M-x term & less -c

M-x term & less -c

[Mark Plaksin]

term doesn't clear the screen at the right time when you run 'less -c'.
I've noticed this on and off when piping commands through less.  If the
command takes a few moments to run you can see the problem.  Here's a
simple way to reproduce it with Emacs CVS as of a March 3rd:

emacs -Q
M-x term RET RET

Inside the term, type 'sleep 5 | less -c'.  '-c' tells less to clear the
screen first thing.  The screen doesn't clear until the sleep exits.

Run 'sleep 5 | less -c' again in the same term--the bottom half of the
screen clears and the top half is filled with lines containing only "~".
After sleep exits you get what you expect--the entire screen is cleared
and less is waiting for you to quit.

term-start-output-log says that before the sleep exits, less sends one
^M for every line in my window and then sends ESC[HESC[JESC[H.  After
the sleep exits, there is one of these lines for each line on my window:
ESC[00;31m~ESC[0mESC

Well, on the last line it actually draws "(END)" but surely that's not
relevant :)

Re: M-x term & less -c

[Dan Nicolaescu]

Mark Plaksin <happy@mcplaksin.org> writes:

  > term doesn't clear the screen at the right time when you run 'less -c'.
  > I've noticed this on and off when piping commands through less.  If the
  > command takes a few moments to run you can see the problem.  Here's a
  > simple way to reproduce it with Emacs CVS as of a March 3rd:
  > 
  > emacs -Q
  > M-x term RET RET
  > 
  > Inside the term, type 'sleep 5 | less -c'.  '-c' tells less to clear the
  > screen first thing.  The screen doesn't clear until the sleep exits.

Hmm, I could reproduce this with -Q, but not without it.

It turns out that having:
(setq redisplay-dont-pause t)
in .emacs makes it work.

Not sure what would the right fix be...

Re: M-x term & less -c

[Mark Plaksin]

Dan Nicolaescu <dann@ics.uci.edu> writes:

> Mark Plaksin <happy@mcplaksin.org> writes:
>
>   > emacs -Q
>   > M-x term RET RET
>   > 
>   > Inside the term, type 'sleep 5 | less -c'.  '-c' tells less to clear the
>   > screen first thing.  The screen doesn't clear until the sleep exits.
>
> Hmm, I could reproduce this with -Q, but not without it.
>
> It turns out that having:
> (setq redisplay-dont-pause t)
> in .emacs makes it work.
>
> Not sure what would the right fix be...

Thanks!  That fixes it for me too.