Help with screen comand

[stan]

On Thu, Dec 05, 2019 at 09:45:07AM -0500, stan wrote:
> I have used the screen command in the past, but it has been quite a while.
> I am trying to set it up on an Ubuntu machine to allow other users to
> "shadow" my session as a teaching tool. I found this link:
> 
> https://unix.stackexchange.com/questions/163872/sharing-a-terminal-with-multiple-users-with-screen-or-otherwise
> 
> But I am having issues making it work I have run
> 
> screen -d -m -S multisession
> 
> followed by
> 
> screen -r multisession
> 
> And, indeed this does put me in a session, but I get no response to the
> CTRL A keystroke. Should this not put me in the command prompt (: at the
> bottom of the screen?

OK, so I got that part working, not certain what I was doing wrong. Perhaps
I had to type the : 

In any case, I know have a session sunning, and I (as my user) am attached
to it:

stan at ica-db:~$ screen -list
There are screens on:
22859.test      (12/05/19 14:58:19)     (Multi, attached)
22669.multisession      (12/05/19 14:51:08)     (Detached)
22658.multisession      (12/05/19 14:51:04) (Detached)
3 Sockets in /run/screen/S-stan.

The 2  sessions name multisession are leftovers and I need to figure out
how to kill the, So  I add user doc to the acl list, but logged in as that
user here is what happens when I try to attach:

doc at ica-db:~$ screen -x stan/test
chmod /dev/pts/5: Operation not permitted
doc at ica-db:~$ 

What am I doing wrong?

-- 
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
						-- Benjamin Franklin