How to get data from command line from within a Python program?

Question

I want to run a command line program from within a python script and get the output.

How do I get the information that is displayed by foo so that I can use it in my script?

For example, I call foo file1 from the command line and it prints out

Size: 3KB Name: file1.txt Other stuff: blah 

How can I get the file name doing something like filename = os.system('foo file1')?

Answer 1

Use the subprocess module:

import subprocess  command = ['ls', '-l'] p = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.IGNORE) text = p.stdout.read() retcode = p.wait() 

Then you can do whatever you want with variable text: regular expression, splitting, etc.

The 2nd and 3rd parameters of subprocess.Popen are optional and can be removed.