kheaders: remove unneeded 'cat' command piped to 'head' / 'tail'

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>

diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh
index 5a0fc0b0403a6c46cd41a0b73a07846eb118a016..b8054b0d50105ace858a31c03c7d2255c5b3031c 100755 (executable)
--- a/kernel/gen_kheaders.sh
+++ b/kernel/gen_kheaders.sh
@@ -41,10 +41,10 @@ obj_files_md5="$(find $dir_list -name "*.h"                    |
 this_file_md5="$(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