Function _get_command_stdout

Lib/uuid.py:424–452

(command, *args)

def _get_command_stdout(command, *args):
    import io, os, shutil, subprocess

    try:
        path_dirs = os.environ.get('PATH', os.defpath).split(os.pathsep)
        path_dirs.extend(['/sbin', '/usr/sbin'])
        executable = shutil.which(command, path=os.pathsep.join(path_dirs))
        if executable is None:
            return None
        # LC_ALL=C to ensure English output, stderr=DEVNULL to prevent output
        # on stderr (Note: we don't have an example where the words we search
        # for are actually localized, but in theory some system could do so.)
        env = dict(os.environ)
        env['LC_ALL'] = 'C'
        # Empty strings will be quoted by popen so we should just omit it
        if args != ('',):
            command = (executable, *args)
        else:
            command = (executable,)
        proc = subprocess.Popen(command,
                                stdout=subprocess.PIPE,
                                stderr=subprocess.DEVNULL,
                                env=env)
        if not proc:
            return None
        stdout, stderr = proc.communicate()
        return io.BytesIO(stdout)
    except (OSError, subprocess.SubprocessError):
        return None


# For MAC (a.k.a. IEEE 802, or EUI-48) addresses, the second least significant