Given the command-line arguments, this creates a parser appropriate
        to that command, and runs it.

def execute(self):
        """
        Given the command-line arguments, this creates a parser appropriate
        to that command, and runs it.
        """

        # retrieve default language from system environment
        default_locale = os.environ.get('LANG', 'en_US').split('.')[0]
        if default_locale not in AVAILABLE_LOCALES:
            default_locale = DEFAULT_LOCALE

        epilog = """supported locales:

  {0}

  Faker can take a locale as an optional argument, to return localized data. If
  no locale argument is specified, the factory falls back to the user's OS
  locale as long as it is supported by at least one of the providers.
     - for this user, the default locale is {1}.

  If the optional argument locale and/or user's default locale is not available
  for the specified provider, the factory falls back to faker's default locale,
  which is {2}.

examples:

  $ faker address
  968 Bahringer Garden Apt. 722
  Kristinaland, NJ 09890

  $ faker -l de_DE address
  Samira-Niemeier-Allee 56
  94812 Biedenkopf

  $ faker profile ssn,birthdate
  {{'ssn': u'628-10-1085', 'birthdate': '2008-03-29'}}

  $ faker -r=3 -s=";" name
  Willam Kertzmann;
  Josiah Maggio;
  Gayla Schmitt;

""".format(', '.join(sorted(AVAILABLE_LOCALES)),
           default_locale,
           DEFAULT_LOCALE)

        formatter_class = argparse.RawDescriptionHelpFormatter
        parser = argparse.ArgumentParser(
            prog=self.prog_name,
            description='{0} version {1}'.format(self.prog_name, VERSION),
            epilog=epilog,
            formatter_class=formatter_class)

        parser.add_argument("--version", action="version",
                            version="%(prog)s {0}".format(VERSION))

        parser.add_argument('-v',
                            '--verbose',
                            action='store_true',
                            help="show INFO logging events instead "
                            "of CRITICAL, which is the default. These logging "
                            "events provide insight into localization of "
                            "specific providers.")

        parser.add_argument('-o', metavar="output",
                            type=argparse.FileType('w'),
                            default=sys.stdout,
                            help="redirect output to a file")

        parser.add_argument('-l', '--lang',
                            choices=AVAILABLE_LOCALES,
                            default=default_locale,
                            metavar='LOCALE',
                            help="specify the language for a localized "
                            "provider (e.g. de_DE)")
        parser.add_argument('-r', '--repeat',
                            default=1,
                            type=int,
                            help="generate the specified number of outputs")
        parser.add_argument('-s', '--sep',
                            default='\n',
                            help="use the specified separator after each "
                            "output")

        parser.add_argument('--seed', metavar='SEED',
                            type=int,
                            help="specify a seed for the random generator so "
                            "that results are repeatable. Also compatible "
                            "with 'repeat' option")

        parser.add_argument('-i',
                            '--include',
                            default=META_PROVIDERS_MODULES,
                            nargs='*',
                            help="list of additional custom providers to "
                            "user, given as the import path of the module "
                            "containing your Provider class (not the provider "
                            "class itself)")

        parser.add_argument('fake',
                            action='store',
                            nargs='?',
                            help="name of the fake to generate output for "
                                 "(e.g. profile)")

        parser.add_argument('fake_args',
                            metavar="fake argument",
                            action='store',
                            nargs='*',
                            help="optional arguments to pass to the fake "
                                 "(e.g. the profile fake takes an optional "
                                 "list of comma separated field names as the "
                                 "first argument)")

        arguments = parser.parse_args(self.argv[1:])

        if arguments.verbose:
            logging.basicConfig(level=logging.DEBUG)
        else:
            logging.basicConfig(level=logging.CRITICAL)

        random.seed(arguments.seed)
        seeds = random.sample(range(arguments.repeat*10), arguments.repeat)

        for i in range(arguments.repeat):

            print_doc(arguments.fake,
                      arguments.fake_args,
                      lang=arguments.lang,
                      output=arguments.o,
                      seed=seeds[i],
                      includes=arguments.include,
                      )
            print(arguments.sep, file=arguments.o)

            if not arguments.fake:
                # repeat not supported for all docs
                break