Backupninja allows you to coordinate system backup by dropping a few simple configuration files into /etc/backup.d/. Most programs you might use for making backups don't have their own configuration file format. Backupninja provides a centralized way to configure and schedule many different backup utilities.
homeLANsecurity is a series of shell scripts for loading iptables firewall rules. The goal of these scripts is to provide an easy to manage framework for standard iptables rule sets. The scripts are well documented and are easily edited. It is primarily designed to operate on home or small office gateway Linux system, but the scripts can be easily adapted to protect an individual Linux server or workstation. homeLANsecurity's command set is written to support loading, clearing, saving, restoring, testing, and displaying of iptables rules. The configuration supports NAT, port forwarding of common services, TOS packet mangling, OpenVPN, Squid transparent proxy, IP address banning, adaptive banning, and connection tuning. Custom iptables rules are easily inserted without any editing of the scripts themselves.
Boolean Expression Solver is a commandline utility that generates a truth table for a given Boolean expression. It is written in Java, so it will run on any platform that has the Java runtime environment installed, but the makefile and shell-script included for convenience generally require *nix.
envbot is an advanced modular IRC bot coded in bash. Features include SSL, IPv6, modularity (with several good modules already), transport modules (including OpenSSL, GnuTLS, netcat, etc.), loading/unloading/reloading of modules at runtime, rehashing configuration at runtime, advanced access control, and much more.