Python subprocess and user interaction

Question

I\'m working on a GUI front end in Python 2.6 and usually it\'s fairly simple: you use subprocess.call() or subprocess.Popen() to issue the command

Answer 1

Check out the subprocess manual. You have options with subprocess to be able to redirect the stdin, stdout, and stderr of the process you're calling to your own.

from subprocess import Popen, PIPE, STDOUT

p = Popen(['grep', 'f'], stdout=PIPE, stdin=PIPE, stderr=STDOUT)

grep_stdout = p.communicate(input='one\ntwo\nthree\nfour\nfive\nsix\n')[0]
print grep_stdout

You can also interact with a process line by line. Given this as prog.py:

import sys
print 'what is your name?'
sys.stdout.flush()
name = raw_input()
print 'your name is ' + name
sys.stdout.flush()

You can interact with it line by line via:

>>> from subprocess import Popen, PIPE, STDOUT
>>> p = Popen(['python', 'prog.py'], stdout=PIPE, stdin=PIPE, stderr=STDOUT)
>>> p.stdout.readline().rstrip()
'what is your name'
>>> p.communicate('mike')[0].rstrip()
'your name is mike'

EDIT: In python3, it needs to be 'mike'.encode().