Python: How to interrupt raw_input() in other thread

You could just make the sending thread daemonic:

send_thread = SendThread()  # Assuming this inherits from threading.Thread
send_thread.daemon = True  # This must be called before you call start()

The Python interpreter won't be blocked from exiting if the only threads left running are daemons. So, if the only thread left is send_thread, your program will exit, even if you're blocked on raw_input.

Note that this will terminate the sending thread abruptly, no matter what its doing. This could be dangerous if it accesses external resources that need to be cleaned up properly or shouldn't be interrupted (like writing to a file, for example). If you're doing anything like that, protect it with a threading.Lock, and only call sys.exit() from the receiving thread if you can acquire that same Lock.