###
6.20.2.7 Putting it all together

Here's what `optparse`-based scripts typically look like:

    from optparse import OptionParser
    [...]
    def main():
        usage = "usage: \%prog [-f] [-v] [-q] firstarg secondarg"
        parser = OptionParser(usage)
        parser.add_option("-f", "--file", type="string", dest="filename",
                          help="read data from FILENAME")
        parser.add_option("-v", "--verbose",
                          action="store_true", dest="verbose")
        parser.add_option("-q", "--quiet",
                          action="store_false", dest="verbose")

        (options, args) = parser.parse_args()
        if len(args) != 1:
            parser.error("incorrect number of arguments")

        if options.verbose:
            print "reading \%s..." \% options.filename
        [... go to work ...]

    if __name__ == "__main__":
        main()