Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!cs.utexas.edu!uunet!cbmvax!ag
From: ag@cbmvax.UUCP (Keith Gabryelski)
Newsgroups: comp.unix.questions
Subject: Re: How do I ask "if NOT" in shell?
Message-ID: <8243@cbmvax.UUCP>
Date: 24 Oct 89 02:17:32 GMT
References: <28381@shemp.CS.UCLA.EDU> <3787@solo6.cs.vu.nl>
Reply-To: ag@cbmvax.UUCP (Keith Gabryelski)
Organization: Commodore Technology, West Chester, PA
Lines: 31

In article <3787@solo6.cs.vu.nl> maart@cs.vu.nl (Maarten Litmaath) writes:
>kirkaas@oahu.cs.ucla.edu (paul kirkaas) writes:
>\How can one say "if not" in a shellscript; that is, execute the body of
>\the "then" only if the argument of "if" returns a non-zero exit status?

It is actually a toss up for me between:

>	if not command
>	then
>		command
>	fi
>
>...where `not' is defined as the following shell function/script:
>
>	${1+"$@"}
>	test $? != 0

and

	until command
	do
	    :				# do some stuff
	    break			# explict break
	done

Agreed that there should be a cleaner way.

Pax, Keith
-- 
 "It took no computation to dance to the rock 'n roll station" -- VU
  ag@cbmvax.commodore.com     Keith M. Gabryelski      ...!uunet!cbmvax!ag