Three different ways to run bash commands.

bash.py

import subprocess

#! /usr/bin/env python
import subprocess
# Use a sequence of args
return_code = subprocess.call(["echo", "hello sequence"])
 
# Set shell=true so we can use a simple string for the command
return_code = subprocess.call("echo hello string", shell=True)
 
# subprocess.call() is equivalent to using subprocess.Popen() and wait()
proc = subprocess.Popen("echo hello popen", shell=True)
return_code = proc.wait() # wait for process to finish so we can get the return code

#! /usr/bin/env python
import subprocess
# Put stderr and stdout into pipes
proc = subprocess.Popen("echo hello stdout; echo hello stderr >&2", \
        shell=True, stderr=subprocess.PIPE, stdout=subprocess.PIPE)
return_code = proc.wait()
# Read from pipes
for line in proc.stdout:
    print("stdout: " + line.rstrip())
for line in proc.stderr:
    print("stderr: " + line.rstrip())