Daniel Arbuckle's Mastering Python

Using the Popen subprocess

At the cost of a bit more complexity, the Popen constructor accepts the same list of program and command-line arguments that the call functions do and a very large number of optional keyword arguments, including universal_newlines.

We're going to focus on a particular use of the Popen constructor that is useful, but goes beyond what we can achieve using one of the call functions. We're going to see how to run a program in the background while our own code is also running, and send and receive data between the two programs.