Not exactly a programming question, but if you use Terminal you're likely a programmer, so I feel it's the best suited subforum: Have you noticed the Terminal window having some delay when refreshing stdout/stderr output from command line programs? I'm on 10.11.6 now, and I think it didn't happen in the first El Capitan versions, I believe this lagging came with some 10.11.x update. It's a several-seconds delay. I think you cancel the delay when moving the mouse pointer over the Terminal window, then it gets refreshed (or that's my impression). Do you experience it? Does it affect Sierra too? Did you fix it somehow?