Then, next time you want to shuffle your music, simply run that command, and it will shuffle all of your music.
It doesn't work right. I can only use shuffler once after fresh reboot is done and no music has been played. Kindle music player has no "stop" button but just simple play/pause. So if any music is played before shuffling music collection (and paused or not) it just doesn't work. Kindle stops to play music at all (at the end of current track if on) and device restart is needed. Repeating shuffle causes the same so to use it again or to use music player I have to reboot kindle; not too convenient.