How to remotely detach a screen from another terminal

Question

So I have 2 terminals open in front of me;

1. /dev/pts/1 - 'the controller'
2. /dev/pts/2 - 'the receiver'

I am currently using ttyecho to execute commands in /pts2 from /pts1.
I can list the screens - ttyecho -n /dev/pts/2 screen -ls fine from /pts1 and see the results in /pts2.
I can attach to a screen ttyecho -n /dev/pts/2 screen -x [blah] from /pts1 on /pts2 fine.. But what I can't do, is when attached to a screen then detach from it.

So if /dev/pts/2 is then inside a screen, I am trying to detach from it by executing a command using ttyecho from /dev/pts1

I've tried sending...

ttyecho -n /dev/pts/2 ^a+d  
ttyecho -n /dev/pts/2 screen -d -r 
ttyecho -n /dev/pts/2 screen -D -RR
ttyecho -n /dev/pts/2 screen -d -r
ttyecho -n /dev/pts/2 screen -DRi
ttyecho -n /dev/pts/2 Ctrl+a+d
ttyecho -n /dev/pts/2 Ctrl+a d
ttyecho -n /dev/pts/2 CTRL + A
ttyecho -n /dev/pts/2 control+a

So I guess what I need is either:

• A command I can send that will detach the screen OR
• Someway to send some kind of pseudo keyboard commands via ttyecho to that other screen to detach it.

Any help most appreciated.

Answer 1

You can do

$ screen -ls

This will list all the screen sessions like this.

There are screens on:
        8365.pts-6.vm2    (Attached)
        7317.pts-1.vm2    (Attached)
2 Sockets in /var/run/screen/S-root.

Then you can detach any screen session with the help of screen id.

For eg:

$ screen -d 8365
[8365.pts-6.vm2 detached.]

Answer 2

There’s no need to use ttyecho to detach the screen session, you can ask screen to do it for you:

screen -d pts-2

This will detach the session matching the name “pts-2”, which by default would match a screen session started on pts/2.