How to send `screen -X` command to the right user in a multi-attached session

Question

Let's say I want to bind a key sequence in GNU screen to jump to a specific window. I might do so like this:

bind ^t exec screen -X select foo

(I've deliberately simplified this; the real-world application execs a command which dynamically figures out which window to switch to, then runs the screen -X command.)

Great; this works well. The problem comes when I've attached (via screen -x) to the same session from a different machine. On the new machine, ^a^t does as expected and switches to the window. But, if I return to the original machine, leaving the new machine attached, then ^a^t switches to the window on the new machine. If I detach the new machine, everything goes back to working as normal.

Note that this is one session, so -S is of no use. The session is not password-protected. It also doesn't seem to relate to the exec machinery: while manually running screen -X select foo inside screen on the original machine works properly, running it in a separate terminal on the original machine (i.e. outside screen) still switches the window on the other machine.

How can I force screen -X to affect only the attached user on the same machine it's being run from? (Affecting both users/machines would also be acceptable, if that's easier.)

Answer 1

I think the at command should be a solution to what you are seeing. In the description for the at command in screen's man it says:

at [identifier][#|*|%] command [args ... ].
...
In shared windows the command will be repeated for each attached display.
...

Which sounds like it should switch the window in both places.