IIf you are looking for a music composition and editing tool runs on linux operation system,Rosegarden is your best choice.

Rosegarden is an easy-to-learn, attractive application that runs on Linux, ideal for composers, musicians, music students, and small studio or home recording environments.

Download Rosegarden:http://www.rosegardenmusic.com/getting/
See more about Rosegarden:http://www.rosegardenmusic.com/