HEY, MAN!

"Hey, man!" "Say, man!" "Oh, man!" "Man, oh, man!"

I wondered where the term "man" originated when used in those ways.

When I wondered aloud to my fount-of-knowledge, he said, "Oh, it's from black jazz musicians who were tired of being referred to as boys!"

I screaked, "HOW would you know that?"

"I just know things, MAN!"

When I persisted, he challenged, "Just look it up, MAN!"

Oftentimes, I don't know whether he is putting me on, just being quick-witted, or a combination of both.  I have researched for an hour and have found nothing to substantiate his assertion. 

 When he reads this, he might--or might not--tell me HOW he knows!  Man, oh man!