LilyPond is a music engraving program, devoted to producing the highest-quality sheet music possible. It brings the aesthetics of traditionally engraved music to computer printouts. LilyPond is free software and part of the GNU Project.
Denemo is a free music notation program for GNU/Linux, Mac OSX and Windows that lets you rapidly enter notation which it typesets using the LilyPond music engraver. Music can be typed in at the PC-Keyboard, played in via MIDI controller, or input acoustically into a microphone plugged into your computer’s soundcard.
Rosegarden is a music composition and editing environment based around a MIDI sequencer that features a rich understanding of music notation and includes basic support for digital audio. It’s an easy-to-learn, attractive Linux application that is ideal for composers, musicians, music students and small studios or home recording environments.
Impro-Visor (short for “Improvisation Advisor”) is a music notation program designed to help jazz musicians compose and hear solos similar to ones that might be improvised. The objective is to improve understanding of solo construction and tune chord changes. There are other, secondary, things it can do, such as improvise on its own. It has also been used for transcription. Because rhythm-section (e.g. piano, bass, drums) accompaniment is automatically generated from chords, Impro-Visor can be used as a play-along device. Now having a wider array of accompaniment styles, its use is not limited to jazz./blockquote>