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From: friesen@psivax.UUCP (Stanley Friesen)
Newsgroups: net.bugs.4bsd
Subject: Re: slight problem with grep.
Message-ID: <995@psivax.UUCP>
Date: Wed, 5-Feb-86 13:25:31 EST
Article-I.D.: psivax.995
Posted: Wed Feb  5 13:25:31 1986
Date-Received: Fri, 7-Feb-86 21:03:47 EST
References: <9299@ritcv.UUCP> <140@calma.UUCP>
Reply-To: friesen@psivax.UUCP (Stanley Friesen)
Distribution: net
Organization: Pacesetter Systems Inc., Sylmar, CA
Lines: 24
Keywords: grep

In article <140@calma.UUCP> radzy@calma.UUCP (Tim Radzykewycz) writes:
>
>Note that this will only happen if 'zzzz' is an existing file.  If
>either of the following situations occur, there won't be a problem:
>       grep write * > AAAA             <- AAAA doesn't contain 'write'
>       rm zzzz ; grep write * > zzzz
>
>In the first situation, the file 'AAAA' is searched first.
>In the second situation, the '*' doesn't match the file 'zzzz',
>so grep never even opens it.
>--
        Actually, the second form *does not* work. The shell performs
I/O redirection *before* filemname substitution, so the file 'zzzz'
does exist and *is* included in the expansion, and grep *will* open
it. At least this is true for csh, I tried it(in a harmless way using
echo rather than grep). The first one will work because when grep
scans AAAA it will be totally empty, due to the shell opening it for
writing.
--

                                Sarima (Stanley Friesen)

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