git-am: head -1 is obsolete and doesn't work on some new systems

head -<n> was deprecated by POSIX, and as modern versions of coreutils
package don't support it at least one exports _POSIX2_VERSION=199209
it's fails on some systems.

head -n<n> is portable, but sed <n>q is even more.

Signed-off-by: Alejandro Mery <amery@geeks.cl>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-am.sh b/git-am.sh
index b48096e..2c517ed 100755 (executable)
--- a/git-am.sh
+++ b/git-am.sh
@@ -421,7 +421,7 @@ do
        else
            action=yes
        fi
-       FIRSTLINE=$(head -1 "$dotest/final-commit")
+       FIRSTLINE=$(sed 1q "$dotest/final-commit")
 
        if test $action = skip
        then