Python subprocess get child's output

Question

Possible Duplicates:
How to get output from subprocess.Popen()
Retrieving the output of subprocess.call()

Here is my question. I have an executable called device_console. The device_console provides a command line interface to a device. In device_console, four commands can be run: status, list, clear and exit. Each command produces an output. As an example:

[asdfgf@localhost ~]$ device_console

device_console> list

File A

File B

device_console> status
Status: OK

device_console> clear
All files cleared

device_console> list
device_console> exit

[asdfgf@localhost ~]$

As part of testing, I want to get the output of each command. I want to use Python for it. I am looking at Python's subprocess, but somehow I am unable to put them together. Can you please help?

Duplicate of all of these: http://stackoverflow.com/search?q=%5Bpython%5D+subprocess+output. Specifically, http://stackoverflow.com/questions/1388753/how-to-get-output-from-subprocess-popen as just one of many exact duplicates. — S.Lott, Feb 09 '10 at 11:19

Corey Goldberg · Answer 1 · 2010-02-09T01:49:12.113

2

it sounds like you want something more like 'Expect'.

check out Pexpect

"Pexpect is a pure Python module that makes Python a better tool for controlling and automating other programs. Pexpect is similar to the Don Libes Expect system, but Pexpect as a different interface that is easier to understand. Pexpect is basically a pattern matching system. It runs programs and watches output. When output matches a given pattern Pexpect can respond as if a human were typing responses."

edited Feb 09 '10 at 01:49

answered Feb 09 '10 at 01:37

Corey Goldberg

59,062
28
129
143

Thanks. I will look into Pexpect too. – innvtt Feb 09 '10 at 14:23

score 2 · Answer 2 · answered Feb 09 '10 at 01:46

Use the subprocess module. Example:

import subprocess

# Open the subprocess
proc = subprocess.open('device_console', stdin=subprocess.PIPE, stdout.subprocess.PIPE)

# Write a command
proc.stdin.write('list\n')

# Read the results back -- this will block until a line of input is received
listing = proc.stdout.readline()

# When you're done, close the input stream so the subprocess knows to exit
proc.stdin.close()

# Wait for subprocess to exit (optional) and get its exit status
exit_status = proc.wait()

Python subprocess get child's output

2 Answers2