The traditional way back when everything was UNIX was to use cron to make a tar archive for backup; You could actually make Tar output into segments (I once backed up quake ii onto floppies that way -- over a hundred) of course if you wanted to burn them to CDs which you would it would be a LOT more complicated, since CD burning is not at all the same as tape (the T in tar) or floppies but I'm sure there is a shell script out there that will create 600MB tar files, turn them to isos and burn them to disk.
You could also mean back up your commands in bash. Check your directory with an ls -a for a file called .bash_history. It goes back 50 commands so the last one is ls -a. Obviously you can periodically back that up.
And ext3 is a journalling file system. I've never dug into the journal though.