Identify and restart (gnome-classic) window manager on RHEL7

Question

I pride myself on keeping my system up and running a long time between restarts. I have a long running RHEL7 workstation. Occasionally (usually if it has been running continuously for a month) the window manager crashes. By crashes I mean the windows are 'visible' but have no title bars, menus etc. The mouse pointer can be moved but the focus cannot be changed.

I can however switch to a terminal session using Alt-F1 etc.

On previous systems I was able to restart the window manager using something like:

metacity --replace

or

compiz --replace

This would restore my session without me even having to logout. However, I am not clear which window manager is even running. How can I find out?

Note that I know you can restart the display manager using:

systemctl restart display-manager

but that starts a new session and requires you to log in again. I would like to be able to restart just the crashed wm process without doing this.

I think under the hood this is still gnome3 using wayland, mutter or some such. Is there actually a separate window manager I can restart at all any more? and if not why not?

Answer 1

Yes. There is still a window manager and you can restart it. You can confirm you are running gnome-classic as below:

>set | grep DESK
DESKTOP_SESSION=gnome-classic
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
IMSETTINGS_INTEGRATE_DESKTOP=yes
XDG_CURRENT_DESKTOP=GNOME-Classic:GNOME
XDG_SESSION_DESKTOP=gnome-classic

You can identify the version (mine was 3.22.2) by typing "about" in activities as suggested here:

https://help.gnome.org/users/gnome-help/stable/gnome-version.html.en

You can use wmctrl to identify the window manager used. This is missing from the standard redhat repos at present (https://bugzilla.redhat.com/show_bug.cgi?id=1326876) but available from the nux-dextop repo (https://li.nux.ro/repos.html)

>wmctrl -m
Name: GNOME Shell
Class: N/A
PID: N/A

then:

>ps aux | grep -i shell

shows gnome-shell is runnning.

>man gnome-shell

shows that gnome-shell supports the --replace argument and so can be used to restart the window manager as before.

gnome-shell --replace &