Generates formatted help output.

        Returns the help string.

def help(self):
        '''
        Generates formatted help output.

        Returns the help string.
        '''
        modules = {}
        help_string = "\n"
        help_string += "Binwalk v%s\n" % binwalk.__version__
        help_string += "Craig Heffner, ReFirmLabs\n"
        help_string += "https://github.com/ReFirmLabs/binwalk\n"
        help_string += "\n"
        help_string += "Usage: binwalk [OPTIONS] [FILE1] [FILE2] [FILE3] ...\n"

        # Build a dictionary of modules and their ORDER attributes.
        # This makes it easy to sort modules by their ORDER attribute for
        # display.
        for module in self.list(attribute="CLI"):
            if module.CLI:
                modules[module] = module.ORDER

        for module in sorted(modules, key=modules.get, reverse=True):
            help_string += "\n%s Options:\n" % module.TITLE

            for module_option in module.CLI:
                if module_option.long and not module_option.hidden:
                    long_opt = '--' + module_option.long

                    if module_option.dtype:
                        optargs = "=<%s>" % module_option.dtype
                    else:
                        optargs = ""

                    if module_option.short:
                        short_opt = "-" + module_option.short + ","
                    else:
                        short_opt = "   "

                    fmt = "    %%s %%s%%-%ds%%s\n" % (25 - len(long_opt))
                    help_string += fmt % (short_opt, long_opt, optargs, module_option.description)

        return help_string + "\n"