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.