Re: [PATCH] Add new option --in-place (original) (raw)

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From: Pádraig Brady
Subject: Re: [PATCH] Add new option --in-place
Date: Thu, 25 Mar 2010 11:30:45 +0000
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On 24/03/10 12:15, Pádraig Brady wrote:

Also I noticed that mv -b ./file.tmp ./file is not atomic because the renames are done like: rename(file,bak); rename(tmp,file);

I summarized the issues involved with replacing files and it was surprisingly popular: http://www.reddit.com/r/programming/comments/bhnab/replacing_a_file_on_unix_is_hard/

It was indirectly suggested there to use hardlinks for atomic backups, which I've amended the attached script to do. Other changes include falling back to cp -a if --attributes-only is not supported, and correctly removing all temp files.

I wonder should mv -b (and sed -i) use the ln method to try to be atomic and then fall back to the double rename? I'll look into it at some stage.

cheers, Pádraig.

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