Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!ucbcad!scheme.Berkeley.EDU!sarge
From: sarge@scheme.Berkeley.EDU (Steven Sargent)
Newsgroups: comp.lang.c
Subject: Re: exit(-1), 0 is sometimes magic
Keywords: exit, zero, flaming
Message-ID: <2220@ucbcad.berkeley.edu>
Date: 22 Jan 88 02:28:09 GMT
References: <1234@nmtsun.nmt.edu> <502@cresswell.quintus.UUCP> <6935@brl-smoke.ARPA> <1179@wjvax.UUCP> <2305@bloom-beacon.MIT.EDU>
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The UNIX shells absolutely enforce the 0 vs. nonzero exit status
distinction.

1. The usages
	(Shell)		if cmdlist; then stuff; else stuff; fi
	(csh)		if ({cmd}) then stuff; else stuff; endif
along with their loop analogues, make the decision based on exit status
of cmd (or of the last command in cmdlist).

2. The Shell's operators && and || also work this way, i.e., in
	foo && bar
bar is executed only if foo exits happily.

3. The Shell has a command-line option (-e) that causes a script to
exit whenever a command exits nonzeroly.

All this (and more, I'm sure; but csh is of less interest to me in
this context) is available in the relevant manual pages.

S.