rsync

# on-the-fly backup (backup whole running system)
rsync -av --delete --numeric-ids --exclude=dev/* --exclude=proc/* --exclude=sys/* --exclude=tmp/* --exclude=media/* root@example.com:/ .

# limit bandwith to 2 mbit/s
rsync --bwlimit=2000 --delete -avz root@www.example.com:/ /media/backup/www.example.com/$(date -I)/

# specify SSH key and configuration
sudo rsync -av \
-e "ssh -i /home/foo/.ssh/id_rsa -F /home/foo/.ssh/config" \
--delete \
--numeric-ids \
-av \
/from/dir/ root@192.168.0.1:/to/dir