1. Does either aplay or play-sound accept a command line argument to specify the volume?

2. Is the source code for aplay and/or play-sound available somewhere?

3. Are there other command line programs which play an audio file, & is the source code available?

4. aplay lists its arguments when invoked with --h, but play-sound does not. However, play-sound when used does return a message about the volume ("vol -0.00000") which seems to indicate that playback volume might be configurable. Is there some reference somewhere which lists command line programs like play-sound which are available on the N900 (I'm assuming as a part of Maemo) which details their function, arguments, etc. ?