command line to turn system sound off (mute)

I just want to know how turn off and turn on the sound of my pc with command lines. As I am scheduling a CD to play at 6:00 AM I want make me sure that no sound will be played before this hour. It should be something like this: 1:00 AM $turn my sound mute 5:59 AM $enable sound again 6:00 AM $play CD I'm trying to learn somethin about Cron because Kcron doesn't work at my SuSE 8.0 distro (Kcron can open and be configured, but it doesn't execute the scheduled tasks) and build some bash files to turn on/off the pc sound. thanks for any help a.