Date: Fri, 31 May 2002 09:47:20 -0700 From: Matthew Hunt <mph@astro.caltech.edu> To: j mckitrick <jcm@FreeBSD-uk.eu.org> Cc: Benoit Lacherez <blacherez@ac-bordeaux.fr>, freebsd-questions@FreeBSD.ORG Subject: Re: Why does 'sed' delete my input file? Message-ID: <20020531094720.C34758@wopr.caltech.edu> In-Reply-To: <20020531132211.A29199@dogma.freebsd-uk.eu.org>; from jcm@FreeBSD-uk.eu.org on Fri, May 31, 2002 at 01:22:11PM %2B0100 References: <20020531130029.B28925@dogma.freebsd-uk.eu.org> <20020531141421.A72043@bisclavret.iris33.ac-bordeaux.f> <20020531132211.A29199@dogma.freebsd-uk.eu.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, May 31, 2002 at 01:22:11PM +0100, j mckitrick wrote: > | cat file1 | sed 's/foo/bar/g' > file1 > > Perfect! I don't think that's guaranteed to work at all. There's no assurance that cat will have read then entire contents of file1 before the shell opens it for writing. wopr:~/tmp$ wc -l blah 164925 blah wopr:~/tmp$ ls -l blah -rw------- 1 mph mph - 6807485 May 31 09:42 blah wopr:~/tmp$ cat blah | sed 's/foo/bar/g' > blah wopr:~/tmp$ ls -l blah -rw------- 1 mph mph - 0 May 31 09:42 blah My shell is bash. -- Matthew Hunt <mph@astro.caltech.edu> * Eight lanes of shimmering cement from http://www.pobox.com/~mph/ * here to Pasadena! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020531094720.C34758>