[PATCH 5.4 205/214] kheaders: remove unneeded cat command piped to head / tail

Greg Kroah-Hartman
2020-09-01T16:14:44Z

From: Masahiro Yamada <yamada.masahiro@socionext.com>

commit 9a066357184485784f782719093ff804d05b85db upstream.

The 'head' and 'tail' commands can take a file path directly.
So, you do not need to run 'cat'.

cat kernel/kheaders.md5 | head -1

... is equivalent to:

head -1 kernel/kheaders.md5

and the latter saves forking one process.

While I was here, I replaced 'head -1' with 'head -n 1'.

I also replaced '==' with '=' since we do not have a good reason to
use the bashism.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/gen_kheaders.sh | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/kernel/gen_kheaders.sh
+++ b/kernel/gen_kheaders.sh
@@ -41,10 +41,10 @@ obj_files_md5="$(find $dir_list -name "*
this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
if [ -f kernel/kheaders.md5 ] &&
- [ "$(cat kernel/kheaders.md5|head -1)" == "$src_files_md5" ] &&
- [ "$(cat kernel/kheaders.md5|head -2|tail -1)" == "$obj_files_md5" ] &&
- [ "$(cat kernel/kheaders.md5|head -3|tail -1)" == "$this_file_md5" ] &&
- [ "$(cat kernel/kheaders.md5|tail -1)" == "$tarfile_md5" ]; then
+ [ "$(head -n 1 kernel/kheaders.md5)" = "$src_files_md5" ] &&
+ [ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$obj_files_md5" ] &&
+ [ "$(head -n 3 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
+ [ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
exit
fi