Okay so I suddenly have no idea how to say the imperative of saber.
This was my reasoning until arriving to a comical dead end:
Ir = Ve
Comer = Come
Ser = Sé
Saber = Se? Sabé? Sepe!?
Per answers the correct form is Sabe.
But sabe isn't used at all! People never use it! People rather say "Debes saber que..." or some other form. not like other verbs as ir "Ve ya." Why is that??