from subprocess import Popen, PIPE
    p1 = Popen(["foo"], stdout=PIPE)
    p2 = Popen(["bar"], stdin=p1.stdout, stdout=PIPE)
    p1.stdout.close()  # Allow p1 to receive a SIGPIPE if p2 exits.
    output, _ = p2.communicate()

https://docs.python.org/3.5/library/subprocess.html#replacin...