SoundTracker is a music tracking tool for Unix / X11, which is similar in design to programs like FastTracker (DOS) and ProTracker (Amiga). Samples are lined up on tracks and patterns which are then arranged to create a song. Supported module formats are XM and MOD; the player code is taken from OpenCP. A basic sample recorder and editor is also included. SoundTracker is licensed under the GNU GPL.
One of the key advantages of the tracker system is the small file size of the modules. Each sample is only stored once and can be looped, faded, pitch shifted, etc. The track data is very small and the patterns can be repeated in any order to produce huge songs that come in at a few k in size.