Is there a simple linux command that will tell me what my display manager is?

Question

Is there a simple linux command that will tell me what my display manager is?

I'm using Xfce. Are different desktop environments usually affiliated with different display managers?

Answer 1

Unfortunately the configuration differs for each distribution:

Debian/Ubuntu

/etc/X11/default-display-manager

RedHat & Fedora

/etc/sysconfig/desktop

see Fedora docs: Switching desktop environments

OpenSuSe

/etc/sysconfig/displaymanager

Answer 2

If you are using a systemd based distribution, this command will give the name of the display manger currently configured because you may have more than one display manager installed.

grep 'ExecStart=' /etc/systemd/system/display-manager.service

Output will be something like

ExecStart=/usr/bin/mdm

Looks like I am using mint display manager.

Answer 3

If you're using systemd, then

systemctl status display-manager

Will display the name and status of the active display manager service on your machine.

Answer 4

There isn't. The display manager is not necessarily related to anything else that's running on the same X server. The display manager runs before you log in; it's chosen by the system administrator. Everything else (window manager, session manager, desktop environment, …) is chosen by the user. There doesn't even have to be a display manager: if you log in in text mode and start the GUI with startx, no display manager is involved.

You can check which display manager is the default one on your system. This will only give the right answer under some common but not universal assumptions. If you manually ran a different manager for whatever reason, this method won't tell you.

A good bet is to find out the process ID of the X server: its parent process is probably a display manager, if there is one. This requires that your clients are running on the same machine as the X server. lsof /tmp/.X11-unix/X${DISPLAY#:} will show the X server process (assuming the X sockets live in /tmp/.X11-unix).

x=$(lsof -F '' /tmp/.X11-unix/X0); x=${x#p}
ps -p $(ps -o ppid -p $x)

(Explanation: lsof -F '' prints output like p1234. The -F option means a machine-parseable output format, and '' means to only print the PID, with the letter p before it. x=${x#p} strips off the initial letter p. The last line obtains the PID of the parent of the X server (ps -o ppid -p $x), and calls ps to show information about that parent process.)

Some distributions allow installing multiple display managers. There'll only be a single one running unless you have a multiseat system though. To list all installed display manager packages under Debian and derivatives:

aptitude -F %p search '~i ~P^x-display-manager$'

or

</var/lib/dpkg/status awk '
    /^Package: / {package = $2}
    /^Provides: .*x-display-manager/ {print package}'

Answer 5

The display manager name should be in DESKTOP_SESSION

echo $DESKTOP_SESSION

returns "gnome" for me.

EDIT
You're right. They're going back and forth on that on XFCEs bugzilla so it probably isn't very reliable.

Answer 6

Like @Gilles said, the display manager will start your desktop environment.

According to the Debian Wiki, mostly these end with dm, only exceptions are gdm3 and slim.

So this should suffice for most of people's needs:

ps auxf | awk '{print $11}' | \grep -E '(dm|slim|gdm3)$'

Or to be sure, it exists as a parent process, and is not forked (except from the init system):

ps auxf | awk '{print $11}' | \grep -E "^/.*(dm|slim|gdm3)$"

Answer 7

Try using this command

systemctl |grep "Display Manager"

This will provide below output.

[anil@localhost Desktop]$ systemctl |grep "Display Manager" xdm.service loaded active running X11 Display Manager

Now you can see xdm.service listed just above loaded active running and that is your Display Manager

Answer 8

You can do this via a third-party script called screenfetch

Screenfetch is a bash script available for Linux that displays system information alongside the ASCII version of the Linux distribution Logo of the system

Install via package manager sudo apt-get install screenfetch (assuming you're on Debian variants)

and just run screenfetch In your terminal

Project link https://github.com/KittyKatt/screenFetch

Answer 9

After you enable the display-manager.service, a symlinked file to the specified or default display manager in use -- as you might have multiple one on the same desktop environment -- should be at /etc/systemd/system/display-manager.service

file /etc/systemd/system/display-manager.service

This method reliably worked out for me on ubuntu-20 LTS.

Answer 10

Another systemd approach.

This one uses the show command to filter out a property of the display-manager service:

➜ systemctl --property=Id,Description show display-manager.service
Id=sddm.service
Description=Simple Desktop Display Manager

Answer 11

As already mentioned, there is a lot of confusion in this thread. The original question is what display manager, not desktop manager or window manager. I'm currently running Xfwm4 which is Xfce window manager, and lxdm which is lightweight X11 display manager (from LXDE, not Xfce). You should be able to see what display manager you are using via htop. You've probably long since discovered the answer over the past 4 years :)

Answer 12

In some case, wmctrl could help. This utility is compatible with a lot of windows managers.

wmcrt -m 

should display the name of the currently used window manager.