@OtherMichael, I understand:
@discbot roll d20 - roll a single 20 sided dice
@discbot roll 2d20 - roll two dice
@discbot roll 2d20+5 - roll two dice with a positive modifier
@discbot roll 2d20-5 - roll two dice with a negative modifier
@discbot hello - discbot will respond with a greeting
@discbot help - shows all discbot commands