Monitoring other operations
Nagios also offers plugins for many other operations that are common to daily system monitoring and activities; this section covers only a few of them. It is recommended that you look for the remaining commands in both the Nagios Plugins package as well as on the Nagios Exchange website.
Checking for updates with APT
Many Linux distributions use Advanced Packaging Tool (APT) for handling package management (refer to http://wiki.debian.org/Apt). This tool is used by default on Debian and its derivatives such as Ubuntu.
It allows the handling of upgrades and download of packages. It also allows the synchronization of package lists from one or more remote sources.
Nagios provides a plugin that allows you to monitor if any upgrades are available and/or perform upgrades automatically. The syntax and the description of the options are as follows:
check_apt [-d|-u|-U [<opts>]] [-n] [-t timeout]
[-i <regex>] [-e <regex>] [-c <regex...