In that sense, all subprocesses are background processes. wait() method explicitly if you want to wait for the child process. Popen() starts a child process-it does not wait for it to exit. How to verify that via another terminal window: $ ps aux | grep python > p = subprocess.Popen(, stdout=subprocess.PIPE, stderr=subprocess.STDOUT) print('finished') Myperl.Here is verified example for Python REPL: > import subprocess Subprocess.check_call(shlex.split('perl ')) cmd = 'echo whoop' # or cmd = 'ls 'does not exist'' The output of the process is directly written to the controlling terminal - no need to redirect the output.įinally, if cmd is a compound of a path to an executable and its arguments then use shlex.split.Įg. No need to check the return value as check_call throws an exception (which contains the exit code) if the process returns with a non-zero exit code. Try using subprocess.call or even subprocess.check_call. And it doesn't look like you need a shell at all. That is, you create pipes, and then just reprint to stdout with your own message. You also don't really need to use Popen as you're not really using its features. Presumably perl is not closing stdout as it's leaving it open for it's own subprocess to write to. Communicate is explicitly designed to wait until the stdout of the process has closed. Print 'This line is printed only when the GUI process is terminated.'ĭon't use communicate. My 'General Tool' last Main lines (Written in Perl): if ($args->'.format(exit_code, stdout) I need municate() to return once the main process is terminated, and not to wait for the subprocesses that run on the background. I have to manually close the GUI (which is a subprocess that runs on the BG), so municate() returns. The problem is that municate() continues waiting to the process, although it's already terminated.

My 'general tool' runs for ~1 second, loads the GUI process on the background and exits immediately.

I call my 'general tool' from a Python script, using Popen and municate() method. I work in Unix, and I have a 'general tool' that loads another process (GUI utility) on the background, and exits.

Python subprocess call background