Comments on: python subprocess over shell

By: Links for 2010-05-10

Links for 2010-05-10 — Mon, 10 May 2010 22:46:00 +0000

[...] 07:26: python subprocess instead of shell http://explanatorygap.net/2010/05/10/python-subprocess-over-shell/ [...]

By: nigel kersten

nigel kersten — Mon, 10 May 2010 18:22:53 +0000

Yep. A custom function I often use is one that returns a tuple of (stdout, stderr, returncode) so you can use it however you want.

I don’t use it often, mainly because I still do python 2.4 work, but the convenience function check_call that appeared in 2.5 is quite useful too:

http://docs.python.org/library/subprocess.html#convenience-functions

subprocess.check_call(*popenargs, **kwargs)
Run command with arguments. Wait for command to complete. If the exit code was zero then return, otherwise raise CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute.

The arguments are the same as for the Popen constructor. Example:

>>> subprocess.check_call(["ls", "-l"])
0
New in version 2.5.

By: Preston

Preston — Mon, 10 May 2010 18:16:35 +0000

for blind calls to commands (no communication needed), I actually have this snippet built into my TextMate boilerplate for Python sysadmin scripts:

from subprocess import Popen, call, STDOUT, PIPE

def sh(cmd):
return Popen(cmd,shell=True,stdout=PIPE,stderr=PIPE).communicate()[0]

so calling a shell command is as easy as:

printer_xml = sh(‘system_profiler -xml SPPrintersDataType’)