Wondering

Long time Unix geek here. Solving the puzzle I was like, “oh, the rest of the world knows that ! Is bang too? How am I just now learning this? “ Sounds like from this column that’s not necessarily the case, though. Drat (bang)

Fun puzzle! I figured out the trick in a reasonable amount of time, but somehow took me a while to figure out what the wordplay behind it was supposed to be, even after reading this column and the comments. Finally, went back into the puzzle, stared at it some more, and "Ooooohhhhhh!" Good one! 13-down threw me for a loop though; I briefly feared I'd been stealing from trade shows for decades. Had no idea that word had so many alternate definitions!