I have a VPS hosted somewhere running Ubuntu 10.04. How do I know when to patch the system? Is there a notification system analogous to, for example, Mac OS or Windows warning me (through email) to apply updates?
Sends an e-mail daily with details of required updates, perfect for servers.
You could use a simple cronjob to notify yourself about updates. Depending on the distribution you use, the package-manager will show you the available patches.
On ubuntu you could create a script like this:
#!/bin/bash aptitude update >/dev/null aptitude dist-upgrade -s
You should make sure that you get the cronjob emails. Run this script once a week via cron, and you should receive a mail with a list of available updates.