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 <firstname.lastname@example.org>
Signed-off-by: Junio C Hamano <email@example.com>