| Message ID | 20191008120556.4263-1-yamada.masahiro@socionext.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] kheaders: remove unneeded 'cat' command piped to 'head' / 'tail' | expand |
On Tue, Oct 8, 2019 at 9:06 PM Masahiro Yamada <yamada.masahiro@socionext.com> wrote: > > 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> > --- Series, applied to linux-kbuild. > > kernel/gen_kheaders.sh | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh > index aff79e461fc9..8aa6d3c37ba7 100755 > --- 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)" = "$tarfile_md5" ]; then > exit > fi > > -- > 2.17.1 >
diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh index aff79e461fc9..8aa6d3c37ba7 100755 --- a/kernel/gen_kheaders.sh +++ b/kernel/gen_kheaders.sh @@ -41,10 +41,10 @@ obj_files_md5="$(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
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> --- kernel/gen_kheaders.sh | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)