The right module to use is subprocess. Older modules and functions that should be avoided are:

• os.system
• os.spawn*
• os.popen*
• popen2.*
• commands.*

Run command with arguments. Wait for command to complete, then return the returncode attribute.

retcode = subprocess.call(["ls", "-l"])

subproc = subprocess.Popen(cmd, stdin=None, stdout=subprocess.PIPE)
output  = subproc.communicate()[0]
retcode = subproc.returncode
for line in output.splitlines():
    print line