gnu screen and resizing terminal window

[Tim Woodall]

I have to use PuTTY to connect to a debian server. For reasons that are
outwith my control the ssh session disconnects every 24 hrs.

Therefore I run screen so after reconnecting I can recover to whereever
I was at.

However, the PuTTY window does not resize to whatever it was previously.
I can find lots of questions asking how to turn this feature off but
nothing on why it doesn't work for me.

I'm not wedded to screen - about the only feature I'm using is the
scrollback buffer - so a change change to tmux is possible if that will
help but I'd really like the resizing to work. Does this work for
anyone?

(long term I'm hoping to get permission to install cygwin and then use a
X server and xterms and ssh from inside them or, even better, a debian
laptop, but for now I'm stuck with putty)

Tim.

[Andrei POPESCU]

On Mi, 26 ian 22, 18:45:41, Tim Woodall wrote:
> I have to use PuTTY to connect to a debian server. For reasons that are
> outwith my control the ssh session disconnects every 24 hrs.
>
> Therefore I run screen so after reconnecting I can recover to whereever
> I was at.
>
> However, the PuTTY window does not resize to whatever it was previously.
> I can find lots of questions asking how to turn this feature off but
> nothing on why it doesn't work for me.
>
> I'm not wedded to screen - about the only feature I'm using is the
> scrollback buffer - so a change change to tmux is possible if that will
> help but I'd really like the resizing to work. Does this work for
> anyone?

As far as I recall the screen window size is limited to the smallest
terminal that is connected to the particular session.

Maybe screen thinks there are other connections still present?

Kind regards,
Andrei
--
http://wiki.debian.org/FAQsFromDebianUser

[Bijan Soleymani]

On 2022-01-26 1:45 p.m., Tim Woodall wrote:
> I have to use PuTTY to connect to a debian server. For reasons that are
> outwith my control the ssh session disconnects every 24 hrs.
>
> Therefore I run screen so after reconnecting I can recover to whereever
> I was at.
>
> However, the PuTTY window does not resize to whatever it was previously.
> I can find lots of questions asking how to turn this feature off but
> nothing on why it doesn't work for me.

As far as I know this is not a screen feature. Putty controls the window
size, it is determined by the default or whatever is saved for that
session. You can change what happens when you resize the putty window on
the machine running putty. There is no way for you to change the putty
screen from the debian side.

Screen does provide commands to resize the virtual terminal, however
neither putty nor xterm seem to support the termcap commands (apparently
it is Z0 and Z1).

What happens when you try to resize the screen using screen's windowing
commands:

^a : width 50
^a : height 15

(control-a, then colon, then width 50, then enter)

In my case I get a message that
Your termcap does not specify how to change the terminal's width to 50
and
Your termcap does not specify how to change the terminal's height to 15

That is with TERM set to xterm.

Bijan

[Bijan Soleymani]

On 2022-01-26 5:42 p.m., Bijan Soleymani wrote:
> As far as I know this is not a screen feature. Putty controls the window
> size, it is determined by the default or whatever is saved for that
> session. You can change what happens when you resize the putty window on
> the machine running putty. There is no way for you to change the putty
> screen from the debian side.

Actually apparently putty does support remote resizing. It just seems
that our systems lack the right termcap entries.

Bijan

[Bijan Soleymani]

On 2022-01-26 5:55 p.m., Bijan Soleymani wrote:
> Actually apparently putty does support remote resizing. It just seems
> that our systems lack the right termcap entries.

I managed to resize the putty window by running the command:
resize -s height width

so:
resize -s 24 80

Also adding this:
termcapinfo xterm WS=\E[8;%d;%dt

to:
/etc/screenrc

Allows screen to resize the putty session (with the :width and :height
commands).

But when quitting/restarting screen it puts the putty and the screen
session back to the original size.

Bijan

[Tim Woodall]

Thanks, that seems to be it.

I also get: (from outside screen)

$ resize 80 50
resize: Can't set window size under VT100 emulation

which I'm sure I already tested and it worked but I must have been doing
something different!

[Tim Woodall]

On Wed, 26 Jan 2022, Bijan Soleymani wrote:

Thanks, that gives me something to investigate. At the moment, adding
that causes the screen to resize to 80x24 when I attach or detatch which
is not what I want but it gives me something to explore.

Tim.