Re: sed --in-place bug (updates mtime of file even if no changes are made)

[Eric Blake]

On 11/08/2011 02:32 PM, John Vanderpool wrote:
> --in-place shouldn't update the mtime of the file if the pattern doesn't
> match
> (i.e. no changes were made to file)

Why not?  Conceptually, 'sed --in-place' is short-hand for 'sed > temp,
mv temp original', since it is not possible to known a priori whether
the sed script will modify the input when generating the temporary file.

You're welcome to submit a patch if you think you can fix it, but right
now, I don't think sed should have to recognize whether the output is
identical to the input.  If you need mtime unchanged, then use sed to a
temporary file yourself, and compare the two files before deciding
whether to move the temporary file or keep the original.

-- 
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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