GNU bug report logs - #12366
[gnu-prog-discuss] Writing unwritable files

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Package: coreutils;

Reported by: Paolo Bonzini <bonzini <at> gnu.org>

Date: Thu, 6 Sep 2012 12:14:01 UTC

Severity: normal

Done: Jim Meyering <meyering <at> hx.meyering.net>

Bug is archived. No further changes may be made.

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Message #35 received at 12366 <at> debbugs.gnu.org (full text, mbox):

From: Bob Proulx <bob <at> proulx.com>
To: gnu-prog-discuss <at> gnu.org, John Darrington <john <at> darrington.wattle.id.au>,
	12366 <at> debbugs.gnu.org
Subject: Re: bug#12366: [gnu-prog-discuss] Writing unwritable files
Date: Thu, 6 Sep 2012 11:12:25 -0600

Paul Eggert wrote:
> >> If some other process is writing F
> >> while I run 'sed -i F', F is not replaced atomically.
> 
> > How not so?
> 
> For example:
> 
> echo ac >f
> sed -i 's/a/b/' f &
> sed -i 's/c/d/' f
> wait
> cat f
> 
> If 'sed' were truly atomic, then the output of this would
> always be 'bd'.  But it's not.

The file replacement is atomic.  The reading of the file is not.

Bob
This bug report was last modified 12 years and 232 days ago.

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