Python subprocess get children's output to file and terminal?

The call() function is just Popen(*args, **kwargs).wait(). You could call Popen directly and use stdout=PIPE argument to read from p.stdout:

#!/usr/bin/env pythonimport sysfrom subprocess import Popen, PIPEfrom threading import Threaddef tee(infile, *files):    """Print `infile` to `files` in a separate thread."""    def fanout(infile, *files):        with infile:            for line in iter(infile.readline, b""):                for f in files:                    f.write(line)    t = Thread(target=fanout, args=(infile,) + files)    t.daemon = True    t.start()    return tdef teed_call(cmd_args, **kwargs):    stdout, stderr = [kwargs.pop(s, None) for s in ["stdout", "stderr"]]    p = Popen(        cmd_args,        stdout=PIPE if stdout is not None else None,        stderr=PIPE if stderr is not None else None,        **kwargs    )    threads = []    if stdout is not None:        threads.append(            tee(p.stdout, stdout, getattr(sys.stdout, "buffer", sys.stdout))        )    if stderr is not None:        threads.append(            tee(p.stderr, stderr, getattr(sys.stderr, "buffer", sys.stderr))        )    for t in threads:        t.join()  # wait for IO completion    return p.wait()outf, errf = open("out.txt", "wb"), open("err.txt", "wb")assert not teed_call(["cat", __file__], stdout=None, stderr=errf)assert not teed_call(["echo", "abc"], stdout=outf, stderr=errf, bufsize=0)assert teed_call(["gcc", "a b"], close_fds=True, stdout=outf, stderr=errf)

You could use something like this:https://github.com/waszil/subpiper

In your callbacks you can do whatever you like, log, write to file, print, etc. It also supports non-blocking mode.

from subpiper import subpiperdef my_stdout_callback(line: str):    print(f'STDOUT: {line}')def my_stderr_callback(line: str):    print(f'STDERR: {line}')my_additional_path_list = [r'c:\important_location']retcode = subpiper(cmd='echo magic',                   stdout_callback=my_stdout_callback,                   stderr_callback=my_stderr_callback,                   add_path_list=my_additional_path_list)