def command_start(args):
    procfile_path = _procfile_path(args.app_root, _choose_procfile(args))
    procfile = _procfile(procfile_path)

    concurrency = _parse_concurrency(args.concurrency)
    env = _read_env(args.app_root, args.env)
    quiet = _parse_quiet(args.quiet)
    port = _choose_port(args, env)

    if args.processes:
        processes = compat.OrderedDict()
        for name in args.processes:
            try:
                processes[name] = procfile.processes[name]
            except __HOLE__:
                raise CommandError("Process type '{0}' does not exist in Procfile".format(name))
    else:
        processes = procfile.processes

    manager = Manager()

    for p in environ.expand_processes(processes,
                                      concurrency=concurrency,
                                      env=env,
                                      quiet=quiet,
                                      port=port):
        e = os.environ.copy()
        e.update(p.env)
        manager.add_process(p.name, p.cmd, quiet=p.quiet, env=e)

    manager.loop()
    sys.exit(manager.returncode)
dataset/ETHPy150Open nickstenning/honcho/honcho/command.py/command_start