It's not what you do, but the way how you do it that makes the difference!  A bright flashlight  held in one hand and shined into someone's eyes can temporarily blind a person's vision that is armed with a knife, so that you can thrust a broom handle into the solar plexus area repeatedly using your other hand.  (A broom hurts worse than a kick and is smarter and safer).  You can then strike the temple area with the flashlight, and using follow through get his weapon holding arm in what is called an OVER-ARM LOCK or  Figure Four Double Wristlock that puts his hand in a HAMMERLOCK hold.  Stomping his thigh of the same side as his arm holding the weapon makes it easier to apply the Double Wrist Lock, and his free arm could easily prevent the move unless you do stomp.  His arm probably won't be strong enough to to prevent you getting the hold if you use the stomp. 

Be careful with using any technique that turns your back to an attacker, especially when weapons are used.

Dennis