efficiently synchronizing source and destination

[Christian Hack]

> I have two fat32 formatted external drives (on the localhost) that
> need sync'ing. Each of the drives contain different files. The end
> result I'm looking for is two identical disks.
> 
> My question is whether or not I can encapsulate this process in a one
> liner with rsync or if i need to make two independent calls to rsync
> as follows:
> 
> rsync -av /path/to/source /path/to/dest && rsync -av /path/to/dest
> /path/to/source
> 
> In the situation above, the dest has files that do not exist on the
> source, hence the second call to rsync...
> 

This will only work if the files on each disk are not common. Otherwise if
you update a file on dest it will get overwritten by the first sync from
source.

CH