Prevent shutdown of server while clients connected

Hello all. I'm new to this forum and was hoping to get some advice regarding shell script code to check if LMS is 'serving' content and to prevent shutdown if that's the case.

I have a mediapc running mythtv and xbmc etc on an unbuntu machine. It's a bit of a hog, so I have it set to standby when not in use by recordings or streaming to front end for living room tv etc. I have no logitech hardware, but am using various software players on wireless hardware throughout my house. I'm currently having to ssh into the server as I have a condition in mythfrontend script that waits for ssh sessions to finish before allowing standby. THen when done streaming audio, I have to remember to stop that so that the machine can go to sleep.

I'd really like to avoid all that (especially as without the ssh session from the computer, there's no way of keeping the server on if I want to stream remotely to my phone etc - it will time out after a few minutes.)

Does anyone know of commands or code that would appear in running proccesses that I can use for a script to watch for? I've looked myself and the various processes that show up are related to preference file and plugins - nothing that seems to change or suggest a difference when a player is connected and streaming audio.

Thanks in advance for any help!