AIDE (Advanced Intrusion Detection Environment) is a file and directory integrity checker. It creates a database from the regular expression rules that it finds from the config file. Once this database is initialized it can be used to verify the integrity of the files. Several message digest algorithms are used. All of the usual file attributes can also be checked for inconsistencies.
Angel is a simple yet useful tool to monitor the services on your network. Technically speaking, it's a Perl program that runs every 'n' minutes (usually fired from your cron) and calls different perl subprograms (referred to as "plugins" from now on) to do the actual testing. It will then generate an HTML table containing the status of your network.
Angst is an active sniffer, based on libpcap and libnet. It dumps into a file the payload of all the TCP packets received on the specified ports. It implements two methods for active sniffing. Angst is able to monitor ARP requests, and after enabling IP forwarding on the local host, it sends ARP replies mapping all IPs to the local MAC address. Also, it can flood the local network with random MAC addresses (like macof), causing switches to send packets to all ports.
Anteater is a log analyser for MTA logfiles (such as those produced by sendmail and postfix). The tool is written in 100% C++ and is very easy to customize. Input, output, and the analysis are modular class objects with a clear interface. Currently, there are modules for reading the syslog format of sendmail and postfix that do up to eight useful analyses and write the result in plain ASCII or HTML, to stdout or to files.
Apmiser is a daemon that monitors the CPU usage patterns of your laptop and automatically switches between power-saving mode (in which the CPU is underclocked) and normal mode, depending on whether it thinks you will need the extra CPU speed. This lets you leave your laptop in it's power-saving state without having to suffer from poor performance when you need to perform a CPU-intensive task. Apmiser currently only supports IBM Thinkpads via tpctl, but support can be easily added for any laptop that supports switching power-saving modes programmatically.
Aps is a small tool for analyzing network traffic. It prints out a great deal of information about the relevant protocols including TCP, UDP, ARP, and ICMP. It allows you to filter IP addresses, hardware addresses, ports, and specific protocols. It comes with a little GTK-GUI displaying packet counters for each protocol.
This is a Linux driver for the Artec AS6E scanner. It scans on all available hardware resolutions in color, greyscale, and lineart, and functions in EPP, PS/2, and SPP parallel port modes. It can be used as a stand-alone program from the command line, or through the SANE (Scanner Access Now Easy) project's software.
asapm is an AfterStep look & feel Advanced Power Management (APM) monitor for laptop and notebook PCs running Linux or FreeBSD/NetBSD/OpenBSD and X Windows. It displays charge left in the battery, the time left to the total discharge of the battery, computer is connected to the mains or is working on a battery and the battery status high/low/critical.