I've copied a folder of data from one linux server to another via a tarball.

The group ids (GIDs) don't match up on the two servers, so I now have files that look like

```
-rw-rw-r--   1 tim  1013   88 2008-11-14 10:18 config

```

There is a mixture of group ownerships in the folder, and I want to keep them owned by different groups on the same server, so I can't just use `chgrp -R`.

How do I change all files/folders with GID 1013 to another group, without affecting other files/folders?

Thanks