spinner sends small packets (null packets or a fancy ASCII spin fan with motion) to keep a link up.

The Mole is an automatic SQL Injection exploitation tool. Only by providing a vulnerable URL and a valid string on the site it can detect the injection and exploit it, either by using the union technique or a boolean query based technique.

xless allows you to view information in an X window. It allows filename (or multiple filenames) arguments, or input via STDIN. It can print the current buffer and do regular expression searches.

SpamBayes uses a different set of algorithm to most statistical spam filters, which enables to dramatically lower the number of legitimate mail classified as spam, through the introduction of an 'unsure' category.

Plait (pronounced "play") is a command-line jukebox and music player front end. It understands brief, easy to type queries that pick a single song, mix queries that combine works from multiple artists, stream queries that find Shoutcast radio streams, and everything in between.

Despite the NP completeness of the satisfiabilty problem of Boolean formulas (SAT), SAT solvers are often able to decide this problem in a reasonable time frame. As all other NP complete problems are reducible to SAT, the solvers have become a general purpose tool for this class of problems.