I have been looking for a way to mirror my home folder on my Macbook with a linux server (nslu2 with Unslung Linux in this case), this article describes how to do that with tools already available in Leopard.

"Home Server v2" by Montini

I assume you have a valid SSH login on the server, I simply enabled my account on the NSLU2 and assigned the proper home and shell values to it. I also assume both computers have an working installation of rsync (run rsync --version to check)

For automatic, password-less logins, first we need to generate keys for SSH, if you have them already, skip this section. Run this command on your local computer:
$ ssh-keygen -d

Now copy your public key into ~/.ssh/authorized_keys2 on the server. If this file already exists on the server, you will have to edit it, if it does not (e.g. your account is fresh) first create the ~/.ssh directory on your server (mkdir ~/.ssh), then execute this command on your local computer:
$ scp ~/.ssh/id_dsa.pub yourname@yourserver:.ssh/authorized_keys2

Before we can start mirroring your home folder, we have to create a list of files we don't want to synchronize, this are the contents of my ~/.rsync/exclude file:

- .DS_Store
- Virtual Machines.localized
- Library/Mail Downloads
- Library/Caches
- Downloads/
- Applications/
- Books
- anthill_cache
- .Trash
- .localized

That's it, now all you need to do is to adapt this command to your environment,  run it and wait...
$ rsync -avzP --exclude-from=/Users/me/.rsync/exclude -4 --delete -e 'ssh -ax' ~/ you@yourserver:~/Backups/mymacbook/

you can also create a shell script so you don't need to remember the command everytime:
$ echo "rsync -avzP --exclude-from=/Users/me/.rsync/exclude -4 --delete -e 'ssh -ax' ~/ you@yourserver:~/Backups/mymacbook/" > ~/remotebackup; chmod +x ~/remotebackup
You can start the backup by executing ~/remotebackup