I think you could not start or end sl4a service from terminal, it's implemented with java and was started with the android's startService API.
If your mobile is rooted, you could call qpython's python Interpreter without start the qpython app, if your mobile is not rooted, you could not call do that for android's app security policy.
The handshake was generated by some random UUID function, so I think it's possible to get it by some special method.
: )