How can I know when my screen was locked last time?

Question

Exist a log where I can look for that information? I want to know last days when my PC automatically locked the screen because was idle.

Answer 1

You can find the unlock screen events using the following command:

grep screen /var/log/auth.log*

But there is not so simple to find the lock screen events because by default doesn't exist any log for these events (as far as I know).

Anyway, you can run the following command for logging the lock screen events:

dbus-monitor --session "type='signal',interface='org.gnome.ScreenSaver'" | ( while true; do read X; if echo "$X" | grep "boolean true" &> /dev/null; then  echo "Screen locked on $(date)" > $HOME/lock_screen.log; fi; done )

in ~/lock_screen.log file.

If you like the above command, then use it in a script and make the script to run automatically at startup.

References:

• Logging lock-screen events
• Run script on screen lock/unlock