Listing Changed Files Without Two Copies?

[Jon Watson]

Hi All,

I am aware that rsync can be run to just list the files that have 
changed between the source and destination. I would like to capitalize 
on that feature to monitor some development that is going on in order to 
get a complete list of files that have been changed on a server.

I realize that I can create an initial rsync of the files to some other 
location and then sometime later run rsync in list only mode against 
that initial repository to find out what files have changed.

I also realize that there are revisioning tools out there but they are 
complete overkill for this particular issue.

What I am curious about is if there is a way to achieve this without 
maintaining two copies of the files. Is there any way to run rsync 
against a fileset where rsync will produce a checksum or something for 
those files and can then later determine what files have changed without 
maintaining a second copy of those files?

I realize rsync is primarily a backup tool (and a great one!) and this 
probably falls outside of its purview.

Any tips/tricks are welcome.

Thanks,

Jon