How can I tell what model iDevice is plugged into my USB via Terminal?
For all it's worth, I have ran the command line in Terminal with a few devices.

iPhone 4: iPhone: Version: 3.20

iPad 2: iPad: Version: 2.10

I have a 3GS somewhere but I can't find right now. I'll edit my answer if/when I find it. 

My wife has a iPhone 4S and a friend has a 5, I will try to also update once I get to run it.