In a recent post in Meta, the title:
Preguntad, preguntad, malditos
does not, as I had expected, carry exclamation marks. I have looked through similar questions on this site and at this section in the DPD but I could find nothing on this site about commands specifically and the DPD is more about the correct way to write them.
So my question is whether the rule is that commands should have them, as in ¡Cállate! or is it optional?