1

Has anyone been able to use crontab to lock their screen automatically? I have tried all the suggested methods here but none seems to work. I have an Ubuntu 20.04 gnome desktop and even the Screen Lock in the settings does not work. Only the following command works via the terminal:

gnome-screensaver-command -l

Here is the current code block accessed by sudo crontab -e:

SHELL=/bin/bash

0 /1  * * systemctl restart network-manager


0 /1  * * systemctl restart teamviewerd


/2  * * * gnome-screensaver-command -l

1 Answers1

1

A more universal way of locking the screen is using:

loginctl lock-session

Cron doesn't know the Session ID for loginctl

When you use loginctl lock-session from the command line, your session ID is already known. For example:

$ echo $XDG_SESSION_ID

c2


$ loginctl list-sessions


SESSION        UID USER             SEAT

        c2       1000 rick             seat0


1 sessions listed.

The above shows two ways you can get your Session ID from the command line.

This GitHub issue for loginctl explains why the variable XDG_SESSION_ID is unknown to systemd. The same case would apply to cron:

So from cron you could use loginctl lock-session c2 if you knew your session ID would always be c2. An easier way is to use lock-sessions.

I tried this on my system and it works. Try using this on your crontab -e:

*/5  *   *  *   *     loginctl lock-sessions

Now, every five minutes your screen will lock.

WinEunuuchs2Unix
  • 102,282
  • Hey, thanks for the quick reply. This command also works from the terminal but not with crontab. –  Feb 18 '22 at 20:52
  • @simguy I've revised the answer. – WinEunuuchs2Unix Feb 18 '22 at 23:44
  • Thanks, but this also has the same issue. I have also added some more details to my question.

    Here is how I implemented it for testing: "/2 * * * export DISPLAY=:0 && /bin/loginctl lock-session"

     –  Feb 19 '22 at 21:58
  • @simguy Check for errors using journalctl -xe. One could show up every two minutes. – WinEunuuchs2Unix Feb 20 '22 at 18:26
  • @simguy I've revised the answer after checking error messages and researching. If it works for you, remember to check the grey check mark next to the answer to show it solves the problem. – WinEunuuchs2Unix Feb 21 '22 at 14:37
  • yes, it does! Thank you very much; I will mark it as the solution. –  Feb 21 '22 at 22:10