Deleting modified files

[Thomas Poindessous]

Hi

I'm trying to do a backup of several servers which are almost  
identical. I want to have a "base" directory and one directory by  
server.

The base directory will have only the files which are identical on all  
the servers, and each server directory will have all of  the other  
files which are not in base directory.

So I'm trying to use rsync for :
- deleting files which are only in base (from previous backup) : -- 
ignore-existing --existing -delete server::slash/etc/ base/etc/
- updating server directory but avoiding to get files which are in  
base :  --compare-dest=$PWD/base/etc/ server::slash/etc/ server/etc/

But I'm still searching how to delete modified files on receiver side,  
I need it to purge base directory from each server.

I also have a problem with --compare-dest and --checksum because  
sometimes files are identical on each server but they have different  
modification time.

Maybe somebody has some examples to share :)

Thanks in advance.