rwl@uvacs.UUCP (10/14/84)
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I've just started to play with shell scripts and had to say I totally agree
with Larry Tepper's complaint about the Berkeley 'head' program being binary
rather than just a shell script. I guess the 'software tools' concept hasn't
cought on completely...
Anyway, I tried Larry's sh script and found it generally satisfactory, but
it doesn't quite work right when you execute
cat big_file | head.sh
(where 'head.sh' is Larry's script, and 'big_file' contained ~ 30K characters).
I guess the reason is that 'sed' has to do buffering when you use the 'i'
command within it. Anyway, I thought I'd try my own version. For 0 or 1 file,
it exec's to 'sed' for the sake of speed rather than running 'sed' and exiting.
# head: print the first lines of a stream.
PATH=/bin
case $1 in
-[0-9]*) count=`echo $1 | sed 's/-//'` ; shift ;;
*) count=10
esac
case $# in
0|1) exec sed ${count}q $1 ;;
*) echo "==> $1 <==" ; sed ${count}q $1 ; shift
esac
for f in $*
do
echo "
==> $f <=="
sed ${count}q $f
done
I think this version is a little faster on the whole, and it avoids the
"Broken pipe" message that I get when I cat a large file through the former
version.
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Ray Lubinsky
University of Virginia, Dept. of Computer Science
uucp: decvax!mcnc!ncsu!uvacs!rwl
AT$T: (804) 924-7280
mail: ...get serious, who mails anything these days?thoth@tellab2.UUCP (Marcus Hall) (10/19/84)
In article <1571@uvacs.UUCP> rwl@uvacs.UUCP writes: > I think this version is a little faster on the whole, and it avoids the >"Broken pipe" message that I get when I cat a large file through the former >version. But the Berkeley 'head' program *DOES* give the "Broken pipe" message, so does this mean that this is no longer compatible? :-) marcus hall ..!ihnp4!tellab1!tellab2!thoth -- marcus hall ..!ihnp4!tellab1!tellab2!thoth
wls@astrovax.UUCP (William L. Sebok) (10/24/84)
"head" is used enough here to justify making it a C program. I really don't
see how one gains any clarity by replacing a perfectly good short C program
with a complicated shell script using sed. I think that the latter is much
harder to understand.
And also slower if any Unix zealots out there still care about performance.
--
Bill Sebok Princeton University, Astrophysics
{allegra,akgua,burl,cbosgd,decvax,ihnp4,noao,princeton,vax135}!astrovax!wls