How to get both return code and output from subprocess in Python? [duplicate]

Question

While developing python wrapper library for Android Debug Bridge (ADB), I'm using subprocess to execute adb commands in shell. Here is the simplified example:

import subprocess

...

def exec_adb_command(adb_command):
    return = subprocess.call(adb_command)

If command executed propery exec_adb_command returns 0 which is OK.

But some adb commands return not only "0" or "1" but also generate some output which I want to catch also. adb devices for example:

D:\git\adb-lib\test>adb devices
List of devices attached
07eeb4bb        device

I've already tried subprocess.check_output() for that purpose, and it does return output but not the return code ("0" or "1").

Ideally I would want to get a tuple where t[0] is return code and t[1] is actual output.

Am I missing something in subprocess module which already allows to get such kind of results?

Thanks!

Answer 1

Popen and communicate will allow you to get the output and the return code.

from subprocess import Popen,PIPE,STDOUT  out = Popen(["adb", "devices"],stderr=STDOUT,stdout=PIPE)  t = out.communicate()[0],out.returncode print(t) ('List of devices attached \n\n', 0) 

check_output may also be suitable, a non-zero exit status will raise a CalledProcessError:

from subprocess import check_output, CalledProcessError  try:     out = check_output(["adb", "devices"])     t = 0, out except CalledProcessError as e:     t = e.returncode, e.message 

You also need to redirect stderr to store the error output:

from subprocess import check_output, CalledProcessError  from tempfile import TemporaryFile  def get_out(*args):     with TemporaryFile() as t:         try:             out = check_output(args, stderr=t)             return  0, out         except CalledProcessError as e:             t.seek(0)             return e.returncode, t.read() 

Just pass your commands:

In [5]: get_out("adb","devices") Out[5]: (0, 'List of devices attached \n\n')  In [6]: get_out("adb","devices","foo") Out[6]: (1, 'Usage: adb devices [-l]\n')