How do I write to a Python subprocess' stdin?

Question

I\'m trying to write a Python script that starts a subprocess, and writes to the subprocess stdin. I\'d also like to be able to determine an action to be taken if the subpro

Answer 1

It might be better to use communicate:

from subprocess import Popen, PIPE, STDOUT
p = Popen(['myapp'], stdout=PIPE, stdin=PIPE, stderr=PIPE)
stdout_data = p.communicate(input='data_to_write')[0]

"Better", because of this warning:

Use communicate() rather than .stdin.write, .stdout.read or .stderr.read to avoid deadlocks due to any of the other OS pipe buffers filling up and blocking the child process.