Just modified the UNIX V4 kernel and utilities so it supports backspace for deleting characters. Pressing backspace instead of # was the top mistake made by LRC attendees, so this would make it easier to use for modern users.

The erase (delete last character) and kill (clear current line) characters were fixed to # and @, inherited from Multics, and not made configurable until a few months later around November 1974. Perhaps this change reflects the first time a video terminal was used for UNIX.

I made it send BS SP BS when backspace is pressed to visually clear the character, but this unfortunately makes it clear commands' output too. For example, this lets you visually clear the shell prompt. I could fix this by implementing something like curses, but that would move the logic to user space and incur overhead for swapping the process for a context switch on every character press. This was a complaint of early vi. Maybe I could track the column of the last printed text and not let you visually backspace before that?

#unix #retrocomputing