I HOPE I'm never close enough to a bear that I can stick him with a knife.
I suppose as that last great act of defiance, the knife would be something you could use in a last stand, but I think the bear has a longer "reach" than I do. By the time I'm close enough to stick him, he's already had more than ample opportunity to smack me silly.
Heck, even most handguns (even if they were legal to carry in the park) are not going to drop a bear in his tracks, especially any handgun you'd carry in a concealed carry mode and want to lug around fishing all day. 9MM, 45, 38, 357, etc. would probably kill a bear eventually, but unless one was quite lucky, I doubt if they would make the kind of impression on an angry bear that most would think.
The loud bang would probably scare it off better than a bullet impact.
I'm by no means a "bear expert" so my approach is to try to make noise on the trail and to do the best I can to avoid close encounters with them.
I think I would need some extra baby wipes if I was 50' from a bear that was growling at me.