remotely log out of (graphical) gnome session

Question

I have a (graphical) login session running on an office computer, and I'd like to log it out to save on a few computer resources.

I can ssh to the office box, but when I try gnome-session-quit I get this:

$ gnome-session-quit --logout --no-prompt

** (gnome-session-quit:18500): WARNING **: Command line `dbus-launch --autolaunch=fca99a51622d1930b068883b00000005 --binary-syntax --close-stderr' exited with non-zero exit status 1: Autolaunch error: X11 initialization failed.\n

** (gnome-session-quit:18500): WARNING **: Unable to start: Cannot open display: 

Makes sense as my $DISPLAY is empty (as it's a headless ssh session). When I run w, I see that the gnome-session is running on tty7. Is there a way I can pretend to be tty7 and initiate a logout? Is there a better way to do this?

Solution

After logging in with ssh, run:

env DISPLAY=:0.0 gnome-session-quit --logout

This will force a logout on the remote machine just as if you had logged out from the menu (but without prompting). You may need to run gnome-session-quit with --force-logout if there's an application with, for example, unsaved work, that would otherwise prevent a clean logout.

If you use a very old version (<2011) of GNOME, then you need to

env DISPLAY=:0.0 gnome-session-save --logout

... because gnome-session-save was renamed to gnome-session-quit in 2011.

Source

Comments

[Admin]

Usually with w, I see some line to this effect: muru :0 Wed20 ?xdm? 11:15m 1.10s gdm-session-worker [pam/gdm-password], the :0 being my relevant $DISPLAY. Don't you? You can also try pgrep -fa X and see what X is running with.

[Admin]

the entry from w with gnome-session had tty7 as the display, but the session had several other entries with :0 (terminals open I guess?). Checking the time column from w I realised :0 was the graphical session for sure (:

[drevicko]

On the office box, there is no gnome-session-save, but there is a gnome-session-quit which (with the rest of your answer) did the trick. I forgot to mention it's running Ubuntu 12.04 - perhaps that's why?

[muru]

@drevicko probably a typo. It's still -quit on a 12.04 box I have.

[Jetson Earth]

gnome-session-save was renamed to gnome-session-quit in 2011: mail.gnome.org/archives/desktop-devel-list/2011-February/…

[Jetson Earth]

@muru: updated answer accordingly

[Bloodgain]

Note that if the session is run under a session manager like Xvnc, it may not be on display 0.0. You can often find the display by doing a ps ux listing to find the process and see which display number is listed with the process. For example, my Xvnc process was listed as Xvnc :10 -geometry..., so I had to use env DISPLAY=:10.0 ....