Using subprocess with select and pty hangs when capturing output

Question

I\'m trying to write a python program that is able to interact with other programs. That means sending stdin and receiving stdout data. I cannot use pexpect (although it definit

Answer 1

From what I understand, you do not need to use pty. runner.py can be modified as

import subprocess
import sys

def main():
        process = subprocess.Popen(['python', 'outputter.py'],
                        stdin=subprocess.PIPE,
                        stdout=subprocess.PIPE, stderr=subprocess.PIPE)

        while process.poll() is None:
                output = process.stdout.readline()
                sys.stdout.write(output)
                sys.stdout.flush()
        print "**ALL COMPLETED**"

if __name__ == '__main__':
        main()

process.stdout.read(1) can be used instead of process.stdout.readline() for real-time output per character from the subprocess.

Note: If you do not require real-time output from the subprocess, use Popen.communicate to avoid the polling loop.