There's nothing inherent about SSH that will keep you from running more than one command at a time. But calling ssh with a command executes the command and then exits, I'm guessing that's what you are doing when you call the perl command, so the connection is gone by the time you try to call the getOSType function in the "combined script".

Since getOSType and getPrompt aren't provided above, all we can do is guess at what's going on, which makes the probability of getting helpful answers drop close to zero.

-Scott