MavProxy -- having trouble executing commands at command line

Thanks for your consideration, I have searched and searched but can’t find an answer to this: Commands entered via the command line of Mavproxy don’t seem to work at all.
I have set up SITL on both a mac and PC and installed Mavproxy on both… I am able to set up multiple links via UDP and TCP so everything seems to work. The only thing is when i try to change modes for instance from the command line there seems to be no effect. I am able to change modes using Tower or Mission Planner an see the results on the SITL…