Ditto can also be useful for backup and restore since, AFAICT, it preserves file meta data. (Unlike rsync for example.)
`ditto` will also preserve resource forks, which is occasionally necessary for not breaking apps or installer pkgs. I've had to use it when doing a semi-automated deployment of some zipped-up software to a hundred or so Macs via bash over ARD. `ditto -xkv`