Here is a link to my Mac (maybe Linux?) CouchPotato update script:http://dl.dropbox.com/u/7831344/update_couch_potato.sh
1. wget and git installed (I used macports to install on my box, but there are other ways)
2. may need to chmod the permissions
3. change the settings to your own
4. exit the terminal after the update
You can add this as a cron job if you want to do it automatically
Tested on OS X 10.6.3
EDIT: I updated the script to v1.1. It will no longer try to parse the CouchPotato settings file, just hard code your settings in. This means it will probably work on Linux too, but I haven't tested it.