> Try the xev program. It will show X events and may reveal the keypresses > you're interested in.
Thanks. The mystery here is on the other side - things received by the terminal, not keys pressed. But I thought of 'strace'. I attached that to the Bash process and clearly saw it sending only space characters, no backspaces: pselect6(1, [0], NULL, NULL, NULL, {[], 8}) = 1 (in [0]) read(0, "q", 1) = 1 write(2, " ", 1) = 1 pselect6(1, [0], NULL, NULL, NULL, {[], 8}) = 1 (in [0]) read(0, "q", 1) = 1 write(2, " ", 1) = 1 Compared to the better Bash 4 behavior: read(0, "q", 1) = 1 write(2, "\10 \10", 3) = 3 read(0, "q", 1) = 1 write(2, "\10 \10", 3) = 3 (N.B. "q" is the "erase" character for this experiment). (N.B. "\10" is ASCII backspace (ctl-H) in octal) I see what is probably the crucial difference between my working Bash 4 and my nonworking Bash 5: Different Ncurses shared libraries. The former uses libncurses.so.5 _and_ libtinfo.so.5, while the latter uses only libtinfo.so.6. Still doesn't explain why this is a problem only for me, though. -- Bryan Henderson San Jose, California