__init__.py 文件源码

def parseopts(args):
    parser = create_main_parser()
    parser.main = True # so the help formatter knows

    # create command listing
    command_summaries = get_summaries()

    description = [''] + ['%-27s %s' % (i, j) for i, j in command_summaries]
    parser.description = '\n'.join(description)

    options, args = parser.parse_args(args)

    if options.version:
        sys.stdout.write(parser.version)
        sys.stdout.write(os.linesep)
        sys.exit()

    # pip || pip help || pip --help -> print_help()
    if not args or (args[0] == 'help' and len(args) == 1):
        parser.print_help()
        sys.exit()

    if not args:
        msg = ('You must give a command '
               '(use "pip --help" to see a list of commands)')
        raise CommandError(msg)

    command = args[0].lower()

    if command not in commands:
        guess = get_similar_commands(command)

        msg = ['unknown command "%s"' % command]
        if guess:
            msg.append('maybe you meant "%s"' % guess)

        raise CommandError(' - '.join(msg))

    return command, options, args, parser