Fighter Knife

How would a Karate fighter defend against a knife or a weapon like a bat?

I am not a Karate fighter, so I can not answer how a Karate fighter handle this. I will admit I am not familiar with Karate’s weapon disarming techniques. What I will say is this
An armed opponent is not the same as an unarmed one
Parrying a knife with your hand will get you cut or stabbed
Parrying a bat will get your arm broken
If you remove the weapon from your assailant why would you toss it
A situation like this should never be thought of as easy
Running is always a good choice if possible

Pathfinder DEF TAC Fighter Knife Unboxing