You're listening for two file descriptor events, so you need some sort of event loop. select can do it but it's low-level; and since there can be only one event

You're listening for two file descriptor events, so you need some sort of event loop. select can do it but it's low-level; and since there can be only one event loop per program, your choices are frameworks and not simply libraries. Here's a way to do it with Twisted (docs here: http://twistedmatrix.com/documents/current/core/howto/process.html http://twistedmatrix.com/documents/current/core/howto/proces... ): from twisted.internet import reactor, protocol class PrintAndLogProtocol(protocol.ProcessProtocol): def outReceived(self, data): # print and log errReceived = outReceived reactor.spawnProcess(PrintAndLogProtocol(), '/path/to/exe', ['exe', 'arg1', 'arg2']) reactor.run()