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From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.questions
Subject: Re: What's the return status of a pipeline???
Keywords: lpr,pipe,filter,status
Message-ID: <17442@mimsy.UUCP>
Date: 11 May 89 11:25:47 GMT
References: <186@marvin.moncam.co.uk>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 30

(The exit status of a pipeline is supposed to be the exit status of the
last process in the pipeline.  4BSD sh does not always get this right.)

In article <186@marvin.moncam.co.uk> harry@moncam.co.uk
(Jangling Neck Nipper) writes:
[csh script; all but the important part deleted]
>onintr quit
>$BIN/psfilter -b $* | $BIN/lwriter -pI "$LWRITER" $* >>& $acct
>quit:
>set printer_status = $status

This will always set printer_status to 0.  Let us hear it for csh
`design':  the label `quit' succeeds, wiping out the exit status
from the pipeline above.

See:

	% (exit 1)
	% echo $status
	1
	% (exit 1)
	% foo:
	% echo $status
	0
	%

Moral: never try to use csh for shell scripts.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris