[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Backspace echoed incorrectly with TERM=garbage

From: Bryan Henderson
Subject: Re: Backspace echoed incorrectly with TERM=garbage
Date: 18 Jun 2020 22:35:28 +0000

> When you press Backspace to erase a character, what normally happens is that
> three characters are sent to the terminal: backspace, space, and backspace.
> ...
> Is it possible that your terminal is receiving BS-space-BS and for whatever
> reason, is ignoring/discarding the two BS characters, and therefore not
> moving the cursor where it's supposed to be?  That's the best guess I
> have at the moment.

Thanks for that explanation.  This seems really likely, as it explains the
treatment of the other line editing commands.  Ctl-a results in no cursor
motion at all, while Ctl-u results in a number of spaces equal to the cursor
position being printed.  But both edit the line correctly.

I assumed from the beginning that the problem was somewhere in the pipeline
other than inside Bash, but I can't get around the fact that the problem
consistently occurs with Bash 5 and not Bash 4. The Bash 5 is both the one
that comes with Debian 10 and the alpha version I compiled myself yesterday.
The Bash 4 is what came with Debian 9 - I run it side by side on the Debian 10
system with the Debian 10 Bash and one exhibits the problem and the other does

Well, it turns out the 'script' program is not a reliable way to see what is
being sent to the terminal.  It does not report any control characters
received even when the cursor moves correctly.  Any ideas on how I could see
the raw character stream sent to a terminal?

Say, I wonder what intelligence Bash uses to decide how to move the cursor
to the left in the absence of terminfo.

Bryan Henderson                                   San Jose, California

reply via email to

[Prev in Thread] Current Thread [Next in Thread]