Why is Berkeley "head" a program?

[Larry Tepper]

I'm tempted to post this to net.bugs.4bsd...

Call me naive if you wish, but why is /usr/ucb/head a program
and not a shell script?  It was my understanding that with UNIX
you were supposed to build new tools based upon current ones,
and that the shell was also considered a programming language.
In addition, I foolishly thought that if a function is not used
FREQUENTLY, then the "overhead" of using a shell script was
considered acceptable.  Perhaps there are people out there who
are head heads??? (Ouch! 8-)

I believe the following shell script is equivalent to /usr/ucb/head.
It could even be 5 lines shorter if, when presented with several
files, you were willing to accept an extra newline at the start of
the first one.

: head -- give the first few lines of a stream
count=10
case $1 in
-[0-9]*)
	count=`echo $1 | sed s/-//`
	shift
	;;
esac
case $# in
0|1)	sed ${count}q $1
	exit $?
	;;
esac
: first file is special
sed "1i\\
==> $1 <==
${count}q" $1
shift
for f in $*
do
sed "1i\\
\\
==> $f <==
${count}q" $f
done
-- 
Violence is the last refuge of the incompetent.

{ihnp4 hao philabs sdcrdcf ucbvax!nbires}!stcvax!lat	Larry Tepper
Storage Technology, MD-3T, Louisville, CO 80028		303-673-5435