How to log out all inactive terminal sessions in GNU/Linux?

Question

Since I switched to Wayland on Debian11/KDE starting the computer from standby in around 90% of cases shows a black screen and one needs to use ctrl+alt+f{id} and run loginctl unlock-session {id2} to be able to switch back to the running session by pressing ctrl+alt+F1.

This is a security issue because one can resume the session without having to enter the password if it has been entered before and this still hasn't been fixed for Debian11/KDE.

The session is shown with the who command. I think configuring $TMOUT (which isn't set by default) as recommended elsewhere would also log out the current session, not just the inactive terminal session/s.

How can I log out (automatically or not) all inactive terminal sessions (exclusively) which I started to be able to resume from standby due to the Wayland-KDE/Debian11 bugs?

Answer 1

TMOUT causes idle interactive shells to exit, it doesn’t close desktop sessions.

If you don’t want to have to remember to log out from your “rescue” VTs, it seems like a good solution to me: your rescue VT will automatically log out after however many seconds you specify in TMOUT (e.g. 120 — note that this will affect terminal emulators too, so don’t choose too small a value).

You could also replace your rescue shell with loginctl:

exec loginctl ...

That way, once loginctl completes, you’ll be logged out of your rescue VT.