echoctl: Control echoes give literal ^ + printable
-echoctl: Control echoes give raw control character

-echoe -echoprt: Backspace gives ^?
echoe -echoprt: Backspace gives character erase
(-)echoe echoprt: Backspace gives \ if last press wasn't Backspce, then erased characters, and / when non-backspace pressed or end of line erased


crtkill (-)echoe -echok: Kill gives ^U
crtkill -echoe echok: Kill gives ^U and newline (N_TTY comment says no newline, bug?)
crtkill echoe echok: Kill erases line with backspace

-crtkill -echok: Kill gives ^U
-crtkill echok: Kill gives ^U and newline