Check a command's return code when subprocess raises a CalledProcessError exception

Question

I want to capture the stdout stream of a shell command in a python (3) script, and being able, at the same time, to check the return code of the shell command i

Answer 1

Most likely my answer is no longer relevant, but I think it may be solved with this code:

import subprocess
failing_command='ls non_existent_dir'

try:
    subprocess.check_output(failing_command, shell=True, stderr=subprocess.STDOUT)
except subprocess.CalledProcessError as e:
    ret =   e.returncode 
    if ret in (1, 2):
        print("the command failed")
    elif ret in (3, 4, 5):
        print("the command failed very much")

Answer 2

To get both the process output and the returned code:

from subprocess import Popen, PIPE

p = Popen(["ls", "non existent"], stdout=PIPE)
output = p.communicate()[0]
print(p.returncode)

subprocess.CalledProcessError is a class. To access returncode use the exception instance:

from subprocess import CalledProcessError, check_output

try:
    output = check_output(["ls", "non existent"])
    returncode = 0
except CalledProcessError as e:
    output = e.output
    returncode = e.returncode

print(returncode)