Apticron is a great tool, it will automatically e-mail you an alert if you have outstanding packages that need upgrading on a *nix systems. Some useful tips to customise it are shown below.

These variables can be set in /etc/apticron/apticron.conf - The file is well commented. Here are a couple of quick more advancted examples.

Custom e-mail address:

CUSTOM_FROM="Server Updates <[email protected]>"

Custom System Name:

SYSTEM = "example.com"

To test apticron rather than waiting for the cron job to run the following from the terminal:

/usr/sbin/apticron