Answers for "start a subprocess python"

python subprocess with environment variables

import subprocess, os
my_env = os.environ.copy()
my_env["PATH"] = "/usr/sbin:/sbin:" + my_env["PATH"]
subprocess.Popen(my_command, env=my_env)

python subprocess exception handling

try:
    subprocess.check_output(...)
except subprocess.CalledProcessError as e:
    print(e.output)

python run function in subprocess

# no, we can't use subprocess module for that
import multiprocessing
import time


def task(*args):
    print("wait")
    time.sleep(2)
    print(*args)
    print("finished")


if __name__ == "__main__":
    # child process has different __name__
    process = multiprocessing.Process(target=task, args=(69, 66))
    # args must be pickable
    # Pickable objects https://docs.python.org/3/library/pickle.html#what-can-be-pickled-and-unpickled
    process.start()
    process.join()  # make sure this gets executed only after process starts