Indeed. Back when 300 and 1200 bps connections were a thing, Ctrl-O (flush) was a vital special character. You can actually see "flush = ^O" if you run "stty -a

Indeed. Back when 300 and 1200 bps connections were a thing, Ctrl-O (flush) was a vital special character. You can actually see "flush = ^O" if you run "stty -a" on Linux. However it's not part of Posix, and AFAIK has never been implemented on Linux. This sucks if you've gone through the trouble of hooking up a fun retro terminal or teletype to your machine.