[PATCH v2 0/4] add [ as alias for test, fix 0/1 argument handling

[PATCH v2 0/4] add [ as alias for test, fix 0/1 argument handling

[Rasmus Villemoes]

Make 'test' behave a little more like its cousins in other shells, by
allowing the [ ... ] spelling, and while here, fix up the handling of
a single, non-empty argument to comply with POSIX.

v2: update documentation, add a few more test cases.

CI is happy: https://github.com/u-boot/u-boot/pull/905

v1: https://lore.kernel.org/u-boot/20260311120910.3934114-1-ravi@prevas.dk/

Rasmus Villemoes (4):
  cmd: test: allow using [ as alias for test
  doc: test: document [ ] spelling of test
  test: add tests for left-bracket alias for 'test' command
  cmd: test: fix handling of single-argument form of test

 cmd/test.c             | 30 +++++++++++++++--
 doc/usage/cmd/test.rst |  5 ++-
 test/hush/if.c         | 73 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+), 3 deletions(-)

-- 
2.53.0

[PATCH v2 1/4] cmd: test: allow using [ as alias for test

[Rasmus Villemoes]

I often find myself writing something like

  if [ "$somevar" = 123 ] ; then ...

only to realize that that syntax doesn't work in U-Boot shell, and
must be spelled

  if test "$somevar" = 123 ; then

It only takes a few lines of code to support this POSIX-standardized
alias for test, and helps developers focus on their actual problems
instead of dealing with such unexpected quirks of the shell.

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
---
 cmd/test.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/cmd/test.c b/cmd/test.c
index a9ac07e6143..f0645ef98f1 100644
--- a/cmd/test.c
+++ b/cmd/test.c
@@ -63,6 +63,14 @@ static int do_test(struct cmd_tbl *cmdtp, int flag, int argc,
 	char * const *ap;
 	int i, op, left, adv, expr, last_expr, last_unop, last_binop;
 
+	if (!strcmp(argv[0], "[")) {
+		if (strcmp(argv[argc - 1], "]")) {
+			printf("[: missing terminating ]\n");
+			return 1;
+		}
+		argc--;
+	}
+
 	/* args? */
 	if (argc < 3)
 		return 1;
@@ -212,6 +220,17 @@ U_BOOT_CMD(
 	"[args..]"
 );
 
+/*
+ * This does not use the U_BOOT_CMD macro as [ can't be used in symbol names
+ */
+ll_entry_declare(struct cmd_tbl, lbracket, cmd) = {
+	"[",	CONFIG_SYS_MAXARGS, cmd_always_repeatable, do_test,
+	"alias for 'test'",
+#ifdef CONFIG_SYS_LONGHELP
+	" <test expression> ]"
+#endif /* CONFIG_SYS_LONGHELP */
+};
+
 static int do_false(struct cmd_tbl *cmdtp, int flag, int argc,
 		    char *const argv[])
 {
-- 
2.53.0

[PATCH v2 2/4] doc: test: document [ ] spelling of test

[Rasmus Villemoes]

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
---
 doc/usage/cmd/test.rst | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/doc/usage/cmd/test.rst b/doc/usage/cmd/test.rst
index d1379117fca..037a9ee1774 100644
--- a/doc/usage/cmd/test.rst
+++ b/doc/usage/cmd/test.rst
@@ -20,11 +20,14 @@ Synopsis
     test -e <interface> <dev[:part]> <path>
     test <s> =~ <re>
 
+    [ <test expression> ]
+
 Description
 -----------
 
 The ``test`` command is similar to the ordinary shell built-in by the
-same name. Unlike in ordinary shells, it cannot be spelled ``[``.
+same name. Like in ordinary shells, it can also be spelled ``[``,
+provided the test expression is followed by a separate ``]`` argument.
 
 Strings
 ~~~~~~~
-- 
2.53.0

[PATCH v2 3/4] test: add tests for left-bracket alias for 'test' command

[Rasmus Villemoes]

Duplicate a few of the existing test cases, using the [ spelling, and
also ensure that the presence of a matching ] as a separate and last
argument is enforced.

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
---
 test/hush/if.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/test/hush/if.c b/test/hush/if.c
index ea615b246a9..5f75ea68b32 100644
--- a/test/hush/if.c
+++ b/test/hush/if.c
@@ -315,3 +315,46 @@ static int hush_test_if_z_operator(struct unit_test_state *uts)
 	return 0;
 }
 HUSH_TEST(hush_test_if_z_operator, 0);
+
+static int hush_test_lbracket_alias(struct unit_test_state *uts)
+{
+	char if_formatted[128];
+	const char *missing_rbracket_error = "[: missing terminating ]";
+
+	sprintf(if_formatted, if_format, "[ aaa = aaa ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ aaa = bbb ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ aaa = aaa");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa = bbb");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa = aaa]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa = bbb]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa != aaa -o bbb != bbb ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ aaa != aaa -o bbb = bbb ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ ! aaa != aaa -o ! bbb != bbb ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ ! aaa != aaa -o ! bbb = bbb ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	return 0;
+}
+HUSH_TEST(hush_test_lbracket_alias, UTF_CONSOLE);
-- 
2.53.0

[PATCH v2 4/4] cmd: test: fix handling of single-argument form of test

[Rasmus Villemoes]

POSIX states that

  0 arguments:
      Exit false (1).
  1 argument:
      Exit true (0) if $1 is not null; otherwise, exit false.

and at least bash and busybox sh behave that way.

The current 'argc < 3' does the right thing for a non-existing or
empty argv[1], but not for a non-empty argv[1]. Fix that and add
corresponding test cases.

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
---
 cmd/test.c     | 11 +++++++++--
 test/hush/if.c | 30 ++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/cmd/test.c b/cmd/test.c
index f0645ef98f1..0d0f090386c 100644
--- a/cmd/test.c
+++ b/cmd/test.c
@@ -71,10 +71,17 @@ static int do_test(struct cmd_tbl *cmdtp, int flag, int argc,
 		argc--;
 	}
 
-	/* args? */
-	if (argc < 3)
+	/*
+	 * Per POSIX, 'test' with 0 arguments should return 1, while
+	 * 'test <arg>' should be equivalent to 'test -n <arg>',
+	 * i.e. true if and only if <arg> is not empty.
+	 */
+	if (argc < 2)
 		return 1;
 
+	if (argc == 2)
+		return !strcmp(argv[1], "");
+
 #ifdef DEBUG
 	{
 		debug("test(%d):", argc);
diff --git a/test/hush/if.c b/test/hush/if.c
index 5f75ea68b32..6129e2c530c 100644
--- a/test/hush/if.c
+++ b/test/hush/if.c
@@ -32,6 +32,15 @@ static int hush_test_if_base(struct unit_test_state *uts)
 	sprintf(if_formatted, if_format, "false");
 	ut_asserteq(1, run_command(if_formatted, 0));
 
+	sprintf(if_formatted, if_format, "test");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "test ''");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "test 'abc'");
+	ut_assertok(run_command(if_formatted, 0));
+
 	return 0;
 }
 HUSH_TEST(hush_test_if_base, 0);
@@ -355,6 +364,27 @@ static int hush_test_lbracket_alias(struct unit_test_state *uts)
 	sprintf(if_formatted, if_format, "[ ! aaa != aaa -o ! bbb = bbb ]");
 	ut_assertok(run_command(if_formatted, 0));
 
+	sprintf(if_formatted, if_format, "[ ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ '' ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ ''");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ 'abc' ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ 'abc'");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
 	return 0;
 }
 HUSH_TEST(hush_test_lbracket_alias, UTF_CONSOLE);
-- 
2.53.0

Re: [PATCH v2 0/4] add [ as alias for test, fix 0/1 argument handling

[Anshul Dalal]

On Thu Mar 12, 2026 at 3:31 PM IST, Rasmus Villemoes wrote:
> Make 'test' behave a little more like its cousins in other shells, by
> allowing the [ ... ] spelling, and while here, fix up the handling of
> a single, non-empty argument to comply with POSIX.
>
> v2: update documentation, add a few more test cases.
>
> CI is happy: https://github.com/u-boot/u-boot/pull/905
>
> v1: https://lore.kernel.org/u-boot/20260311120910.3934114-1-ravi@prevas.dk/

Tested-by: Anshul Dalal <anshuld@ti.com>

>
> Rasmus Villemoes (4):
>   cmd: test: allow using [ as alias for test
>   doc: test: document [ ] spelling of test
>   test: add tests for left-bracket alias for 'test' command
>   cmd: test: fix handling of single-argument form of test
>
>  cmd/test.c             | 30 +++++++++++++++--
>  doc/usage/cmd/test.rst |  5 ++-
>  test/hush/if.c         | 73 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 105 insertions(+), 3 deletions(-)

Re: [PATCH v2 0/4] add [ as alias for test, fix 0/1 argument handling

[Tom Rini]

On Thu, 12 Mar 2026 11:01:02 +0100, Rasmus Villemoes wrote:

> Make 'test' behave a little more like its cousins in other shells, by
> allowing the [ ... ] spelling, and while here, fix up the handling of
> a single, non-empty argument to comply with POSIX.
> 
> v2: update documentation, add a few more test cases.
> 
> CI is happy: https://github.com/u-boot/u-boot/pull/905
> 
> [...]

Applied to u-boot/next, thanks!

[1/4] cmd: test: allow using [ as alias for test
      commit: fc8bf9a984c118d551b3f93c66f1ae2733b9b588
[2/4] doc: test: document [ ] spelling of test
      commit: d44f61582947564991cce7501f2e5db0b29ebad6
[3/4] test: add tests for left-bracket alias for 'test' command
      commit: 6f9cc3310a764aaae4478b5a8a0c0cae3b2be4a1
[4/4] cmd: test: fix handling of single-argument form of test
      commit: 8b0619579b2282050e7fb0d92fbc645b79d18bae
-- 
Tom

Re: [PATCH v2 0/4] add [ as alias for test, fix 0/1 argument handling

[Franz Schnyder]

On Wed, Mar 25, 2026 at 05:05:59PM -0600, Tom Rini wrote:
> On Thu, 12 Mar 2026 11:01:02 +0100, Rasmus Villemoes wrote:
> 
> > Make 'test' behave a little more like its cousins in other shells, by
> > allowing the [ ... ] spelling, and while here, fix up the handling of
> > a single, non-empty argument to comply with POSIX.
> > 
> > v2: update documentation, add a few more test cases.
> > 
> > CI is happy: https://github.com/u-boot/u-boot/pull/905
> > 
> > [...]
> 
> Applied to u-boot/next, thanks!
> 
> [1/4] cmd: test: allow using [ as alias for test
>       commit: fc8bf9a984c118d551b3f93c66f1ae2733b9b588
> [2/4] doc: test: document [ ] spelling of test
>       commit: d44f61582947564991cce7501f2e5db0b29ebad6
> [3/4] test: add tests for left-bracket alias for 'test' command
>       commit: 6f9cc3310a764aaae4478b5a8a0c0cae3b2be4a1
> [4/4] cmd: test: fix handling of single-argument form of test
>       commit: 8b0619579b2282050e7fb0d92fbc645b79d18bae
> -- 
> Tom
> 
> 
Hello,

While preparing a patch series based on u-boot/next, I realised that 
the bootflow on our module broke.
I discovered that the issue was introduced with 
commit 8b0619579b2 ("cmd: test: fix handling of single-argument form of test")

This change breaks our boot script as it relies on the behaviour of test
with unquoted empty expansions. For example:

```
test -n ${m4boot} || env set m4boot ';'
```
Is now `test -n`, as there are no quotation marks. It now returns 
true, so the fallback assignment is skipped and it breaks our boot flow.

Any ideas? I think that we will not be the only ones affected by 
this once it's merged into master.
                                                                        
Best regards                                                            
                                                                        
Franz Schnyder     

Re: [PATCH v2 0/4] add [ as alias for test, fix 0/1 argument handling

[Rasmus Villemoes]

On Fri, Mar 27 2026, Franz Schnyder <fra.schnyder@gmail.com> wrote:

> On Wed, Mar 25, 2026 at 05:05:59PM -0600, Tom Rini wrote:
>> On Thu, 12 Mar 2026 11:01:02 +0100, Rasmus Villemoes wrote:
>> 
>> > Make 'test' behave a little more like its cousins in other shells, by
>> > allowing the [ ... ] spelling, and while here, fix up the handling of
>> > a single, non-empty argument to comply with POSIX.
>> > 
>> > v2: update documentation, add a few more test cases.
>> > 
>> > CI is happy: https://github.com/u-boot/u-boot/pull/905
>> > 
>> > [...]
>> 
>> Applied to u-boot/next, thanks!
>> 
>> [1/4] cmd: test: allow using [ as alias for test
>>       commit: fc8bf9a984c118d551b3f93c66f1ae2733b9b588
>> [2/4] doc: test: document [ ] spelling of test
>>       commit: d44f61582947564991cce7501f2e5db0b29ebad6
>> [3/4] test: add tests for left-bracket alias for 'test' command
>>       commit: 6f9cc3310a764aaae4478b5a8a0c0cae3b2be4a1
>> [4/4] cmd: test: fix handling of single-argument form of test
>>       commit: 8b0619579b2282050e7fb0d92fbc645b79d18bae
>> -- 
>> Tom
>> 
>> 
> Hello,
>
> While preparing a patch series based on u-boot/next, I realised that 
> the bootflow on our module broke.
> I discovered that the issue was introduced with 
> commit 8b0619579b2 ("cmd: test: fix handling of single-argument form of test")
>
> This change breaks our boot script as it relies on the behaviour of test
> with unquoted empty expansions. For example:
>
> ```
> test -n ${m4boot} || env set m4boot ';'
> ```
> Is now `test -n`, as there are no quotation marks. It now returns 
> true, so the fallback assignment is skipped and it breaks our boot flow.
>
> Any ideas? I think that we will not be the only ones affected by 
> this once it's merged into master.

Urrgh, sorry about that. That snippet is arguably fragile and buggy, but
yes, similar code can exist elsewhere.

I don't really like it, but I suppose one could special-case the
single-argument case and interpret

  test -n

as

  test -n ""

with all other single-argument strings behaving as they do now. This
would need a separate test case and explicit documentation.  It's
probably quite rare that one would test a string for emptiness where a
possible non-empty value is exactly "-n", and since the single-argument
case hasn't really been supported in U-Boot until now, I don't think
such code really exists. Moreover, I don't think one should ever rely on
that single-argument behaviour anyway;

  test "$str"

should always be spelled

  test -n "$str"

Single-argument 'test -z' does not need special treatment, because
both 'test -z' and 'test -z ""' are true, but we could add the former as
a test case as well if we do implement the above.

Rasmus