Ubuntu – Unlock login screen using command line

command linegnomelock-screen

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.

Best Answer

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 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

Related Solutions

Ubuntu – Cannot login through the command line

Your fullname (or display name) may be in the form firstname-space-initial-period but your Unix username (as required at the commandline login prompt) will be a single word like john or smithj or janesmith99

If you can't remember what username you used when you set up the account (and you can't open an application such as the Nautilus file manager that would enable you to figure it out - by default, the username will be the same as the final component of the pathname of your home directory), then you can reboot into recovery mode and check for your username in the /etc/passwd file - either by using

less /etc/passwd

to display the whole file, or for example using a command like

awk -F: '/FirstName/ {print $1}' /etc/passwd

where FirstName is replaced by your actual first name (or any other distinguising part of your fullname that you are certain you used) to match and print the relevant entry.

You should then be able to reboot, select the CtrlAltF1 virtual terminal once more, and try again with the recovered username.

Ubuntu – Lock screen does not unlock with correct password Gnome and Ubuntu 14.04

Neither of the other two answers solved the problem for me, but some additional searching led to this bug report:

sudo chown root:shadow /sbin/unix_chkpwd
sudo chmod 2755 /sbin/unix_chkpwd

which solved the issue for me.

Best Answer

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Ubuntu – Cannot login through the command line

Ubuntu – Lock screen does not unlock with correct password Gnome and Ubuntu 14.04

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