Unlock login screen using command line

Question

Is it possible to unlock the 13.04 Gnome shell login screen from a command line? A user is logged in to Gnome shell, I can log in to a console as this user. I also have root access.

This is for accessing an active X11 display through VNC, without having to enter the password.

Executing

gnome-screensaver-command -d

as suggested in a blog post didn't help.

login screen

@Braiam: I can ssh in, that's not the problem. It's for accessing an active X11 display through VNC, but without having to enter the password. — krlmlr, Sep 03 '13 at 22:37

Mikko Rantalainen · Answer 1 · 2023-05-02T11:20:58.277

72

I'm assuming you have a recent linux system with systemd (e.g. Ubuntu 16.04 or newer).

If you need to unlock your own session, just run loginctl unlock-session (no root required because it's your own session). If you have multiple sessions and want to select just one, run loginctl list-sessions to identify session and then run e.g. loginctl unlock-session c187.

If you need to unlock all sessions, just run sudo loginctl unlock-sessions (note plural form). Note that this will immediately unlock ALL sessions no matter which user is running the screen saver.

If you need more information to identify the correct session, you can try something like this:

loginctl list-sessions --no-legend | while read id rest; do echo; loginctl show-session $id; done

edited May 02 '23 at 11:20

answered Jun 03 '17 at 08:59

Mikko Rantalainen

3,360

3

This is the only answer that works on 16.04 – lemonsqueeze Jun 15 '17 at 12:20
No need for sudo apparently – lemonsqueeze Jun 15 '17 at 13:29
1

You need sudo if you want to unlock screen savers of ALL sessions (including sessions not running with your user id). – Mikko Rantalainen Jun 20 '17 at 15:57
2

Also note the last s in unlock-sessions. If you want to unlock only your own session, just do loginctl unlock-session. – Mikko Rantalainen Jun 20 '17 at 16:04
Try hitting Tab after unlock-sessions and type anything listed from it if loginctl unlock-sessions doesn't work for any reasons. – Aryo Adhi May 10 '18 at 20:25
2

It should be the accepted answer! – bric3 Jul 21 '18 at 13:19
1

It still works on 22.04 – Oliver R. Aug 18 '22 at 06:40
1

Yes, 22.04 is newer release than 16.04. This answer uses official systemd features so it should be okay until systemd is replaced with something else. I'm not aware of any project to do that so I'd expect this answer to be valid around year 2030, too. – Mikko Rantalainen Aug 18 '22 at 13:48

steeldriver · Answer 2 · 2013-09-04T17:53:09.473

23

The problem with executing commands like gnome-screensaver-command from an SSH session is usually that they don't automatically connect to the appropriate session bus for the active desktop session - usually, setting the DISPLAY variable will fix that, for example these work for me (logged in via SSH as the same user who owns the locked X session, which is on DISPLAY :0):

$ DISPLAY=:0 gnome-screensaver-command -d

to unlock, and

$ DISPLAY=:0 gnome-screensaver-command -l

to lock.

Alternatively, you can toggle the active state using dbus-send - for example

$ export DISPLAY=:0
$ dbus-send --session \
          --dest=org.gnome.ScreenSaver \
          --type=method_call \
          --print-reply \
          --reply-timeout=20000 \
          /org/gnome/ScreenSaver \
          org.gnome.ScreenSaver.SetActive \
          boolean:false

Source: https://people.gnome.org/~mccann/gnome-screensaver/docs/gnome-screensaver.html#gs-examples

edited Sep 04 '13 at 17:53

answered Sep 04 '13 at 00:18

steeldriver

136,215
21
243
336

1

Unfortunately, neither of these methods unlocked the particular screen lock installed on my system (see screenshot). How can I find which process is responsible for locking the screen anyway? – krlmlr Sep 05 '13 at 19:22
1

Do the commands return an error? If so please post it. To see if a different screensaver is running you could try ps -fu <username> | grep saver - it is possible that xscreensaver is being used instead of gnome-screensaver, in which case you could try DISPLAY=:0 xscreensaver-command -deactivate. – steeldriver Sep 05 '13 at 20:31
1

I tested this answer on Ubuntu 14.04. It doesn't work. It unblanks the screen, but the screen remains locked. – kasperd Jun 10 '15 at 21:23
gnome-screensaver is not present on Ubuntu 22.04 it seems. gsd-screensaver might be the replacement. – Sridhar Sarnobat Jan 13 '23 at 18:39

score 7 · Answer 3 · answered Mar 08 '17 at 23:46

7

The following worked for me:

sudo killall gnome-screensaver

Especially helpful when you're logged in via SSH with another user.

answered Mar 08 '17 at 23:46

rosch

7,828

Confirmed, I had this problem when keyboard wasn't typing on the unlock screen, but was able to switch to terminal using CTRL+ALT+F3 and this screensaver killer helped. Then I just went CTRL+ALT+F2 back to the session that was locked :) – jave.web Oct 03 '18 at 05:53
This works when X2Go is showing the lock screen and not responding :) – endolith Feb 20 '19 at 06:57

score 3 · Answer 4 · answered Jan 23 '14 at 17:01

3

I had a problem with gnome 3's screen lock (screensaver) being stuck at a blank screen. I managed to work around it by replacing the gnome-shell window manager.

Ctrl+Alt+F1 and log in on a virtual console, then:

pkill -QUIT gnome-shell
DISPLAY=:0.0 gnome-shell -r &

(& Backgrounds the new gnome-shell so you can log out of the virtual console and keep it running. Alternatively use Ctrl+Z to suspend the gnome-shell process, and bg to background it.)

It might not be elegant, but it finally allowed me to get back to my desktop apps without having gnome force me to logout.

answered Jan 23 '14 at 17:01

T Percival

188

Thanks, I'll try and see if restarting gnome-shell works for me. – krlmlr Jan 23 '14 at 20:49
sending HUP instead of QUIT makes the second command unnecessary. – Rich Apr 21 '21 at 23:19

score 1 · Answer 5 · answered Feb 04 '17 at 22:01

I had a similar problem where the unlock screen wouldn't accept keyboard input sometimes. The way I finally solved it was to kill the several gnome-screensaver processes that were running, as well as one gnome-screensaver-dialog process. I'm guessing that whatever process was spawning 2 gnome-screensaver sessions was messing up my unlock screen. I'm actually supposed to be using xscreensaver instead, so maybe that messed with it.

Anyways, Ctrl+Alt+F1, look for screensaver processes running ps -aux | grep screen and kill them all. The gnome and xscreensaver commands listed in the other answers didn't work for me.

Unlock login screen using command line

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