aircrack-ng is a set of tools for auditing wireless networks. It's an enhanced/reborn version of aircrack. It consists of airodump (an 802.11 packet capture program), aireplay (an 802.11 packet injection program), aircrack (static WEP and WPA-PSK cracking), airdecap (decrypts WEP/WPA capture files), and some tools to handle capture files (merge, convert, etc.).
Alarm Pinger (apinger) is a little tool which monitors various IP devices by simple ICMP echo requests. Unlike most Perl or shell script tools, it does not spawn processes or use much CPU time, and is ideal for when one wants continuous monitoring and fast response upon target failure. It is written in C and supports both IPv4 and IPv6.
Alert Manager allows you to monitor the output (exit status or text) of any system command and take action when a command fails or succeeds. It was created to handle all alert commands (emailing, paging, etc.) for a production environment in which it is not permissible to lose a single message. It has a very flexible configuration file that allows the creation of "alert chains", chains of alerts, each with its own alert command, fallback command, success command, and other options. It has a method for passing messages (alert text) from the commandline to the various alert commands defined in the configuration file.