MacOSX::File is a perl module that allows you to get and set HFS file attributes. And psync is a perl script that uses MacOSX::File to implement inclemental backup and restore.

The hard drive in my Macbook Pro died, and I could not work for a week. That sucked. So I got a backup firewire drive. psync creates a bootable backup onto my firewire drive. Even if my own hard drive dies, I can boot from the backup and then pull the new source code from svn. I only have to update as often as I upgrade libraries to keep coding with a dead drive, with no downtime.

Its uncommented perl, which is a downside.

MacOSX::File and psync: Bootable Firewire Drive Backup