Use Popen.wait: process = subprocess.Popen([“your_cmd”]…) process.wait() Or check_output, check_call which all wait for the return code depending on what you want to do and the version of python. If you are using python >= 2.7 and you don’t care about the output just use check_call. You can also use call but that will not raise … Read more
You can’t always log all the sub-processes as they are created, since they can in turn create new processes that you are not aware of. However, it’s pretty simple to use psutil to find them: import psutil current_process = psutil.Process() children = current_process.children(recursive=True) for child in children: print(‘Child pid is {}’.format(child.pid))
To open in a different console, do (tested on Win7 / Python 3): from subprocess import Popen, CREATE_NEW_CONSOLE Popen(‘cmd’, creationflags=CREATE_NEW_CONSOLE) input(‘Enter to exit from Python script…’) Related How can I spawn new shells to run python scripts from a base python script?
In Python < v3.5: A close read of the source code gives the answer. In particular, the documentation is misleading when it says: subprocess.STDOUT Special value that (…) indicates that standard error should go into the same handle as standard output. Since stdout is set to “default” (-1, technically) when stderr=subprocess.STDOUT is evaluated, stderr is … Read more
Avoid os.system() by all means, and use subprocess instead: with open(os.devnull, ‘wb’) as devnull: subprocess.check_call([‘/etc/init.d/apache2’, ‘restart’], stdout=devnull, stderr=subprocess.STDOUT) This is the subprocess equivalent of the /etc/init.d/apache2 restart &> /dev/null. There is subprocess.DEVNULL on Python 3.3+: #!/usr/bin/env python3 from subprocess import DEVNULL, STDOUT, check_call check_call([‘/etc/init.d/apache2’, ‘restart’], stdout=DEVNULL, stderr=STDOUT)
The important thing about the optimization suggestion is to make sure that my_function() is only invoked in a subprocess. The deepcopy and del are irrelevant — once you create five million distinct integers in a process, holding onto all of them at the same time, it’s game over. Even if you stop referring to those … Read more
In case your process produces significant amounts of output that you don’t want to buffer in memory, you should redirect the output to the electronic trash can: subprocess.run([“pdflatex”, filename], stdout=subprocess.DEVNULL) The special value DEVNULL indicates that the output is sent to the appropriate null device of your operating system (/dev/null on most OSes, nul on … Read more
Check out the subprocess manual. You have options with subprocess to be able to redirect the stdin, stdout, and stderr of the process you’re calling to your own. from subprocess import Popen, PIPE, STDOUT p = Popen([‘grep’, ‘f’], stdout=PIPE, stdin=PIPE, stderr=STDOUT) grep_stdout = p.communicate(input=”one\ntwo\nthree\nfour\nfive\nsix\n”)[0] print grep_stdout You can also interact with a process line by … Read more
You’re doing blocking reads to two files; the first needs to complete before the second starts. If the application writes a lot to stderr, and nothing to stdout, then your process will sit waiting for data on stdout that isn’t coming, while the program you’re running sits there waiting for the stuff it wrote to … Read more
The subprocess.run() function only exists in Python 3.5 and newer. It is easy enough to backport however: def run(*popenargs, **kwargs): input = kwargs.pop(“input”, None) check = kwargs.pop(“handle”, False) if input is not None: if ‘stdin’ in kwargs: raise ValueError(‘stdin and input arguments may not both be used.’) kwargs[‘stdin’] = subprocess.PIPE process = subprocess.Popen(*popenargs, **kwargs) try: … Read more