A backup script using rsync, and its example configuration file. I put the backup script in ~/bin/jbackup, or /usr/sbin/jbackup, and the config file in /etc/jbackup, or .jbackup.
Warning: I inserted a poor check for the mountpoint at line 84 in an earlier version, and accidentally ran this script without the backup disk mounted. This copied my /home partition to my root partition and caused some problems. My hard drive was full, but I couldn't find out why because mounting the disk on /mnt/backup covered up the disk usage. Luckily someone over at Linuxquestions suggested this might be the problem. I have updated the check for the mountpoint, however let me know if you still have the same problem.