rsync can be used locally or over the network. It supports ssh, for secure remote differential backups.
General usage:rsync -e ssh -avz src_path username@hostname.com:dst_path
e.g.:rsync -e ssh -avz /etc/ root@myserver.com:/etc/
To delete files that are on the destination system but no longer on the source system, use the --delete option:
e.g.:rsync -e ssh -avz --delete /lib/ root@myserver.com:/lib/
Here's the full meal deal for doing a total system backup. This will completely duplicate one system onto another, over the Internet. Make sure the hardware, boot devices, etc are the same or you're in for trouble:rsync -e ssh -avz --stats --progress --delete-after --exclude-from=/root/rsync-exclude / root@myserver.com:/
Note that "/root/rsync-exclude" should include things like:dev/tmp/proc/var/lock/var/run/
You can use rsync to show differences between two directories without changing anything. In the following example, your /home/myuser is compared with the same folder on computer target:rsync -e ssh -avz --delete --dry-run /home/myuser root@target:/home
This comparison only considers timestamps and file sizes. For comparing directories based on content, use other programs, e.g. krusader.