[PD] Linux: changing sound card params from patch, sending OS commands

I'm using Pd as part of the engine for an interactive art project. The setup is an old PII laptop running xubuntu Dapper. I'm stuck on a few things:

1. It's a long story but the bottom line is that it appears that I have to use this crappy computer as well as its less-than-steller internal sound card, and that the internal sound card or driver has some sort of bug which requires me to switch to ALSA *after* starting Pd. Everything else produces no sound. And OSS is completely inoperative. So is there a way I can do this in a patch? (The sound card is a Yamaha OPL3-SA23 BTW.)
2. I'd like Pd to be able to send commands to the OS such as shutdown -h "now" when the gallery closes each evening. Is there a way to send such commands from a patch? The only thing I could think to do is send a message to a Python script using sockets....seems rather clumsy.

Thanks,

-John