@example\.org!$" commandline1
 '
 
 do_xmailer_test () {
@@ -2511,7 +2511,7 @@ test_expect_success $PREREQ 'mailmap support with --to' '
 		--mailmap \
 		a.patch \
 		2>errors >out &&
-	grep "^!someone@example\.com!$" commandline1
+	test_grep "^!someone@example\.com!$" commandline1
 '
 
 test_expect_success $PREREQ 'sendemail.mailmap configuration' '
@@ -2528,7 +2528,7 @@ test_expect_success $PREREQ 'sendemail.mailmap configuration' '
 		--to=someone@example.org \
 		a.patch \
 		2>errors >out &&
-	grep "^!someone@example\.com!$" commandline1
+	test_grep "^!someone@example\.com!$" commandline1
 '
 
 test_expect_success $PREREQ 'sendemail.mailmap.file configuration' '
@@ -2545,7 +2545,7 @@ test_expect_success $PREREQ 'sendemail.mailmap.file configuration' '
 		--to=someone@example.org \
 		a.patch \
 		2>errors >out &&
-	grep "^!someone@example\.com!$" commandline1
+	test_grep "^!someone@example\.com!$" commandline1
 '
 
 test_expect_success $PREREQ 'sendemail.mailmap identity overrides configuration' '
@@ -2564,7 +2564,7 @@ test_expect_success $PREREQ 'sendemail.mailmap identity overrides configuration'
 		--to=someone@example.org \
 		a.patch \
 		2>errors >out &&
-	grep "^!someone@example\.com!$" commandline1
+	test_grep "^!someone@example\.com!$" commandline1
 '
 
 test_expect_success $PREREQ '--no-mailmap overrides configuration' '
@@ -2584,7 +2584,7 @@ test_expect_success $PREREQ '--no-mailmap overrides configuration' '
 		--no-mailmap \
 		a.patch \
 		2>errors >out &&
-	grep "^!someone@example\.org!$" commandline1
+	test_grep "^!someone@example\.org!$" commandline1
 '
 
 test_expect_success $PREREQ 'mailmap support in To header' '
@@ -2600,7 +2600,7 @@ test_expect_success $PREREQ 'mailmap support in To header' '
 		--mailmap \
 		a.patch \
 		2>errors >out &&
-	grep "^!someone@example\.com!$" commandline1
+	test_grep "^!someone@example\.com!$" commandline1
 '
 
 test_expect_success $PREREQ 'mailmap support in Cc header' '
@@ -2616,7 +2616,7 @@ test_expect_success $PREREQ 'mailmap support in Cc header' '
 		--mailmap \
 		a.patch \
 		2>errors >out &&
-	grep "^!someone@example\.com!$" commandline1
+	test_grep "^!someone@example\.com!$" commandline1
 '
 
 test_expect_success $PREREQ 'test using command name with --sendmail-cmd' '
@@ -2676,9 +2676,9 @@ test_expect_success $PREREQ 'patch reply headers correct with --no-thread' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		has-reply.patch no-reply.patch &&
-	grep "In-Reply-To: <replied.to@example.com>" msgtxt1 &&
-	grep "References: <replied.to@example.com>" msgtxt1 &&
-	! grep replied.to@example.com msgtxt2
+	test_grep "In-Reply-To: <replied.to@example.com>" msgtxt1 &&
+	test_grep "References: <replied.to@example.com>" msgtxt1 &&
+	test_grep ! replied.to@example.com msgtxt2
 '
 
 test_expect_success $PREREQ 'cmdline in-reply-to used with --no-thread' '
@@ -2689,10 +2689,10 @@ test_expect_success $PREREQ 'cmdline in-reply-to used with --no-thread' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		has-reply.patch no-reply.patch &&
-	grep "In-Reply-To: <cmdline.reply@example.com>" msgtxt1 &&
-	grep "References: <cmdline.reply@example.com>" msgtxt1 &&
-	grep "In-Reply-To: <cmdline.reply@example.com>" msgtxt2 &&
-	grep "References: <cmdline.reply@example.com>" msgtxt2
+	test_grep "In-Reply-To: <cmdline.reply@example.com>" msgtxt1 &&
+	test_grep "References: <cmdline.reply@example.com>" msgtxt1 &&
+	test_grep "In-Reply-To: <cmdline.reply@example.com>" msgtxt2 &&
+	test_grep "References: <cmdline.reply@example.com>" msgtxt2
 '
 
 test_expect_success $PREREQ 'invoke hook' '
@@ -2775,7 +2775,7 @@ test_expect_success $PREREQ 'test that send-email works outside a repo' '
 test_expect_success $PREREQ 'send-email relays -v 3 to format-patch' '
 	test_when_finished "rm -f out" &&
 	git send-email --dry-run -v 3 -1 >out &&
-	grep "PATCH v3" out
+	test_grep "PATCH v3" out
 '
 
 test_expect_success $PREREQ 'test that sendmail config is rejected' '
@@ -2819,7 +2819,7 @@ test_expect_success $PREREQ '--compose handles lowercase headers' '
 		--to=nobody@example.com \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		HEAD^ &&
-	grep "From: edited-from@example.com" msgtxt1
+	test_grep "From: edited-from@example.com" msgtxt1
 '
 
 test_expect_success $PREREQ '--compose handles to headers' '
diff --git a/t/t9003-help-autocorrect.sh b/t/t9003-help-autocorrect.sh
index 8da318d2b5..87b438fcac 100755
--- a/t/t9003-help-autocorrect.sh
+++ b/t/t9003-help-autocorrect.sh
@@ -34,10 +34,10 @@ do
 		git config help.autocorrect $show &&
 
 		test_must_fail git lfg 2>actual &&
-		grep "^	lgf" actual &&
+		test_grep "^	lgf" actual &&
 
 		test_must_fail git distimdist 2>actual &&
-		grep "^	distimdistim" actual
+		test_grep "^	distimdistim" actual
 	'
 done
 
@@ -60,7 +60,7 @@ test_expect_success 'autocorrect can be declined altogether' '
 	git config help.autocorrect never &&
 
 	test_must_fail git lfg 2>actual &&
-	grep "is not a git command" actual &&
+	test_grep "is not a git command" actual &&
 	test_line_count = 1 actual
 '
 
diff --git a/t/t9106-git-svn-commit-diff-clobber.sh b/t/t9106-git-svn-commit-diff-clobber.sh
index bca496c40e..376100fd7a 100755
--- a/t/t9106-git-svn-commit-diff-clobber.sh
+++ b/t/t9106-git-svn-commit-diff-clobber.sh
@@ -94,7 +94,7 @@ test_expect_success 'multiple dcommit from git svn will not clobber svn' "
 
 test_expect_success 'check that rebase really failed' '
 	git status >output &&
-	grep currently.rebasing output
+	test_grep currently.rebasing output
 '
 
 test_expect_success 'resolve, continue the rebase and dcommit' "
diff --git a/t/t9107-git-svn-migrate.sh b/t/t9107-git-svn-migrate.sh
index aa908bbc2f..6d7d2aa491 100755
--- a/t/t9107-git-svn-migrate.sh
+++ b/t/t9107-git-svn-migrate.sh
@@ -46,7 +46,7 @@ test_expect_success 'initialize old-style (v0) git svn layout' '
 test_expect_success 'initialize a multi-repository repo' '
 	git svn init "$svnrepo" -T trunk -t tags -b branches &&
 	git config --get-all svn-remote.svn.fetch > fetch.out &&
-	grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
+	test_grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
 	test -n "$(git config --get svn-remote.svn.branches \
 		    "^branches/\*:refs/remotes/origin/\*$")" &&
 	test -n "$(git config --get svn-remote.svn.tags \
@@ -63,13 +63,13 @@ test_expect_success 'initialize a multi-repository repo' '
 			$i:refs/remotes/origin/$i || return 1
 	done &&
 	git config --get-all svn-remote.svn.fetch > fetch.out &&
-	grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
-	grep "^branches/a:refs/remotes/origin/a$" fetch.out &&
-	grep "^branches/b:refs/remotes/origin/b$" fetch.out &&
-	grep "^tags/0\.1:refs/remotes/origin/tags/0\.1$" fetch.out &&
-	grep "^tags/0\.2:refs/remotes/origin/tags/0\.2$" fetch.out &&
-	grep "^tags/0\.3:refs/remotes/origin/tags/0\.3$" fetch.out &&
-	grep "^:refs/remotes/git-svn" fetch.out
+	test_grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
+	test_grep "^branches/a:refs/remotes/origin/a$" fetch.out &&
+	test_grep "^branches/b:refs/remotes/origin/b$" fetch.out &&
+	test_grep "^tags/0\.1:refs/remotes/origin/tags/0\.1$" fetch.out &&
+	test_grep "^tags/0\.2:refs/remotes/origin/tags/0\.2$" fetch.out &&
+	test_grep "^tags/0\.3:refs/remotes/origin/tags/0\.3$" fetch.out &&
+	test_grep "^:refs/remotes/git-svn" fetch.out
 	'
 
 # refs should all be different, but the trees should all be the same:
@@ -109,13 +109,13 @@ test_expect_success 'migrate --minimize on old inited layout' '
 	git svn migrate --minimize &&
 	test -z "$(git config -l | grep "^svn-remote\.git-svn\.")" &&
 	git config --get-all svn-remote.svn.fetch > fetch.out &&
-	grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
-	grep "^branches/a:refs/remotes/origin/a$" fetch.out &&
-	grep "^branches/b:refs/remotes/origin/b$" fetch.out &&
-	grep "^tags/0\.1:refs/remotes/origin/tags/0\.1$" fetch.out &&
-	grep "^tags/0\.2:refs/remotes/origin/tags/0\.2$" fetch.out &&
-	grep "^tags/0\.3:refs/remotes/origin/tags/0\.3$" fetch.out &&
-	grep "^:refs/remotes/git-svn" fetch.out
+	test_grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
+	test_grep "^branches/a:refs/remotes/origin/a$" fetch.out &&
+	test_grep "^branches/b:refs/remotes/origin/b$" fetch.out &&
+	test_grep "^tags/0\.1:refs/remotes/origin/tags/0\.1$" fetch.out &&
+	test_grep "^tags/0\.2:refs/remotes/origin/tags/0\.2$" fetch.out &&
+	test_grep "^tags/0\.3:refs/remotes/origin/tags/0\.3$" fetch.out &&
+	test_grep "^:refs/remotes/git-svn" fetch.out
 	'
 
 test_expect_success  ".rev_db auto-converted to .rev_map.UUID" '
diff --git a/t/t9110-git-svn-use-svm-props.sh b/t/t9110-git-svn-use-svm-props.sh
index ad37d980c9..9dc4a31a44 100755
--- a/t/t9110-git-svn-use-svm-props.sh
+++ b/t/t9110-git-svn-use-svm-props.sh
@@ -22,36 +22,36 @@ uuid=161ce429-a9dd-4828-af4a-52023f968c89
 bar_url=http://mayonaise/svnrepo/bar
 test_expect_success 'verify metadata for /bar' "
 	git cat-file commit refs/remotes/bar >actual &&
-	grep '^git-svn-id: $bar_url@12 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@12 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~1 >actual &&
-	grep '^git-svn-id: $bar_url@11 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@11 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~2 >actual &&
-	grep '^git-svn-id: $bar_url@10 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@10 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~3 >actual &&
-	grep '^git-svn-id: $bar_url@9 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@9 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~4 >actual &&
-	grep '^git-svn-id: $bar_url@6 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@6 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~5 >actual &&
-	grep '^git-svn-id: $bar_url@1 $uuid$' actual
+	test_grep '^git-svn-id: $bar_url@1 $uuid$' actual
 	"
 
 e_url=http://mayonaise/svnrepo/dir/a/b/c/d/e
 test_expect_success 'verify metadata for /dir/a/b/c/d/e' "
 	git cat-file commit refs/remotes/e >actual &&
-	grep '^git-svn-id: $e_url@1 $uuid$' actual
+	test_grep '^git-svn-id: $e_url@1 $uuid$' actual
 	"
 
 dir_url=http://mayonaise/svnrepo/dir
 test_expect_success 'verify metadata for /dir' "
 	git cat-file commit refs/remotes/dir >actual &&
-	grep '^git-svn-id: $dir_url@2 $uuid$' actual &&
+	test_grep '^git-svn-id: $dir_url@2 $uuid$' actual &&
 	git cat-file commit refs/remotes/dir~1 >actual &&
-	grep '^git-svn-id: $dir_url@1 $uuid$' actual
+	test_grep '^git-svn-id: $dir_url@1 $uuid$' actual
 	"
 
 test_expect_success 'find commit based on SVN revision number' "
 	git svn find-rev r12 >actual &&
-	grep $(git rev-parse HEAD) actual
+	test_grep $(git rev-parse HEAD) actual
         "
 
 test_expect_success 'empty rebase' "
diff --git a/t/t9111-git-svn-use-svnsync-props.sh b/t/t9111-git-svn-use-svnsync-props.sh
index 6c93073551..e45d81bfc4 100755
--- a/t/t9111-git-svn-use-svnsync-props.sh
+++ b/t/t9111-git-svn-use-svnsync-props.sh
@@ -21,31 +21,31 @@ uuid=161ce429-a9dd-4828-af4a-52023f968c89
 bar_url=http://mayonaise/svnrepo/bar
 test_expect_success 'verify metadata for /bar' "
 	git cat-file commit refs/remotes/bar >actual &&
-	grep '^git-svn-id: $bar_url@12 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@12 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~1 >actual &&
-	grep '^git-svn-id: $bar_url@11 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@11 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~2 >actual &&
-	grep '^git-svn-id: $bar_url@10 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@10 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~3 >actual &&
-	grep '^git-svn-id: $bar_url@9 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@9 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~4 >actual &&
-	grep '^git-svn-id: $bar_url@6 $uuid$' actual &&
+	test_grep '^git-svn-id: $bar_url@6 $uuid$' actual &&
 	git cat-file commit refs/remotes/bar~5 >actual &&
-	grep '^git-svn-id: $bar_url@1 $uuid$' actual
+	test_grep '^git-svn-id: $bar_url@1 $uuid$' actual
 	"
 
 e_url=http://mayonaise/svnrepo/dir/a/b/c/d/e
 test_expect_success 'verify metadata for /dir/a/b/c/d/e' "
 	git cat-file commit refs/remotes/e >actual &&
-	grep '^git-svn-id: $e_url@1 $uuid$' actual
+	test_grep '^git-svn-id: $e_url@1 $uuid$' actual
 	"
 
 dir_url=http://mayonaise/svnrepo/dir
 test_expect_success 'verify metadata for /dir' "
 	git cat-file commit refs/remotes/dir >actual &&
-	grep '^git-svn-id: $dir_url@2 $uuid$' actual &&
+	test_grep '^git-svn-id: $dir_url@2 $uuid$' actual &&
 	git cat-file commit refs/remotes/dir~1 >actual &&
-	grep '^git-svn-id: $dir_url@1 $uuid$' actual
+	test_grep '^git-svn-id: $dir_url@1 $uuid$' actual
 	"
 
 test_done
diff --git a/t/t9114-git-svn-dcommit-merge.sh b/t/t9114-git-svn-dcommit-merge.sh
index e06538b1c8..2240b58d4d 100755
--- a/t/t9114-git-svn-dcommit-merge.sh
+++ b/t/t9114-git-svn-dcommit-merge.sh
@@ -69,7 +69,7 @@ test_expect_success 'verify pre-merge ancestry' "
 	test x\$(git rev-parse --verify refs/heads/svn^2) = \
 	     x\$(git rev-parse --verify refs/heads/merge) &&
 	git cat-file commit refs/heads/svn^ >actual &&
-	grep '^friend$' actual
+	test_grep '^friend$' actual
 	"
 
 test_expect_success 'git svn dcommit merges' "
@@ -84,12 +84,12 @@ test_expect_success 'verify post-merge ancestry' "
 	test x\$(git rev-parse --verify refs/heads/svn^2) = \
 	     x\$(git rev-parse --verify refs/heads/merge) &&
 	git cat-file commit refs/heads/svn^ >actual &&
-	grep '^friend$' actual
+	test_grep '^friend$' actual
 	"
 
 test_expect_success 'verify merge commit message' "
 	git rev-list --pretty=raw -1 refs/heads/svn >actual &&
-	grep \"    Merge branch 'merge' into svn\" actual
+	test_grep \"    Merge branch 'merge' into svn\" actual
 	"
 
 test_done
diff --git a/t/t9116-git-svn-log.sh b/t/t9116-git-svn-log.sh
index d74d7b2de6..b2e1248651 100755
--- a/t/t9116-git-svn-log.sh
+++ b/t/t9116-git-svn-log.sh
@@ -45,17 +45,17 @@ test_expect_success 'setup repository and import' '
 test_expect_success 'run log' "
 	git reset --hard origin/a &&
 	git svn log -r2 origin/trunk >out &&
-	grep ^r2 out &&
+	test_grep ^r2 out &&
 	git svn log -r4 origin/trunk >out &&
-	grep ^r4 out &&
+	test_grep ^r4 out &&
 	git svn log -r3 >out &&
-	grep ^r3 out
+	test_grep ^r3 out
 	"
 
 test_expect_success 'run log against a from trunk' "
 	git reset --hard origin/trunk &&
 	git svn log -r3 origin/a >out &&
-	grep ^r3 out
+	test_grep ^r3 out
 	"
 
 printf 'r1 \nr2 \nr4 \n' > expected-range-r1-r2-r4
diff --git a/t/t9117-git-svn-init-clone.sh b/t/t9117-git-svn-init-clone.sh
index 3b038c338f..c5d2617823 100755
--- a/t/t9117-git-svn-init-clone.sh
+++ b/t/t9117-git-svn-init-clone.sh
@@ -49,7 +49,7 @@ test_expect_success 'clone to target directory with --stdlayout' '
 test_expect_success 'init without -s/-T/-b/-t does not warn' '
 	test ! -d trunk &&
 	git svn init "$svnrepo"/project/trunk trunk 2>warning &&
-	! grep -q prefix warning &&
+	test_grep ! prefix warning &&
 	rm -rf trunk &&
 	rm -f warning
 	'
@@ -57,7 +57,7 @@ test_expect_success 'init without -s/-T/-b/-t does not warn' '
 test_expect_success 'clone without -s/-T/-b/-t does not warn' '
 	test ! -d trunk &&
 	git svn clone "$svnrepo"/project/trunk 2>warning &&
-	! grep -q prefix warning &&
+	test_grep ! prefix warning &&
 	rm -rf trunk &&
 	rm -f warning
 	'
@@ -80,7 +80,7 @@ EOF
 test_expect_success 'init with -s/-T/-b/-t assumes --prefix=origin/' '
 	test ! -d project &&
 	git svn init -s "$svnrepo"/project project 2>warning &&
-	! grep -q prefix warning &&
+	test_grep ! prefix warning &&
 	test_svn_configured_prefix "origin/" &&
 	rm -rf project &&
 	rm -f warning
@@ -89,7 +89,7 @@ test_expect_success 'init with -s/-T/-b/-t assumes --prefix=origin/' '
 test_expect_success 'clone with -s/-T/-b/-t assumes --prefix=origin/' '
 	test ! -d project &&
 	git svn clone -s "$svnrepo"/project 2>warning &&
-	! grep -q prefix warning &&
+	test_grep ! prefix warning &&
 	test_svn_configured_prefix "origin/" &&
 	rm -rf project &&
 	rm -f warning
@@ -98,7 +98,7 @@ test_expect_success 'clone with -s/-T/-b/-t assumes --prefix=origin/' '
 test_expect_success 'init with -s/-T/-b/-t and --prefix "" still works' '
 	test ! -d project &&
 	git svn init -s "$svnrepo"/project project --prefix "" 2>warning &&
-	! grep -q prefix warning &&
+	test_grep ! prefix warning &&
 	test_svn_configured_prefix "" &&
 	rm -rf project &&
 	rm -f warning
@@ -107,7 +107,7 @@ test_expect_success 'init with -s/-T/-b/-t and --prefix "" still works' '
 test_expect_success 'clone with -s/-T/-b/-t and --prefix "" still works' '
 	test ! -d project &&
 	git svn clone -s "$svnrepo"/project --prefix "" 2>warning &&
-	! grep -q prefix warning &&
+	test_grep ! prefix warning &&
 	test_svn_configured_prefix "" &&
 	rm -rf project &&
 	rm -f warning
diff --git a/t/t9119-git-svn-info.sh b/t/t9119-git-svn-info.sh
index 088d1c57a8..0dbb2e4a97 100755
--- a/t/t9119-git-svn-info.sh
+++ b/t/t9119-git-svn-info.sh
@@ -333,27 +333,27 @@ test_expect_success 'info unknown-file' "
 	echo two > gitwc/unknown-file &&
 	(cd gitwc && test_must_fail git svn info unknown-file) \
 		 2> actual.info-unknown-file &&
-	grep unknown-file actual.info-unknown-file
+	test_grep unknown-file actual.info-unknown-file
 	"
 
 test_expect_success 'info --url unknown-file' '
 	echo two > gitwc/unknown-file &&
 	(cd gitwc && test_must_fail git svn info --url unknown-file) \
 		 2> actual.info-url-unknown-file &&
-	grep unknown-file actual.info-url-unknown-file
+	test_grep unknown-file actual.info-url-unknown-file
 	'
 
 test_expect_success 'info unknown-directory' "
 	mkdir gitwc/unknown-directory svnwc/unknown-directory &&
 	(cd gitwc && test_must_fail git svn info unknown-directory) \
 		 2> actual.info-unknown-directory &&
-	grep unknown-directory actual.info-unknown-directory
+	test_grep unknown-directory actual.info-unknown-directory
 	"
 
 test_expect_success 'info --url unknown-directory' '
 	(cd gitwc && test_must_fail git svn info --url unknown-directory) \
 		 2> actual.info-url-unknown-directory &&
-	grep unknown-directory actual.info-url-unknown-directory
+	test_grep unknown-directory actual.info-url-unknown-directory
 	'
 
 test_expect_success 'info unknown-symlink-file' "
@@ -363,13 +363,13 @@ test_expect_success 'info unknown-symlink-file' "
 	) &&
 	(cd gitwc && test_must_fail git svn info unknown-symlink-file) \
 		 2> actual.info-unknown-symlink-file &&
-	grep unknown-symlink-file actual.info-unknown-symlink-file
+	test_grep unknown-symlink-file actual.info-unknown-symlink-file
 	"
 
 test_expect_success 'info --url unknown-symlink-file' '
 	(cd gitwc && test_must_fail git svn info --url unknown-symlink-file) \
 		 2> actual.info-url-unknown-symlink-file &&
-	grep unknown-symlink-file actual.info-url-unknown-symlink-file
+	test_grep unknown-symlink-file actual.info-url-unknown-symlink-file
 	'
 
 test_expect_success 'info unknown-symlink-directory' "
@@ -379,13 +379,13 @@ test_expect_success 'info unknown-symlink-directory' "
 	) &&
 	(cd gitwc && test_must_fail git svn info unknown-symlink-directory) \
 		 2> actual.info-unknown-symlink-directory &&
-	grep unknown-symlink-directory actual.info-unknown-symlink-directory
+	test_grep unknown-symlink-directory actual.info-unknown-symlink-directory
 	"
 
 test_expect_success 'info --url unknown-symlink-directory' '
 	(cd gitwc && test_must_fail git svn info --url unknown-symlink-directory) \
 		 2> actual.info-url-unknown-symlink-directory &&
-	grep unknown-symlink-directory actual.info-url-unknown-symlink-directory
+	test_grep unknown-symlink-directory actual.info-url-unknown-symlink-directory
 	'
 
 test_done
diff --git a/t/t9122-git-svn-author.sh b/t/t9122-git-svn-author.sh
index 0fc289ae0f..21401ad2b1 100755
--- a/t/t9122-git-svn-author.sh
+++ b/t/t9122-git-svn-author.sh
@@ -57,15 +57,15 @@ test_expect_success 'interact with it via git svn' '
 	test "z$myself" = "z$unaffected" &&
 
 	# Make sure lack of --add-author-from did not add cruft
-	! grep "^    From: A U Thor " actual.2 &&
+	test_grep ! "^    From: A U Thor " actual.2 &&
 
 	# Make sure --add-author-from added cruft
-	grep "^    From: A U Thor " actual.3 &&
-	grep "^    From: A U Thor " actual.4 &&
+	test_grep "^    From: A U Thor " actual.3 &&
+	test_grep "^    From: A U Thor " actual.4 &&
 
 	# Make sure --add-author-from with --use-log-author affected
 	# the authorship information
-	grep "^Author: A U Thor " actual.4 &&
+	test_grep "^Author: A U Thor " actual.4 &&
 
 	# Make sure there are no commit messages with excess blank lines
 	test $(grep "^ " actual.2 | wc -l) = 3 &&
diff --git a/t/t9130-git-svn-authors-file.sh b/t/t9130-git-svn-authors-file.sh
index 90325db909..67a4d889fd 100755
--- a/t/t9130-git-svn-authors-file.sh
+++ b/t/t9130-git-svn-authors-file.sh
@@ -29,9 +29,9 @@ test_expect_success 'imported 2 revisions successfully' '
 		git rev-list refs/remotes/git-svn >actual &&
 		test_line_count = 2 actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn >actual &&
-		grep "^author BBBBBBB BBBBBBB <bb@example\.com> " actual &&
+		test_grep "^author BBBBBBB BBBBBBB <bb@example\.com> " actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn~1 >actual &&
-		grep "^author AAAAAAA AAAAAAA <aa@example\.com> " actual
+		test_grep "^author AAAAAAA AAAAAAA <aa@example\.com> " actual
 	)
 	'
 
@@ -47,9 +47,9 @@ test_expect_success 'continues to import once authors have been added' '
 		git rev-list refs/remotes/git-svn >actual &&
 		test_line_count = 4 actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn >actual &&
-		grep "^author DDDDDDD DDDDDDD <dd@example\.com> " actual &&
+		test_grep "^author DDDDDDD DDDDDDD <dd@example\.com> " actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn~1 >actual &&
-		grep "^author CCCCCCC CCCCCCC <cc@example\.com> " actual
+		test_grep "^author CCCCCCC CCCCCCC <cc@example\.com> " actual
 	)
 	'
 
diff --git a/t/t9138-git-svn-authors-prog.sh b/t/t9138-git-svn-authors-prog.sh
index 5bb38cb23a..5fdf324111 100755
--- a/t/t9138-git-svn-authors-prog.sh
+++ b/t/t9138-git-svn-authors-prog.sh
@@ -48,15 +48,15 @@ test_expect_success 'authors-prog ran correctly' '
 	(
 		cd x &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn~1 >actual &&
-		grep "^author ee-foo <ee-foo@example\.com> " actual &&
+		test_grep "^author ee-foo <ee-foo@example\.com> " actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn~2 >actual &&
-		grep "^author dd <dd@sub\.example\.com> " actual &&
+		test_grep "^author dd <dd@sub\.example\.com> " actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn~3 >actual &&
-		grep "^author cc <cc@sub\.example\.com> " actual &&
+		test_grep "^author cc <cc@sub\.example\.com> " actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn~4 >actual &&
-		grep "^author bb <bb@example\.com> " actual &&
+		test_grep "^author bb <bb@example\.com> " actual &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn~5 >actual &&
-		grep "^author aa <aa@example\.com> " actual
+		test_grep "^author aa <aa@example\.com> " actual
 	)
 '
 
@@ -64,7 +64,7 @@ test_expect_success 'authors-file overrode authors-prog' '
 	(
 		cd x &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn >actual &&
-		grep "^author FFFFFFF FFFFFFF <fFf@other\.example\.com> " actual
+		test_grep "^author FFFFFFF FFFFFFF <fFf@other\.example\.com> " actual
 	)
 '
 
@@ -99,7 +99,7 @@ test_expect_success 'authors-prog handled special characters in username' '
 		cd x &&
 		git svn --authors-prog=../svn-authors-prog fetch &&
 		git rev-list -1 --pretty=raw refs/remotes/git-svn >actual &&
-		grep "^author xyz; touch evil <xyz; touch evil@example\.com> " actual &&
+		test_grep "^author xyz; touch evil <xyz; touch evil@example\.com> " actual &&
 		! test -f evil
 	)
 '
diff --git a/t/t9140-git-svn-reset.sh b/t/t9140-git-svn-reset.sh
index a420b2a87a..c70a3b36a4 100755
--- a/t/t9140-git-svn-reset.sh
+++ b/t/t9140-git-svn-reset.sh
@@ -43,7 +43,7 @@ test_expect_success 'fetch fails on modified hidden file' '
 	  git svn find-rev refs/remotes/git-svn > ../expect &&
 	  test_must_fail git svn fetch 2> ../errors &&
 	  git svn find-rev refs/remotes/git-svn > ../expect2 ) &&
-	grep "not found in commit" errors &&
+	test_grep "not found in commit" errors &&
 	test_cmp expect expect2
 '
 
@@ -59,7 +59,7 @@ test_expect_success 'refetch succeeds not ignoring any files' '
 	( cd g &&
 	  git svn fetch &&
 	  git svn rebase &&
-	  grep "mod hidden" hid/hid.txt
+	  test_grep "mod hidden" hid/hid.txt
 	)
 '
 
diff --git a/t/t9153-git-svn-rewrite-uuid.sh b/t/t9153-git-svn-rewrite-uuid.sh
index 8cb2b5c69c..2387c7d4f2 100755
--- a/t/t9153-git-svn-rewrite-uuid.sh
+++ b/t/t9153-git-svn-rewrite-uuid.sh
@@ -17,9 +17,9 @@ test_expect_success 'load svn repo' "
 
 test_expect_success 'verify uuid' "
 	git cat-file commit refs/remotes/git-svn~0 >actual &&
-	grep '^git-svn-id: .*@2 $uuid$' actual &&
+	test_grep '^git-svn-id: .*@2 $uuid$' actual &&
 	git cat-file commit refs/remotes/git-svn~1 >actual &&
-	grep '^git-svn-id: .*@1 $uuid$' actual
+	test_grep '^git-svn-id: .*@1 $uuid$' actual
 	"
 
 test_done
diff --git a/t/t9200-git-cvsexportcommit.sh b/t/t9200-git-cvsexportcommit.sh
index 581cf3d28f..8e0272df20 100755
--- a/t/t9200-git-cvsexportcommit.sh
+++ b/t/t9200-git-cvsexportcommit.sh
@@ -336,7 +336,7 @@ test_expect_success 'use the same checkout for Git and CVS' '
 	 echo Hello >> " space" &&
 	 git commit -m "Another change" " space" &&
 	 git cvsexportcommit -W -p -u -c HEAD &&
-	 grep Hello " space" &&
+	 test_grep Hello " space" &&
 	 git diff-files)
 
 '
diff --git a/t/t9210-scalar.sh b/t/t9210-scalar.sh
index f2a6df77ce..c8463d0ac4 100755
--- a/t/t9210-scalar.sh
+++ b/t/t9210-scalar.sh
@@ -21,13 +21,13 @@ test_expect_success 'scalar invoked on enlistment root' '
 		# Register
 		scalar register ${enlistment_root} &&
 		scalar list >out &&
-		grep "$(pwd)/${enlistment_root}/src\$" out &&
+		test_grep "$(pwd)/${enlistment_root}/src\$" out &&
 
 		# Delete (including enlistment root)
 		scalar delete $enlistment_root &&
 		test_path_is_missing $enlistment_root &&
 		scalar list >out &&
-		! grep "^$(pwd)/${enlistment_root}/src\$" out || return 1
+		test_grep ! "^$(pwd)/${enlistment_root}/src\$" out || return 1
 	done
 '
 
@@ -41,13 +41,13 @@ test_expect_success 'scalar invoked on enlistment src repo' '
 		# Register
 		scalar register ${enlistment_root}/src &&
 		scalar list >out &&
-		grep "$(pwd)/${enlistment_root}/src\$" out &&
+		test_grep "$(pwd)/${enlistment_root}/src\$" out &&
 
 		# Delete (will not include enlistment root)
 		scalar delete ${enlistment_root}/src &&
 		test_path_is_dir $enlistment_root &&
 		scalar list >out &&
-		! grep "^$(pwd)/${enlistment_root}/src\$" out || return 1
+		test_grep ! "^$(pwd)/${enlistment_root}/src\$" out || return 1
 	done
 '
 
@@ -61,13 +61,13 @@ test_expect_success 'scalar invoked when enlistment root and repo are the same'
 		# Register
 		scalar register ${enlistment_root} &&
 		scalar list >out &&
-		grep "$(pwd)/${enlistment_root}\$" out &&
+		test_grep "$(pwd)/${enlistment_root}\$" out &&
 
 		# Delete (will not include enlistment root)
 		scalar delete ${enlistment_root} &&
 		test_path_is_missing $enlistment_root &&
 		scalar list >out &&
-		! grep "^$(pwd)/${enlistment_root}\$" out &&
+		test_grep ! "^$(pwd)/${enlistment_root}\$" out &&
 
 		# Make sure we did not accidentally delete the trash dir
 		test_path_is_dir "$TRASH_DIRECTORY" || return 1
@@ -81,7 +81,7 @@ test_expect_success 'scalar repo search respects GIT_CEILING_DIRECTORIES' '
 	mkdir -p test/src/deep &&
 	GIT_CEILING_DIRECTORIES="$(pwd)/test/src" &&
 	! scalar register test/src/deep 2>err &&
-	grep "not a git repository" err
+	test_grep "not a git repository" err
 '
 
 test_expect_success 'scalar enlistments need a worktree' '
@@ -89,11 +89,11 @@ test_expect_success 'scalar enlistments need a worktree' '
 
 	git init --bare bare/src &&
 	! scalar register bare/src 2>err &&
-	grep "Scalar enlistments require a worktree" err &&
+	test_grep "Scalar enlistments require a worktree" err &&
 
 	git init test/src &&
 	! scalar register test/src/.git 2>err &&
-	grep "Scalar enlistments require a worktree" err
+	test_grep "Scalar enlistments require a worktree" err
 '
 
 test_expect_success FSMONITOR_DAEMON 'scalar register starts fsmon daemon' '
@@ -108,7 +108,7 @@ test_expect_success 'scalar register warns when background maintenance fails' '
 	git init register-repo &&
 	GIT_TEST_MAINT_SCHEDULER="crontab:false,launchctl:false,schtasks:false" \
 		scalar register register-repo 2>err &&
-	grep "could not toggle maintenance" err
+	test_grep "could not toggle maintenance" err
 '
 
 test_expect_success 'scalar unregister' '
@@ -117,13 +117,13 @@ test_expect_success 'scalar unregister' '
 	git config --get --global --fixed-value \
 		maintenance.repo "$(pwd)/vanish/src" &&
 	scalar list >scalar.repos &&
-	grep -F "$(pwd)/vanish/src" scalar.repos &&
+	test_grep -F "$(pwd)/vanish/src" scalar.repos &&
 	rm -rf vanish/src/.git &&
 	scalar unregister vanish &&
 	test_must_fail git config --get --global --fixed-value \
 		maintenance.repo "$(pwd)/vanish/src" &&
 	scalar list >scalar.repos &&
-	! grep -F "$(pwd)/vanish/src" scalar.repos &&
+	test_grep ! -F "$(pwd)/vanish/src" scalar.repos &&
 
 	# scalar unregister should be idempotent
 	scalar unregister vanish
@@ -278,7 +278,7 @@ test_expect_success '`reconfigure -a` removes stale config entries' '
 	git init stale/src &&
 	scalar register stale &&
 	scalar list >scalar.repos &&
-	grep stale scalar.repos &&
+	test_grep stale scalar.repos &&
 
 	grep -v stale scalar.repos >expect &&
 
@@ -307,7 +307,7 @@ test_expect_success 'scalar supports -c/-C' '
 
 test_expect_success '`scalar [...] <dir>` errors out when dir is missing' '
 	! scalar run config cloned 2>err &&
-	grep "cloned. does not exist" err
+	test_grep "cloned. does not exist" err
 '
 
 SQ="'"
@@ -318,7 +318,7 @@ test_expect_success UNZIP 'scalar diagnose' '
 	echo "$(pwd)/.git/objects/" >>cloned/src/.git/objects/info/alternates &&
 	test_commit -C cloned/src loose &&
 	scalar diagnose cloned >out 2>err &&
-	grep "Available space" out &&
+	test_grep "Available space" out &&
 	sed -n "s/.*$SQ\\(.*\\.zip\\)$SQ.*/\\1/p" <err >zip_path &&
 	zip_path=$(cat zip_path) &&
 	test -n "$zip_path" &&
@@ -328,9 +328,9 @@ test_expect_success UNZIP 'scalar diagnose' '
 	"$GIT_UNZIP" -p "$zip_path" diagnostics.log >out &&
 	test_file_not_empty out &&
 	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
-	grep "$(pwd)/.git/objects" out &&
+	test_grep "$(pwd)/.git/objects" out &&
 	"$GIT_UNZIP" -p "$zip_path" objects-local.txt >out &&
-	grep "^Total: [1-9]" out
+	test_grep "^Total: [1-9]" out
 '
 
 test_done
diff --git a/t/t9211-scalar-clone.sh b/t/t9211-scalar-clone.sh
index 2043f48a1a..002d6ecdc1 100755
--- a/t/t9211-scalar-clone.sh
+++ b/t/t9211-scalar-clone.sh
@@ -86,7 +86,7 @@ test_expect_success 'fall back on full clone if partial unsupported' '
 	test_config -C to-clone uploadpack.allowanysha1inwant false &&
 
 	scalar clone "file://$(pwd)/to-clone" $enlistment 2>err &&
-	grep "filtering not recognized by server, ignoring" err &&
+	test_grep "filtering not recognized by server, ignoring" err &&
 
 	(
 		cd $enlistment/src &&
@@ -133,7 +133,7 @@ test_expect_success '--single-branch clones HEAD only' '
 		cd $enlistment/src &&
 		git for-each-ref refs/remotes/origin >out &&
 		test_line_count = 2 out &&
-		grep "refs/remotes/origin/base" out
+		test_grep "refs/remotes/origin/base" out
 	) &&
 
 	cleanup_clone $enlistment
@@ -147,8 +147,8 @@ test_expect_success '--no-single-branch clones all branches' '
 		cd $enlistment/src &&
 		git for-each-ref refs/remotes/origin >out &&
 		test_line_count = 3 out &&
-		grep "refs/remotes/origin/base" out &&
-		grep "refs/remotes/origin/parallel" out
+		test_grep "refs/remotes/origin/base" out &&
+		test_grep "refs/remotes/origin/parallel" out
 	) &&
 
 	cleanup_clone $enlistment
@@ -174,15 +174,15 @@ test_expect_success 'progress without tty' '
 	test_config -C to-clone uploadpack.allowanysha1inwant true &&
 
 	GIT_PROGRESS_DELAY=0 scalar clone "file://$(pwd)/to-clone" "$enlistment" 2>stderr &&
-	! grep "Enumerating objects" stderr &&
-	! grep "Updating files" stderr &&
+	test_grep ! "Enumerating objects" stderr &&
+	test_grep ! "Updating files" stderr &&
 	cleanup_clone $enlistment
 '
 
 test_expect_success 'scalar clone warns when background maintenance fails' '
 	GIT_TEST_MAINT_SCHEDULER="crontab:false,launchctl:false,schtasks:false" \
 		scalar clone "file://$(pwd)/to-clone" maint-fail 2>err &&
-	grep "could not toggle maintenance" err
+	test_grep "could not toggle maintenance" err
 '
 
 test_expect_success 'scalar clone --no-maintenance' '
@@ -190,7 +190,7 @@ test_expect_success 'scalar clone --no-maintenance' '
 	GIT_TRACE2_EVENT="$(pwd)/no-maint.event" \
 	GIT_TRACE2_EVENT_DEPTH=100 \
 		scalar clone --no-maintenance "file://$(pwd)/to-clone" no-maint 2>err &&
-	! grep "could not toggle maintenance" err &&
+	test_grep ! "could not toggle maintenance" err &&
 	test_subcommand ! git maintenance unregister --force <no-maint.event
 '
 
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 479437760b..fe6c2617ac 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -436,7 +436,7 @@ test_expect_success 'B: accept invalid timezone with raw-permissive' '
 	git init invalid-timezone &&
 	git -C invalid-timezone fast-import --date-format=raw-permissive <input &&
 	git -C invalid-timezone cat-file -p invalid-timezone >out &&
-	grep "1234567890 [+]051800" out
+	test_grep "1234567890 [+]051800" out
 '
 
 test_expect_success 'B: accept and fixup committer with no name' '
@@ -2326,7 +2326,7 @@ test_expect_success 'R: export-marks feature results in a marks file being creat
 	EOF
 
 	git fast-import --allow-unsafe-features <input &&
-	grep :1 git.marks
+	test_grep :1 git.marks
 '
 
 test_expect_success 'R: export-marks options can be overridden by commandline options' '
@@ -2340,7 +2340,7 @@ test_expect_success 'R: export-marks options can be overridden by commandline op
 	EOF
 	git fast-import --allow-unsafe-features \
 			--export-marks=cmdline-sub/other.marks <input &&
-	grep :1 cmdline-sub/other.marks &&
+	test_grep :1 cmdline-sub/other.marks &&
 	test_path_is_missing feature-sub
 '
 
@@ -3816,9 +3816,9 @@ test_expect_success 'X: replace ref that becomes useless is removed' '
 		sed -e s/othername/somename/ tmp >tmp2 &&
 		git fast-import --force <tmp2 2>msgs &&
 
-		grep "dropping.*since it would point to itself" msgs &&
+		test_grep "dropping.*since it would point to itself" msgs &&
 		git show-ref >refs &&
-		! grep refs/replace refs
+		test_grep ! refs/replace refs
 	)
 '
 
diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index 784d68b6e5..a487476ad4 100755
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -139,9 +139,9 @@ test_expect_success ICONV 'reencoding iso-8859-7' '
 	test $(($(test_oid hexsz) + 181)) -eq "$(git -C new cat-file -s i18n)" &&
 	# ...and for the expected translation of bytes.
 	git -C new cat-file commit i18n >actual &&
-	grep $(printf "\317\200") actual &&
+	test_grep $(printf "\317\200") actual &&
 	# Also make sure the commit does not have the "encoding" header
-	! grep ^encoding actual
+	test_grep ! ^encoding actual
 '
 
 test_expect_success 'aborting on iso-8859-7' '
@@ -170,9 +170,9 @@ test_expect_success 'preserving iso-8859-7' '
 	test $(($(test_oid hexsz) + 200)) -eq "$(git -C new cat-file -s i18n-no-recoding)" &&
 	# ...as well as the expected byte.
 	git -C new cat-file commit i18n-no-recoding >actual &&
-	grep $(printf "\360") actual &&
+	test_grep $(printf "\360") actual &&
 	# Also make sure the commit has the "encoding" header
-	grep ^encoding actual
+	test_grep ^encoding actual
 '
 
 test_expect_success 'encoding preserved if reencoding fails' '
@@ -186,13 +186,13 @@ test_expect_success 'encoding preserved if reencoding fails' '
 	git -C new cat-file commit i18n-invalid >actual &&
 
 	# Make sure the commit still has the encoding header
-	grep ^encoding actual &&
+	test_grep ^encoding actual &&
 	# Verify that the commit has the expected size; i.e.
 	# that no bytes were re-encoded to a different encoding.
 	test $(($(test_oid hexsz) + 212)) -eq "$(git -C new cat-file -s i18n-invalid)" &&
 	# ...and check for the original special bytes
-	grep $(printf "\360") actual &&
-	grep $(printf "\377") actual
+	test_grep $(printf "\360") actual &&
+	test_grep $(printf "\377") actual
 '
 
 test_expect_success 'import/export-marks' '
@@ -244,14 +244,14 @@ test_expect_success 'signed-tags=abort' '
 test_expect_success 'signed-tags=verbatim' '
 
 	git fast-export --signed-tags=verbatim sign-your-name > output &&
-	grep PGP output
+	test_grep PGP output
 
 '
 
 test_expect_success 'signed-tags=warn-verbatim' '
 
 	git fast-export --signed-tags=warn-verbatim sign-your-name >output 2>err &&
-	grep PGP output &&
+	test_grep PGP output &&
 	test -s err
 
 '
@@ -261,7 +261,7 @@ test_expect_success 'signed-tags=warn-verbatim' '
 test_expect_success 'signed-tags=warn' '
 
 	git fast-export --signed-tags=warn sign-your-name >output 2>err &&
-	grep PGP output &&
+	test_grep PGP output &&
 	test -s err
 
 '
@@ -269,13 +269,13 @@ test_expect_success 'signed-tags=warn' '
 test_expect_success 'signed-tags=strip' '
 
 	git fast-export --signed-tags=strip sign-your-name > output &&
-	! grep PGP output
+	test_grep ! PGP output
 
 '
 
 test_expect_success 'signed-tags=warn-strip' '
 	git fast-export --signed-tags=warn-strip sign-your-name >output 2>err &&
-	! grep PGP output &&
+	test_grep ! PGP output &&
 	test -s err
 '
 
@@ -345,7 +345,7 @@ test_expect_success GPG 'signed-commits=verbatim' '
 
 	git fast-export --signed-commits=verbatim --reencode=no commit-signing >output &&
 	test_grep -E "^gpgsig $GIT_DEFAULT_HASH openpgp" output &&
-	grep "encoding ISO-8859-1" output &&
+	test_grep "encoding ISO-8859-1" output &&
 	git -C new fast-import <output &&
 	STRIPPED=$(git -C new rev-parse --verify refs/heads/commit-signing) &&
 	test $COMMIT_SIGNING = $STRIPPED
@@ -356,7 +356,7 @@ test_expect_success GPG 'signed-commits=warn-verbatim' '
 
 	git fast-export --signed-commits=warn-verbatim --reencode=no commit-signing >output 2>err &&
 	test_grep -E "^gpgsig $GIT_DEFAULT_HASH openpgp" output &&
-	grep "encoding ISO-8859-1" output &&
+	test_grep "encoding ISO-8859-1" output &&
 	test -s err &&
 	git -C new fast-import <output &&
 	STRIPPED=$(git -C new rev-parse --verify refs/heads/commit-signing) &&
@@ -367,8 +367,8 @@ test_expect_success GPG 'signed-commits=warn-verbatim' '
 test_expect_success GPG 'signed-commits=strip' '
 
 	git fast-export --signed-commits=strip --reencode=no commit-signing >output &&
-	! grep ^gpgsig output &&
-	grep "^encoding ISO-8859-1" output &&
+	test_grep ! ^gpgsig output &&
+	test_grep "^encoding ISO-8859-1" output &&
 	sed "s/commit-signing/commit-strip-signing/" output | git -C new fast-import &&
 	STRIPPED=$(git -C new rev-parse --verify refs/heads/commit-strip-signing) &&
 	test $COMMIT_SIGNING != $STRIPPED
@@ -378,8 +378,8 @@ test_expect_success GPG 'signed-commits=strip' '
 test_expect_success GPG 'signed-commits=warn-strip' '
 
 	git fast-export --signed-commits=warn-strip --reencode=no commit-signing >output 2>err &&
-	! grep ^gpgsig output &&
-	grep "^encoding ISO-8859-1" output &&
+	test_grep ! ^gpgsig output &&
+	test_grep "^encoding ISO-8859-1" output &&
 	test -s err &&
 	sed "s/commit-signing/commit-strip-signing/" output | git -C new fast-import &&
 	STRIPPED=$(git -C new rev-parse --verify refs/heads/commit-strip-signing) &&
@@ -406,7 +406,7 @@ test_expect_success GPGSM 'round-trip X.509 signed commit' '
 	test_grep -E "^gpgsig $GIT_DEFAULT_HASH x509" output &&
 	git -C new fast-import <output &&
 	git -C new cat-file commit refs/heads/x509-signing >actual &&
-	grep "^gpgsig" actual &&
+	test_grep "^gpgsig" actual &&
 	IMPORTED=$(git -C new rev-parse refs/heads/x509-signing) &&
 	test $X509_COMMIT = $IMPORTED
 
@@ -431,7 +431,7 @@ test_expect_success GPGSSH 'round-trip SSH signed commit' '
 	test_grep -E "^gpgsig $GIT_DEFAULT_HASH ssh" output &&
 	git -C new fast-import <output &&
 	git -C new cat-file commit refs/heads/ssh-signing >actual &&
-	grep "^gpgsig" actual &&
+	test_grep "^gpgsig" actual &&
 	IMPORTED=$(git -C new rev-parse refs/heads/ssh-signing) &&
 	test $SSH_COMMIT = $IMPORTED
 
@@ -520,7 +520,7 @@ test_expect_success 'fast-export -C -C | fast-import' '
 	mkdir new &&
 	git --git-dir=new/.git init &&
 	git fast-export -C -C --signed-tags=strip --all > output &&
-	grep "^C file2 file4\$" output &&
+	test_grep "^C file2 file4\$" output &&
 	git -C new fast-import <output &&
 	test $ENTRY = $(git -C new rev-parse --verify refs/heads/copy)
 
@@ -548,11 +548,11 @@ test_expect_success 'cope with tagger-less tags' '
 	ANNOTATED_TAG_COUNT=$((ANNOTATED_TAG_COUNT + 1)) &&
 	git fast-export -C -C --signed-tags=strip --all > output &&
 	test $(grep -c "^tag " output) = $ANNOTATED_TAG_COUNT &&
-	! grep "Unspecified Tagger" output &&
+	test_grep ! "Unspecified Tagger" output &&
 	git fast-export -C -C --signed-tags=strip --all \
 		--fake-missing-tagger > output &&
 	test $(grep -c "^tag " output) = $ANNOTATED_TAG_COUNT &&
-	grep "Unspecified Tagger" output
+	test_grep "Unspecified Tagger" output
 
 '
 
@@ -628,7 +628,7 @@ test_expect_success 'rewrite tag predating pathspecs to nothing' '
 		test_commit bar &&
 
 		git fast-export --tag-of-filtered-object=rewrite --all -- bar.t >output &&
-		grep from.$ZERO_OID output
+		test_grep from.$ZERO_OID output
 	)
 '
 
@@ -670,7 +670,7 @@ test_expect_success 'path limiting with import-marks does not lose unmodified fi
 	test_tick &&
 	git commit -mnext file &&
 	git fast-export --import-marks=marks simple -- file file0 >actual &&
-	grep file0 actual
+	test_grep file0 actual
 '
 
 test_expect_success 'path limiting works' '
@@ -753,7 +753,7 @@ test_expect_success 'handling tags of blobs' '
 test_expect_success 'handling nested tags' '
 	git tag -a -m "This is a nested tag" nested muss &&
 	git fast-export --mark-tags nested >output &&
-	grep "^from $ZERO_OID$" output &&
+	test_grep "^from $ZERO_OID$" output &&
 	grep "^tag nested$" output >tag_lines &&
 	test_line_count = 2 tag_lines
 '
@@ -926,7 +926,7 @@ test_expect_success 'merge commit gets exported with --import-marks' '
 
 		echo ":1 $(git rev-parse HEAD^^)" >marks &&
 		git fast-export --import-marks=marks main >out &&
-		grep Yeah out
+		test_grep Yeah out
 	)
 '
 
diff --git a/t/t9351-fast-export-anonymize.sh b/t/t9351-fast-export-anonymize.sh
index 156a647484..ed784a56b0 100755
--- a/t/t9351-fast-export-anonymize.sh
+++ b/t/t9351-fast-export-anonymize.sh
@@ -33,44 +33,44 @@ test_expect_success 'export anonymized stream' '
 
 # this also covers commit messages
 test_expect_success 'stream omits path names' '
-	! grep base stream &&
-	! grep foo stream &&
-	! grep subdir stream &&
-	! grep bar stream &&
-	! grep xyzzy stream
+	test_grep ! base stream &&
+	test_grep ! foo stream &&
+	test_grep ! subdir stream &&
+	test_grep ! bar stream &&
+	test_grep ! xyzzy stream
 '
 
 test_expect_success 'stream contains user-specified names' '
-	grep retain-me stream &&
-	! grep should-not-appear stream &&
-	grep custom-name stream
+	test_grep retain-me stream &&
+	test_grep ! should-not-appear stream &&
+	test_grep custom-name stream
 '
 
 test_expect_success 'stream omits gitlink oids' '
 	# avoid relying on the whole oid to remain hash-agnostic; this is
 	# plenty to be unique within our test case
-	! grep a000000000000000000 stream
+	test_grep ! a000000000000000000 stream
 '
 
 test_expect_success 'stream retains other as refname' '
-	grep other stream
+	test_grep other stream
 '
 
 test_expect_success 'stream omits other refnames' '
-	! grep main stream &&
-	! grep mytag stream &&
-	! grep longtag stream
+	test_grep ! main stream &&
+	test_grep ! mytag stream &&
+	test_grep ! longtag stream
 '
 
 test_expect_success 'stream omits identities' '
-	! grep "$GIT_COMMITTER_NAME" stream &&
-	! grep "$GIT_COMMITTER_EMAIL" stream &&
-	! grep "$GIT_AUTHOR_NAME" stream &&
-	! grep "$GIT_AUTHOR_EMAIL" stream
+	test_grep ! "$GIT_COMMITTER_NAME" stream &&
+	test_grep ! "$GIT_COMMITTER_EMAIL" stream &&
+	test_grep ! "$GIT_AUTHOR_NAME" stream &&
+	test_grep ! "$GIT_AUTHOR_EMAIL" stream
 '
 
 test_expect_success 'stream omits tag message' '
-	! grep "annotated tag" stream
+	test_grep ! "annotated tag" stream
 '
 
 # NOTE: we chdir to the new, anonymized repository
diff --git a/t/t9400-git-cvsserver-server.sh b/t/t9400-git-cvsserver-server.sh
index 4b45398bab..b2379e4671 100755
--- a/t/t9400-git-cvsserver-server.sh
+++ b/t/t9400-git-cvsserver-server.sh
@@ -254,7 +254,7 @@ test_expect_success 'gitcvs.enabled = false' \
    else
      true
    fi &&
-   grep "GITCVS emulation disabled" cvs.log &&
+   test_grep "GITCVS emulation disabled" cvs.log &&
    test ! -d cvswork2'
 
 rm -fr cvswork2
@@ -276,7 +276,7 @@ test_expect_success 'gitcvs.ext.enabled = false' '
 	else
 		true
 	fi &&
-	grep "GITCVS emulation disabled" cvs.log &&
+	test_grep "GITCVS emulation disabled" cvs.log &&
 	test ! -d cvswork2
 '
 
diff --git a/t/t9501-gitweb-standalone-http-status.sh b/t/t9501-gitweb-standalone-http-status.sh
index 32814e75df..1093fda6cb 100755
--- a/t/t9501-gitweb-standalone-http-status.sh
+++ b/t/t9501-gitweb-standalone-http-status.sh
@@ -37,13 +37,13 @@ EOF
 test_expect_success \
     'snapshots: tgz only default format enabled' \
     'gitweb_run "p=.git;a=snapshot;h=HEAD;sf=tgz" &&
-    grep "Status: 200 OK" gitweb.output &&
+    test_grep "Status: 200 OK" gitweb.output &&
     gitweb_run "p=.git;a=snapshot;h=HEAD;sf=tbz2" &&
-    grep "403 - Unsupported snapshot format" gitweb.output &&
+    test_grep "403 - Unsupported snapshot format" gitweb.output &&
     gitweb_run "p=.git;a=snapshot;h=HEAD;sf=txz" &&
-    grep "403 - Snapshot format not allowed" gitweb.output &&
+    test_grep "403 - Snapshot format not allowed" gitweb.output &&
     gitweb_run "p=.git;a=snapshot;h=HEAD;sf=zip" &&
-    grep "403 - Unsupported snapshot format" gitweb.output'
+    test_grep "403 - Unsupported snapshot format" gitweb.output'
 
 
 cat >>gitweb_config.perl <<\EOF
@@ -53,13 +53,13 @@ EOF
 test_expect_success \
     'snapshots: all enabled in default, use default disabled value' \
     'gitweb_run "p=.git;a=snapshot;h=HEAD;sf=tgz" &&
-    grep "Status: 200 OK" gitweb.output &&
+    test_grep "Status: 200 OK" gitweb.output &&
     gitweb_run "p=.git;a=snapshot;h=HEAD;sf=tbz2" &&
-    grep "Status: 200 OK" gitweb.output &&
+    test_grep "Status: 200 OK" gitweb.output &&
     gitweb_run "p=.git;a=snapshot;h=HEAD;sf=txz" &&
-    grep "403 - Snapshot format not allowed" gitweb.output &&
+    test_grep "403 - Snapshot format not allowed" gitweb.output &&
     gitweb_run "p=.git;a=snapshot;h=HEAD;sf=zip" &&
-    grep "Status: 200 OK" gitweb.output'
+    test_grep "Status: 200 OK" gitweb.output'
 
 
 cat >>gitweb_config.perl <<\EOF
@@ -69,7 +69,7 @@ EOF
 test_expect_success \
     'snapshots: zip explicitly disabled' \
     'gitweb_run "p=.git;a=snapshot;h=HEAD;sf=zip" &&
-    grep "403 - Snapshot format not allowed" gitweb.output'
+    test_grep "403 - Snapshot format not allowed" gitweb.output'
 test_debug 'cat gitweb.output'
 
 
@@ -80,7 +80,7 @@ EOF
 test_expect_success \
     'snapshots: tgz explicitly enabled' \
     'gitweb_run "p=.git;a=snapshot;h=HEAD;sf=tgz" &&
-    grep "Status: 200 OK" gitweb.output'
+    test_grep "Status: 200 OK" gitweb.output'
 test_debug 'cat gitweb.headers'
 
 
@@ -89,13 +89,13 @@ test_debug 'cat gitweb.headers'
 
 test_expect_success 'snapshots: good tree-ish id' '
 	gitweb_run "p=.git;a=snapshot;h=main;sf=tgz" &&
-	grep "Status: 200 OK" gitweb.output
+	test_grep "Status: 200 OK" gitweb.output
 '
 test_debug 'cat gitweb.headers'
 
 test_expect_success 'snapshots: bad tree-ish id' '
 	gitweb_run "p=.git;a=snapshot;h=frizzumFrazzum;sf=tgz" &&
-	grep "404 - Object does not exist" gitweb.output
+	test_grep "404 - Object does not exist" gitweb.output
 '
 test_debug 'cat gitweb.output'
 
@@ -105,20 +105,20 @@ test_expect_success 'snapshots: bad tree-ish id (tagged object)' '
 	test_tick && git commit -m "Object to be tagged" &&
 	git tag tagged-object $(git hash-object tag-object) &&
 	gitweb_run "p=.git;a=snapshot;h=tagged-object;sf=tgz" &&
-	grep "400 - Object is not a tree-ish" gitweb.output
+	test_grep "400 - Object is not a tree-ish" gitweb.output
 '
 test_debug 'cat gitweb.output'
 
 test_expect_success 'snapshots: good object id' '
 	ID=$(git rev-parse --verify HEAD) &&
 	gitweb_run "p=.git;a=snapshot;h=$ID;sf=tgz" &&
-	grep "Status: 200 OK" gitweb.output
+	test_grep "Status: 200 OK" gitweb.output
 '
 test_debug 'cat gitweb.headers'
 
 test_expect_success 'snapshots: bad object id' '
 	gitweb_run "p=.git;a=snapshot;h=abcdef01234;sf=tgz" &&
-	grep "404 - Object does not exist" gitweb.output
+	test_grep "404 - Object does not exist" gitweb.output
 '
 test_debug 'cat gitweb.output'
 
@@ -127,8 +127,8 @@ test_debug 'cat gitweb.output'
 
 test_expect_success DATE_PARSER 'modification: feed last-modified' '
 	gitweb_run "p=.git;a=atom;h=main" &&
-	grep "Status: 200 OK" gitweb.headers &&
-	grep "Last-modified: Thu, 7 Apr 2005 22:14:13 +0000" gitweb.headers
+	test_grep "Status: 200 OK" gitweb.headers &&
+	test_grep "Last-modified: Thu, 7 Apr 2005 22:14:13 +0000" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
@@ -137,7 +137,7 @@ test_expect_success DATE_PARSER 'modification: feed if-modified-since (modified)
 	export HTTP_IF_MODIFIED_SINCE &&
 	test_when_finished "unset HTTP_IF_MODIFIED_SINCE" &&
 	gitweb_run "p=.git;a=atom;h=main" &&
-	grep "Status: 200 OK" gitweb.headers
+	test_grep "Status: 200 OK" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
@@ -146,14 +146,14 @@ test_expect_success DATE_PARSER 'modification: feed if-modified-since (unmodifie
 	export HTTP_IF_MODIFIED_SINCE &&
 	test_when_finished "unset HTTP_IF_MODIFIED_SINCE" &&
 	gitweb_run "p=.git;a=atom;h=main" &&
-	grep "Status: 304 Not Modified" gitweb.headers
+	test_grep "Status: 304 Not Modified" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
 test_expect_success DATE_PARSER 'modification: snapshot last-modified' '
 	gitweb_run "p=.git;a=snapshot;h=main;sf=tgz" &&
-	grep "Status: 200 OK" gitweb.headers &&
-	grep "Last-modified: Thu, 7 Apr 2005 22:14:13 +0000" gitweb.headers
+	test_grep "Status: 200 OK" gitweb.headers &&
+	test_grep "Last-modified: Thu, 7 Apr 2005 22:14:13 +0000" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
@@ -162,7 +162,7 @@ test_expect_success DATE_PARSER 'modification: snapshot if-modified-since (modif
 	export HTTP_IF_MODIFIED_SINCE &&
 	test_when_finished "unset HTTP_IF_MODIFIED_SINCE" &&
 	gitweb_run "p=.git;a=snapshot;h=main;sf=tgz" &&
-	grep "Status: 200 OK" gitweb.headers
+	test_grep "Status: 200 OK" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
@@ -171,7 +171,7 @@ test_expect_success DATE_PARSER 'modification: snapshot if-modified-since (unmod
 	export HTTP_IF_MODIFIED_SINCE &&
 	test_when_finished "unset HTTP_IF_MODIFIED_SINCE" &&
 	gitweb_run "p=.git;a=snapshot;h=main;sf=tgz" &&
-	grep "Status: 304 Not Modified" gitweb.headers
+	test_grep "Status: 304 Not Modified" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
@@ -181,8 +181,8 @@ test_expect_success DATE_PARSER 'modification: tree snapshot' '
 	export HTTP_IF_MODIFIED_SINCE &&
 	test_when_finished "unset HTTP_IF_MODIFIED_SINCE" &&
 	gitweb_run "p=.git;a=snapshot;h=$ID;sf=tgz" &&
-	grep "Status: 200 OK" gitweb.headers &&
-	! grep -i "last-modified" gitweb.headers
+	test_grep "Status: 200 OK" gitweb.headers &&
+	test_grep ! -i "last-modified" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
@@ -196,8 +196,8 @@ EOF
 
 test_expect_success 'load checking: load too high (default action)' '
 	gitweb_run "p=.git" &&
-	grep "Status: 503 Service Unavailable" gitweb.headers &&
-	grep "503 - The load average on the server is too high" gitweb.body
+	test_grep "Status: 503 Service Unavailable" gitweb.headers &&
+	test_grep "503 - The load average on the server is too high" gitweb.body
 '
 test_debug 'cat gitweb.headers'
 
@@ -212,8 +212,8 @@ EOF
 
 test_expect_success 'invalid arguments: invalid regexp (in project search)' '
 	gitweb_run "a=project_list;s=*\.git;sr=1" &&
-	grep "Status: 400" gitweb.headers &&
-	grep "400 - Invalid.*regexp" gitweb.body
+	test_grep "Status: 400" gitweb.headers &&
+	test_grep "400 - Invalid.*regexp" gitweb.body
 '
 test_debug 'cat gitweb.headers'
 
diff --git a/t/t9502-gitweb-standalone-parse-output.sh b/t/t9502-gitweb-standalone-parse-output.sh
index 81d5625557..d8280d17e5 100755
--- a/t/t9502-gitweb-standalone-parse-output.sh
+++ b/t/t9502-gitweb-standalone-parse-output.sh
@@ -111,7 +111,7 @@ test_debug 'cat gitweb.headers && cat file_list'
 
 test_expect_success 'snapshot: hierarchical branch name (xx/test)' '
 	gitweb_run "p=.git;a=snapshot;h=xx/test;sf=tar" &&
-	! grep "filename=.*/" gitweb.headers
+	test_grep ! "filename=.*/" gitweb.headers
 '
 test_debug 'cat gitweb.headers'
 
@@ -139,13 +139,13 @@ test_expect_success 'forks: setup' '
 
 test_expect_success 'forks: not skipped unless "forks" feature enabled' '
 	gitweb_run "a=project_list" &&
-	grep -q ">\\.git<"               gitweb.body &&
-	grep -q ">foo\\.git<"            gitweb.body &&
-	grep -q ">foo_baz\\.git<"        gitweb.body &&
-	grep -q ">foo\\.bar\\.git<"      gitweb.body &&
-	grep -q ">foo_baz\\.git<"        gitweb.body &&
-	grep -q ">foo/foo-forked\\.git<" gitweb.body &&
-	grep -q ">fork of .*<"           gitweb.body
+	test_grep ">\\.git<"               gitweb.body &&
+	test_grep ">foo\\.git<"            gitweb.body &&
+	test_grep ">foo_baz\\.git<"        gitweb.body &&
+	test_grep ">foo\\.bar\\.git<"      gitweb.body &&
+	test_grep ">foo_baz\\.git<"        gitweb.body &&
+	test_grep ">foo/foo-forked\\.git<" gitweb.body &&
+	test_grep ">fork of .*<"           gitweb.body
 '
 
 test_expect_success 'enable forks feature' '
@@ -156,25 +156,25 @@ test_expect_success 'enable forks feature' '
 
 test_expect_success 'forks: forks skipped if "forks" feature enabled' '
 	gitweb_run "a=project_list" &&
-	grep -q ">\\.git<"               gitweb.body &&
-	grep -q ">foo\\.git<"            gitweb.body &&
-	grep -q ">foo_baz\\.git<"        gitweb.body &&
-	grep -q ">foo\\.bar\\.git<"      gitweb.body &&
-	grep -q ">foo_baz\\.git<"        gitweb.body &&
-	grep -v ">foo/foo-forked\\.git<" gitweb.body &&
-	grep -v ">fork of .*<"           gitweb.body
+	test_grep ">\\.git<"               gitweb.body &&
+	test_grep ">foo\\.git<"            gitweb.body &&
+	test_grep ">foo_baz\\.git<"        gitweb.body &&
+	test_grep ">foo\\.bar\\.git<"      gitweb.body &&
+	test_grep ">foo_baz\\.git<"        gitweb.body &&
+	test_grep -v ">foo/foo-forked\\.git<" gitweb.body &&
+	test_grep -v ">fork of .*<"           gitweb.body
 '
 
 test_expect_success 'forks: "forks" action for forked repository' '
 	gitweb_run "p=foo.git;a=forks" &&
-	grep -q ">foo/foo-forked\\.git<" gitweb.body &&
-	grep -q ">fork of foo<"          gitweb.body
+	test_grep ">foo/foo-forked\\.git<" gitweb.body &&
+	test_grep ">fork of foo<"          gitweb.body
 '
 
 test_expect_success 'forks: can access forked repository' '
 	gitweb_run "p=foo/foo-forked.git;a=summary" &&
-	grep -q "200 OK"        gitweb.headers &&
-	grep -q ">fork of foo<" gitweb.body
+	test_grep "200 OK"        gitweb.headers &&
+	test_grep ">fork of foo<" gitweb.body
 '
 
 test_expect_success 'forks: project_index lists all projects (incl. forks)' '
diff --git a/t/t9800-git-p4-basic.sh b/t/t9800-git-p4-basic.sh
index 0816763e46..140a3a7f24 100755
--- a/t/t9800-git-p4-basic.sh
+++ b/t/t9800-git-p4-basic.sh
@@ -35,7 +35,7 @@ test_expect_success 'basic git p4 clone' '
 
 test_expect_success 'depot typo error' '
 	test_must_fail git p4 clone --dest="$git" /depot 2>errs &&
-	grep "Depot paths must start with" errs
+	test_grep "Depot paths must start with" errs
 '
 
 test_expect_success 'git p4 clone @all' '
@@ -356,7 +356,7 @@ test_expect_success 'unresolvable host in P4PORT should display error' '
 		P4PORT=nosuchhost:65537 &&
 		export P4PORT &&
 		test_expect_code 1 git p4 sync >out 2>err &&
-		grep "connect to nosuchhost" err
+		test_grep "connect to nosuchhost" err
 	)
 '
 
@@ -374,7 +374,7 @@ test_expect_success 'run hook p4-pre-submit before submit' '
 		git commit -m "add hello.txt" &&
 		git config git-p4.skipSubmitEdit true &&
 		git p4 submit --dry-run >out &&
-		grep "Would apply" out
+		test_grep "Would apply" out
 	) &&
 	test_hook -C "$git" p4-pre-submit <<-\EOF &&
 	exit 0
@@ -382,7 +382,7 @@ test_expect_success 'run hook p4-pre-submit before submit' '
 	(
 		cd "$git" &&
 		git p4 submit --dry-run >out &&
-		grep "Would apply" out
+		test_grep "Would apply" out
 	) &&
 	test_hook -C "$git" --clobber p4-pre-submit <<-\EOF &&
 	exit 1
@@ -390,7 +390,7 @@ test_expect_success 'run hook p4-pre-submit before submit' '
 	(
 		cd "$git" &&
 		test_must_fail git p4 submit --dry-run >errs 2>&1 &&
-		! grep "Would apply" errs
+		test_grep ! "Would apply" errs
 	)
 '
 
diff --git a/t/t9801-git-p4-branch.sh b/t/t9801-git-p4-branch.sh
index c598011635..9912b48151 100755
--- a/t/t9801-git-p4-branch.sh
+++ b/t/t9801-git-p4-branch.sh
@@ -216,17 +216,17 @@ test_expect_success 'git p4 clone simple branches' '
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch2 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test ! -f file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch3 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		cd "$cli" &&
 		cd branch1 &&
 		p4 edit file2 &&
@@ -235,7 +235,7 @@ test_expect_success 'git p4 clone simple branches' '
 		cd "$git" &&
 		git reset --hard p4/depot/branch1 &&
 		git p4 rebase &&
-		grep file2_ file2
+		test_grep file2_ file2
 	)
 '
 
@@ -292,29 +292,29 @@ test_expect_success 'git p4 clone complex branches' '
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch2 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_missing file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch3 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch4 &&
 		git diff-tree --quiet HEAD &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_missing file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch5 &&
 		git diff-tree --quiet HEAD &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		test_must_fail git show-ref --verify refs/git-p4-tmp
 	)
 '
@@ -346,27 +346,27 @@ test_expect_success 'git p4 sync changes to two branches in the same changelist'
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch2 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_missing file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch3 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_missing file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch4 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch5 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		test_must_fail git show-ref --verify refs/git-p4-tmp
 	)
 '
@@ -398,27 +398,27 @@ test_expect_failure 'git p4 clone file subset branch' '
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch2 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_missing file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch3 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_missing file3 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch4 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch5 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch6 &&
 		test_path_is_file file1 &&
 		test_path_is_missing file2 &&
@@ -622,19 +622,19 @@ test_expect_success 'git p4 clone simple branches with base folder on server sid
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
 		test_path_is_file sub_file1 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		git reset --hard p4/depot/branch2 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test ! -f file3 &&
 		test_path_is_file sub_file1 &&
-		! grep update file2 &&
+		test_grep ! update file2 &&
 		git reset --hard p4/depot/branch3 &&
 		test_path_is_file file1 &&
 		test_path_is_file file2 &&
 		test_path_is_file file3 &&
 		test_path_is_file sub_file1 &&
-		grep update file2 &&
+		test_grep update file2 &&
 		cd "$cli" &&
 		cd branch1 &&
 		p4 edit file2 &&
@@ -643,7 +643,7 @@ test_expect_success 'git p4 clone simple branches with base folder on server sid
 		cd "$git" &&
 		git reset --hard p4/depot/branch1 &&
 		git p4 rebase &&
-		grep file2_ file2
+		test_grep file2_ file2
 	)
 '
 
@@ -661,7 +661,7 @@ test_expect_success 'Update a file in git side and submit to P4 using client vie
 		cd "$cli" &&
 		p4 sync ... &&
 		cd branch1 &&
-		grep "client spec" file1
+		test_grep "client spec" file1
 	)
 '
 
diff --git a/t/t9806-git-p4-options.sh b/t/t9806-git-p4-options.sh
index c26d297433..dce710ea56 100755
--- a/t/t9806-git-p4-options.sh
+++ b/t/t9806-git-p4-options.sh
@@ -49,7 +49,7 @@ test_expect_success 'sync when no master branch prints a nice error' '
 	(
 		cd "$git" &&
 		test_must_fail git p4 sync 2>err &&
-		grep "Error: no branch refs/remotes/p4/master" err
+		test_grep "Error: no branch refs/remotes/p4/master" err
 	)
 '
 
@@ -85,9 +85,9 @@ test_expect_success 'sync when two branches but no master should noop' '
 		git p4 sync --branch=refs/remotes/p4/b2 //depot@2 &&
 		git p4 sync &&
 		git show -s --format=%s refs/remotes/p4/b1 >show &&
-		grep "Initial import" show &&
+		test_grep "Initial import" show &&
 		git show -s --format=%s refs/remotes/p4/b2 >show &&
-		grep "Initial import" show
+		test_grep "Initial import" show
 	)
 '
 
@@ -100,9 +100,9 @@ test_expect_success 'sync --branch updates specific branch, no detection' '
 		git p4 sync --branch=b2 //depot@2 &&
 		git p4 sync --branch=b2 &&
 		git show -s --format=%s refs/remotes/p4/b1 >show &&
-		grep "Initial import" show &&
+		test_grep "Initial import" show &&
 		git show -s --format=%s refs/remotes/p4/b2 >show &&
-		grep "change 3" show
+		test_grep "change 3" show
 	)
 '
 
diff --git a/t/t9807-git-p4-submit.sh b/t/t9807-git-p4-submit.sh
index 6ae7ced51b..73c5953ca7 100755
--- a/t/t9807-git-p4-submit.sh
+++ b/t/t9807-git-p4-submit.sh
@@ -542,7 +542,7 @@ test_expect_success 'submit --update-shelve' '
 		cd "$cli" &&
 		change=$(last_shelve) &&
 		p4 unshelve -c $change -s $change &&
-		grep -q updated-line shelf.t &&
+		test_grep updated-line shelf.t &&
 		p4 describe -S $change | grep added-file.t &&
 		test_path_is_missing shelved-change-1.t &&
 		p4 revert ...
diff --git a/t/t9810-git-p4-rcs.sh b/t/t9810-git-p4-rcs.sh
index 5fe83315ec..70355a32a3 100755
--- a/t/t9810-git-p4-rcs.sh
+++ b/t/t9810-git-p4-rcs.sh
@@ -299,12 +299,12 @@ test_expect_success 'cope with rcs keyword file deletion' '
 		echo "\$Revision\$" >kwdelfile.c &&
 		p4 add -t ktext kwdelfile.c &&
 		p4 submit -d "Add file to be deleted" &&
-		grep 1 kwdelfile.c
+		test_grep 1 kwdelfile.c
 	) &&
 	git p4 clone --dest="$git" //depot &&
 	(
 		cd "$git" &&
-		grep Revision kwdelfile.c &&
+		test_grep Revision kwdelfile.c &&
 		git rm -f kwdelfile.c &&
 		git commit -m "Delete a file containing RCS keywords" &&
 		git config git-p4.skipSubmitEdit true &&
@@ -336,7 +336,7 @@ test_expect_success 'Add keywords in git which match the default p4 values' '
 		cd "$cli" &&
 		p4 sync &&
 		test -f kwfile1.c &&
-		grep "NewKW.*Revision.*[0-9]" kwfile1.c
+		test_grep "NewKW.*Revision.*[0-9]" kwfile1.c
 
 	)
 '
@@ -359,7 +359,7 @@ test_expect_failure 'Add keywords in git which do not match the default p4 value
 	(
 		cd "$cli" &&
 		p4 sync &&
-		grep "NewKW2.*Revision.*[0-9]" kwfile1.c
+		test_grep "NewKW2.*Revision.*[0-9]" kwfile1.c
 
 	)
 '
diff --git a/t/t9813-git-p4-preserve-users.sh b/t/t9813-git-p4-preserve-users.sh
index fd018c87a8..838ddd324c 100755
--- a/t/t9813-git-p4-preserve-users.sh
+++ b/t/t9813-git-p4-preserve-users.sh
@@ -119,20 +119,20 @@ test_expect_success 'not preserving user with mixed authorship' '
 		P4EDITOR=cat P4USER=alice P4PASSWD=secret &&
 		export P4EDITOR P4USER P4PASSWD &&
 		git p4 commit >actual &&
-		grep "git author derek@example.com does not match" actual &&
+		test_grep "git author derek@example.com does not match" actual &&
 
 		make_change_by_user usernamefile3 Charlie charlie@example.com &&
 		git p4 commit >actual &&
-		grep "git author charlie@example.com does not match" actual &&
+		test_grep "git author charlie@example.com does not match" actual &&
 
 		make_change_by_user usernamefile3 alice alice@example.com &&
 		git p4 commit >actual &&
-		! grep "git author.*does not match" actual &&
+		test_grep ! "git author.*does not match" actual &&
 
 		git config git-p4.skipUserNameCheck true &&
 		make_change_by_user usernamefile3 Charlie charlie@example.com &&
 		git p4 commit >actual &&
-		! grep "git author.*does not match" actual &&
+		test_grep ! "git author.*does not match" actual &&
 
 		p4_check_commit_author usernamefile3 alice
 	)
diff --git a/t/t9814-git-p4-rename.sh b/t/t9814-git-p4-rename.sh
index 2a9838f37f..6c5ecb9bea 100755
--- a/t/t9814-git-p4-rename.sh
+++ b/t/t9814-git-p4-rename.sh
@@ -66,7 +66,7 @@ test_expect_success 'detect renames' '
 		git diff-tree -r -M HEAD &&
 		git p4 submit &&
 		p4 filelog //depot/file4 >filelog &&
-		! grep " from //depot" filelog &&
+		test_grep ! " from //depot" filelog &&
 
 		git mv file4 file5 &&
 		git commit -a -m "Rename file4 to file5" &&
@@ -74,7 +74,7 @@ test_expect_success 'detect renames' '
 		git config git-p4.detectRenames true &&
 		git p4 submit &&
 		p4 filelog //depot/file5 >filelog &&
-		grep " from //depot/file4" filelog &&
+		test_grep " from //depot/file4" filelog &&
 
 		git mv file5 file6 &&
 		echo update >>file6 &&
@@ -86,7 +86,7 @@ test_expect_success 'detect renames' '
 		git config git-p4.detectRenames $(($level + 2)) &&
 		git p4 submit &&
 		p4 filelog //depot/file6 >filelog &&
-		! grep " from //depot" filelog &&
+		test_grep ! " from //depot" filelog &&
 
 		git mv file6 file7 &&
 		echo update >>file7 &&
@@ -98,7 +98,7 @@ test_expect_success 'detect renames' '
 		git config git-p4.detectRenames $(($level - 2)) &&
 		git p4 submit &&
 		p4 filelog //depot/file7 >filelog &&
-		grep " from //depot/file6" filelog
+		test_grep " from //depot/file6" filelog
 	)
 '
 
diff --git a/t/t9827-git-p4-change-filetype.sh b/t/t9827-git-p4-change-filetype.sh
index d3670bd7a2..9a8231a788 100755
--- a/t/t9827-git-p4-change-filetype.sh
+++ b/t/t9827-git-p4-change-filetype.sh
@@ -36,7 +36,7 @@ test_expect_success SYMLINKS 'change file to symbolic link' '
 		git commit -m "symlink file1 to file2" &&
 		git p4 submit &&
 		p4 filelog -m 1 //depot/file2 >filelog &&
-		grep "(symlink)" filelog
+		test_grep "(symlink)" filelog
 	)
 '
 
@@ -55,7 +55,7 @@ test_expect_success SYMLINKS 'change symbolic link to file' '
 		git commit -m "re-write file2" &&
 		git p4 submit &&
 		p4 filelog -m 1 //depot/file2 >filelog &&
-		grep "(text)" filelog
+		test_grep "(text)" filelog
 	)
 '
 
diff --git a/t/t9832-unshelve.sh b/t/t9832-unshelve.sh
index 6b3cb0414a..a5e90b9bf7 100755
--- a/t/t9832-unshelve.sh
+++ b/t/t9832-unshelve.sh
@@ -69,7 +69,7 @@ EOF
 		change=$(last_shelved_change) &&
 		git p4 unshelve $change &&
 		git show refs/remotes/p4-unshelved/$change >actual &&
-		grep -q "Further description" actual &&
+		test_grep "Further description" actual &&
 		git cherry-pick refs/remotes/p4-unshelved/$change &&
 		test_path_is_file file2 &&
 		test_cmp file1 "$cli"/file1 &&
@@ -141,7 +141,7 @@ test_expect_success 'create shelved changelist based on p4 change ahead of p4/ma
 		shelve_one_file //depot/file1 &&
 		change=$(last_shelved_change) &&
 		p4 describe -S $change >out.txt &&
-		grep -q "Change to be unshelved" out.txt
+		test_grep "Change to be unshelved" out.txt
 	)
 '
 
@@ -152,7 +152,7 @@ test_expect_success 'try to unshelve the change' '
 		change=$(last_shelved_change) &&
 		cd "$git" &&
 		git p4 unshelve $change >out.txt &&
-		grep -q "unshelved changelist $change" out.txt
+		test_grep "unshelved changelist $change" out.txt
 	)
 '
 
diff --git a/t/t9833-errors.sh b/t/t9833-errors.sh
index e22369ccdf..2fb59cede7 100755
--- a/t/t9833-errors.sh
+++ b/t/t9833-errors.sh
@@ -29,7 +29,7 @@ test_expect_success 'error handling' '
 		P4PASSWD=badpassword &&
 		export P4PASSWD &&
 		test_must_fail git p4 clone //depot/foo 2>errmsg &&
-		grep -q "failure accessing depot.*P4PASSWD" errmsg
+		test_grep "failure accessing depot.*P4PASSWD" errmsg
 	)
 '
 
@@ -41,7 +41,7 @@ test_expect_success 'ticket logged out' '
 		test_commit "ticket-auth-check" &&
 		p4 logout &&
 		test_must_fail git p4 submit 2>errmsg &&
-		grep -q "failure accessing depot" errmsg
+		test_grep "failure accessing depot" errmsg
 	)
 '
 
diff --git a/t/t9835-git-p4-metadata-encoding-python2.sh b/t/t9835-git-p4-metadata-encoding-python2.sh
index b969c7e0d5..7eb0c8ecd1 100755
--- a/t/t9835-git-p4-metadata-encoding-python2.sh
+++ b/t/t9835-git-p4-metadata-encoding-python2.sh
@@ -84,7 +84,7 @@ test_expect_success 'clone non-utf8 repo with strict encoding' '
 	test_when_finished cleanup_git &&
 	test_when_finished remove_user_cache &&
 	test_must_fail git -c git-p4.metadataDecodingStrategy=strict p4-python2 clone --dest="$git" //depot@all 2>err &&
-	grep "Decoding perforce metadata failed!" err
+	test_grep "Decoding perforce metadata failed!" err
 '
 
 test_expect_success 'check utf-8 contents with passthrough strategy' '
@@ -94,8 +94,8 @@ test_expect_success 'check utf-8 contents with passthrough strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "some utf-8 tǣxt" actual &&
-		grep "ǣuthor" actual
+		test_grep "some utf-8 tǣxt" actual &&
+		test_grep "ǣuthor" actual
 	)
 '
 
@@ -107,9 +107,9 @@ test_expect_success 'check latin-1 contents corrupted in git with passthrough st
 		cd "$git" &&
 		git log >actual &&
 		badly_encoded_in_git=$(echo "some latin-1 tæxt" | iconv -f utf8 -t latin1) &&
-		grep "$badly_encoded_in_git" actual &&
+		test_grep "$badly_encoded_in_git" actual &&
 		bad_author_in_git="$(echo æuthor | iconv -f utf8 -t latin1)" &&
-		grep "$bad_author_in_git" actual
+		test_grep "$bad_author_in_git" actual
 	)
 '
 
@@ -120,8 +120,8 @@ test_expect_success 'check utf-8 contents with fallback strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "some utf-8 tǣxt" actual &&
-		grep "ǣuthor" actual
+		test_grep "some utf-8 tǣxt" actual &&
+		test_grep "ǣuthor" actual
 	)
 '
 
@@ -132,8 +132,8 @@ test_expect_success 'check latin-1 contents with fallback strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "some latin-1 tæxt" actual &&
-		grep "æuthor" actual
+		test_grep "some latin-1 tæxt" actual &&
+		test_grep "æuthor" actual
 	)
 '
 
@@ -144,8 +144,8 @@ test_expect_success 'check cp-1252 contents with fallback strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "sœme cp-1252 tæxt" actual &&
-		grep "æuthœr" actual
+		test_grep "sœme cp-1252 tæxt" actual &&
+		test_grep "æuthœr" actual
 	)
 '
 
@@ -156,8 +156,8 @@ test_expect_success 'check cp850 contents parsed with correct fallback' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "hÅs some cp850 text" actual &&
-		grep "Åuthor" actual
+		test_grep "hÅs some cp850 text" actual &&
+		test_grep "Åuthor" actual
 	)
 '
 
@@ -168,8 +168,8 @@ test_expect_success 'check cp850-only contents escaped when cp1252 is fallback'
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "h%8Fs some cp850 text" actual &&
-		grep "%8Futhor" actual
+		test_grep "h%8Fs some cp850 text" actual &&
+		test_grep "%8Futhor" actual
 	)
 '
 
@@ -191,8 +191,8 @@ test_expect_success 'check cp-1252 contents on later sync after clone with fallb
 		git p4-python2 sync --branch=master &&
 
 		git log p4/master >actual &&
-		grep "sœme more cp-1252 tæxt" actual &&
-		grep "æuthœr" actual
+		test_grep "sœme more cp-1252 tæxt" actual &&
+		test_grep "æuthœr" actual
 	)
 '
 
@@ -208,7 +208,7 @@ test_expect_success 'passthrough (latin-1 contents corrupted in git) is the defa
 		cd "$git" &&
 		git log >actual &&
 		badly_encoded_in_git=$(echo "some latin-1 tæxt" | iconv -f utf8 -t latin1) &&
-		grep "$badly_encoded_in_git" actual
+		test_grep "$badly_encoded_in_git" actual
 	)
 '
 
diff --git a/t/t9836-git-p4-metadata-encoding-python3.sh b/t/t9836-git-p4-metadata-encoding-python3.sh
index da6669bf71..16118495cd 100755
--- a/t/t9836-git-p4-metadata-encoding-python3.sh
+++ b/t/t9836-git-p4-metadata-encoding-python3.sh
@@ -84,7 +84,7 @@ test_expect_success 'clone non-utf8 repo with strict encoding' '
 	test_when_finished cleanup_git &&
 	test_when_finished remove_user_cache &&
 	test_must_fail git -c git-p4.metadataDecodingStrategy=strict p4-python3 clone --dest="$git" //depot@all 2>err &&
-	grep "Decoding perforce metadata failed!" err
+	test_grep "Decoding perforce metadata failed!" err
 '
 
 test_expect_success 'check utf-8 contents with passthrough strategy' '
@@ -94,8 +94,8 @@ test_expect_success 'check utf-8 contents with passthrough strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "some utf-8 tǣxt" actual &&
-		grep "ǣuthor" actual
+		test_grep "some utf-8 tǣxt" actual &&
+		test_grep "ǣuthor" actual
 	)
 '
 
@@ -107,9 +107,9 @@ test_expect_success 'check latin-1 contents corrupted in git with passthrough st
 		cd "$git" &&
 		git log >actual &&
 		badly_encoded_in_git=$(echo "some latin-1 tæxt" | iconv -f utf8 -t latin1) &&
-		grep "$badly_encoded_in_git" actual &&
+		test_grep "$badly_encoded_in_git" actual &&
 		bad_author_in_git="$(echo æuthor | iconv -f utf8 -t latin1)" &&
-		grep "$bad_author_in_git" actual
+		test_grep "$bad_author_in_git" actual
 	)
 '
 
@@ -120,8 +120,8 @@ test_expect_success 'check utf-8 contents with fallback strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "some utf-8 tǣxt" actual &&
-		grep "ǣuthor" actual
+		test_grep "some utf-8 tǣxt" actual &&
+		test_grep "ǣuthor" actual
 	)
 '
 
@@ -132,8 +132,8 @@ test_expect_success 'check latin-1 contents with fallback strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "some latin-1 tæxt" actual &&
-		grep "æuthor" actual
+		test_grep "some latin-1 tæxt" actual &&
+		test_grep "æuthor" actual
 	)
 '
 
@@ -144,8 +144,8 @@ test_expect_success 'check cp-1252 contents with fallback strategy' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "sœme cp-1252 tæxt" actual &&
-		grep "æuthœr" actual
+		test_grep "sœme cp-1252 tæxt" actual &&
+		test_grep "æuthœr" actual
 	)
 '
 
@@ -156,8 +156,8 @@ test_expect_success 'check cp850 contents parsed with correct fallback' '
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "hÅs some cp850 text" actual &&
-		grep "Åuthor" actual
+		test_grep "hÅs some cp850 text" actual &&
+		test_grep "Åuthor" actual
 	)
 '
 
@@ -168,8 +168,8 @@ test_expect_success 'check cp850-only contents escaped when cp1252 is fallback'
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "h%8Fs some cp850 text" actual &&
-		grep "%8Futhor" actual
+		test_grep "h%8Fs some cp850 text" actual &&
+		test_grep "%8Futhor" actual
 	)
 '
 
@@ -191,8 +191,8 @@ test_expect_success 'check cp-1252 contents on later sync after clone with fallb
 		git p4-python3 sync --branch=master &&
 
 		git log p4/master >actual &&
-		grep "sœme more cp-1252 tæxt" actual &&
-		grep "æuthœr" actual
+		test_grep "sœme more cp-1252 tæxt" actual &&
+		test_grep "æuthœr" actual
 	)
 '
 
@@ -208,8 +208,8 @@ test_expect_success 'fallback (both utf-8 and cp-1252 contents handled) is the d
 	(
 		cd "$git" &&
 		git log >actual &&
-		grep "sœme cp-1252 tæxt" actual &&
-		grep "æuthœr" actual
+		test_grep "sœme cp-1252 tæxt" actual &&
+		test_grep "æuthœr" actual
 	)
 '
 
diff --git a/t/t9850-shell.sh b/t/t9850-shell.sh
index 21c3af48bd..27cc49bbd1 100755
--- a/t/t9850-shell.sh
+++ b/t/t9850-shell.sh
@@ -32,7 +32,7 @@ test_expect_success 'shell allows interactive command' '
 test_expect_success 'shell complains of overlong commands' '
 	test-tool genzeros | tr "\000" "a" |
 	test_must_fail git shell 2>err &&
-	grep "too long" err
+	test_grep "too long" err
 '
 
 test_done
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 28f61f08fb..382b57d7b4 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -1381,7 +1381,7 @@ test_expect_success '__git_complete_worktree_paths' '
 	test_when_finished "git worktree remove other_wt" &&
 	git worktree add --orphan other_wt &&
 	run_completion "git worktree remove " &&
-	grep other_wt out
+	test_grep other_wt out
 '
 
 test_expect_success '__git_complete_worktree_paths - not a git repository' '
@@ -1397,7 +1397,7 @@ test_expect_success '__git_complete_worktree_paths with -C' '
 	test_when_finished "git -C otherrepo worktree remove otherrepo_wt" &&
 	git -C otherrepo worktree add --orphan otherrepo_wt &&
 	run_completion "git -C otherrepo worktree remove " &&
-	grep otherrepo_wt out
+	test_grep otherrepo_wt out
 '
 
 test_expect_success 'git switch - with no options, complete local branches and unique remote branch names for DWIM logic' '
@@ -2554,14 +2554,14 @@ test_expect_success '__git_pretty_aliases' '
 test_expect_success 'basic' '
 	run_completion "git " &&
 	# built-in
-	grep -q "^add \$" out &&
+	test_grep "^add \$" out &&
 	# script
-	grep -q "^rebase \$" out &&
+	test_grep "^rebase \$" out &&
 	# plumbing
-	! grep -q "^ls-files \$" out &&
+	test_grep ! "^ls-files \$" out &&
 
 	run_completion "git r" &&
-	! grep -q -v "^r" out
+	test_grep ! -v "^r" out
 '
 
 test_expect_success 'double dash "git" itself' '
@@ -2656,7 +2656,7 @@ test_expect_success 'git --help completion' '
 test_expect_success 'completion.commands removes multiple commands' '
 	test_config completion.commands "-cherry -mergetool" &&
 	git --list-cmds=list-mainporcelain,list-complete,config >out &&
-	! grep -E "^(cherry|mergetool)$" out
+	test_grep ! -E "^(cherry|mergetool)$" out
 '
 
 test_expect_success 'setup for integration tests' '
@@ -3179,8 +3179,8 @@ test_expect_success 'plumbing commands are excluded without GIT_COMPLETION_SHOW_
 
 		# Just mainporcelain, not plumbing commands
 		run_completion "git c" &&
-		grep checkout out &&
-		! grep cat-file out
+		test_grep checkout out &&
+		test_grep ! cat-file out
 	)
 '
 
@@ -3193,13 +3193,13 @@ test_expect_success 'all commands are shown with GIT_COMPLETION_SHOW_ALL_COMMAND
 
 		# Both mainporcelain and plumbing commands
 		run_completion "git c" &&
-		grep checkout out &&
-		grep cat-file out &&
+		test_grep checkout out &&
+		test_grep cat-file out &&
 
 		# Check "gitk", a "main" command, but not a built-in + more plumbing
 		run_completion "git g" &&
-		grep gitk out &&
-		grep get-tar-commit-id out
+		test_grep gitk out &&
+		test_grep get-tar-commit-id out
 	)
 '
 
-- 
gitgitgadget