Making python run a file in command line, input something, wait and then input something again

Question

In python, I wanted to do the following: I have a command-line program that requires user to enter input step by step & wait in between to get the result. Now, I want to automate this process using python.

The process will be something like:

run myProgram.exe in commandline
enter command 1
wait for command 1 to run & finish (takes ~5 minutes)
enter command 2 ...

is there a way to simulate this process in python? I knew that we can run a program & pass in command line parameters using os.open() or subprocess. But those are a one-off thing.

Thanks

Facundo Casco · Accepted Answer · 2011-11-16 15:46:07Z

3

You can use subprocess module and Popen.communicate() to send data to the process stdin

EDIT:

You are right, he should use stdin.write to send data, something like this:

#!/usr/bin/env python

import subprocess
import time

print 'Launching new process...'
p = subprocess.Popen(['python', 'so1.py'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)

print 'Sending "something"...'
p.stdin.write('something\n')

print 'Waiting 30s...'
time.sleep(30)

print 'Sending "done"...'
p.stdin.write('done\n')

p.communicate()
print '=o='

edited Nov 16, 2011 at 15:46

answered Nov 15, 2011 at 22:54

Facundo Casco

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1 Comment

slowdog Over a year ago

Popen.communicate blocks until the process terminates, so the "enter command 2" part won't be possible.

slowdog · Accepted Answer · 2011-11-15 23:03:01Z

2

On Unix, or with cygwin python on Windows, the pexpect module can automate interactive programs.

See the examples here. You'll want to pass a longer-than-default timeout argument to expect() for the part that takes five minutes.

answered Nov 15, 2011 at 23:03

slowdog

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