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From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: net.unix
Subject: Re: question-- Bourne (and C) SHELL
Message-ID: <3082@brl-smoke.ARPA>
Date: Fri, 15-Aug-86 17:29:09 EDT
Article-I.D.: brl-smok.3082
Posted: Fri Aug 15 17:29:09 1986
Date-Received: Tue, 19-Aug-86 03:31:08 EDT
References: <1751@ittatc.ATC.ITT.UUCP> <7028@utzoo.UUCP> <150@humming.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 24

In article <150@humming.UUCP> arturo@humming.UUCP (Arturo Perez) writes:
>In  summary,  how can I take the logical NOT of a command's return value in
>the Bourne shell (which is God's gift to U**X :-)?

Here is how the .funcs function-definition file I source from my .profile
does it:

not(){	$*
	if [ $? -eq 0 ]
	then	return 1
	else	return 0
	fi
}

So I can then use this new "not" command as in:
	if not stuff ...
	then	whatever
	fi

Another more direct trick is:
	if stuff ...
	then	:
	else	whatever
	fi