'Show all authentication methods available.'

def opt_help_auth(self):

    self.authOutput.write('Usage:    --auth    AuthType[:ArgString]\n')
    self.authOutput.write('For    detailed    help:    --help-auth-type    AuthType\n')
    self.authOutput.write('\n')
    firstLength = 0
    for factory in self._checkerFactoriesForOptHelpAuth():
        if (len(factory.authType) > firstLength):
            firstLength = len(factory.authType)
    formatString = ('        %%-%is DCTB %%s\n' % firstLength)
    self.authOutput.write((formatString % ('AuthType', 'ArgString    format')))
    self.authOutput.write((formatString % ('========', '================')))
    for factory in self._checkerFactoriesForOptHelpAuth():
        self.authOutput.write((formatString % (factory.authType, factory.argStringFormat)))
    self.authOutput.write('\n')
    raise SystemExit(0)
