What is a knife designed to do? I can pick up any knife in my drawer at home and gravely injure someone with it, and it doesn't help me clean my driveway or change the channel on my tv.
Since you can't seem to understand that I was just throwing out random examples I guess I need to clarify that I wasn't implying a knife could do those things. Then again, you're the one who brought up a knife in the first place so there's a reason I didn't mention it.
As for what I can do with a knife, I can cut my food, cut wood, a tool for crafting, I can think of dozens of non-violent ways two use a knife.