subprocess-zombie.py

import os
import subprocess
import time


## If the parent process is ignoring that output, 
## the Popen call cannot destroy the process as it has data sitting in a pipe and generates zombie processes.

#p = subprocess.Popen('ls -l /tmp', shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
#time.sleep(10)


## ---


## Right way how to use subprocess Popen without zombie processes after
with subprocess.Popen('ls -l /tmp', shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT) as p:
    try:
        std_out, std_err = p.communicate(timeout=5)
    except subprocess.TimeoutExpired:
        p.kill()
        std_out, std_err = p.communicate()
    except:
        p.kill()
        p.wait()
        raise
    time.sleep(10)
    return_code = p.poll()

    print(return_code)
    print(std_out.decode('ascii').strip())