rsync to sync time without attempting to modify the content

Wayne Davison wayned at
Sun May 19 17:19:11 MDT 2013

On Tue, Apr 2, 2013 at 12:07 PM, Brice Rebsamen <brice.rebsamen at>wrote:

> So what I want, is to be able to compare files this way:
> if the file does not exist at the destination, then transfer it with
> timestamps (rsync -t)
> otherwise:
>     if timestamps and sizes are different:
>         if md5sums match
>             if the source time stamp is earlier than the destination
> timestamp
>                 update the timestamp of the destination
>         otherwise report (in a log file or something so that I can come
> back to those later)

You can use rsync to help with that, but it won't do it for you.  For
instance, the first part can be done by specifying --ignore-existing (so
that rsync just copies in missing files).  You could then get a list of
files that differ in their timestamp by running a --dry-run with
--itemize-changes.  If you use --checksum, it will differentiate
between identical files and those that are different, but it will take a
huge amount of time to checksum all files.  Instead, you may want to just
have rsync list all the files that differ by time and you then put them
into a --files-from file for rsync to check via --dry-run and --checksum.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the rsync mailing list