Linux find running display manager

In GNU/Linux, if you ever need to know what your currently running display manager is, here is how you can find it:

x="$( sudo lsof -F '' /tmp/.X11-unix/X0 | head -n1 )" ; x="${x#p}"
display_manager="$( ps -p $( ps -o ppid -p ${x} | tail -n +2 ) -ho command )"
thisdm="$( basename "${display_manager}" )"




Find running X sessions


{ ps -eo pid,command | awk '/-session/ {print $1}' | while read thispid; do cat /proc/${thispid}/environ | tr '\0' '\n' | grep "DISPLAY" | sed -e "s/^/${thispid} $( stat -c '%U' /proc/${thispid}/comm ) $( basename $( readlink -f /proc/${thispid}/exe ) ) /;"; done; } 2>/dev/null | grep -iE "xfce|cinnamon"


I was working on a shell script that affects the running desktop environments. In order to find the running processes, owners, executable, and display session, I whipped up this one-liner.

Obviously here, I limit my searches to specific types of desktop environments. I was getting a dbus-daemon and at-spi2-registryd which I neither understand nor care about, so I added the regular expression search at the end. Feel free to modify for your own use.

Example output:

$ { ps -eo pid,command | awk '/-session/ {print $1}' | while read thispid; do cat /proc/${thispid}/environ | tr '\0' '\n' | grep "DISPLAY" | sed -e "s/^/${thispid} $( stat -c '%U' /proc/${thispid}/comm ) $( basename $( readlink -f /proc/${thispid}/exe ) ) /;"; done; } 2>/dev/null | grep -iE "xfce|cinnamon"
1791 bgstack15-local xfce4-session DISPLAY=:0

X forwarding for virt-manager to Windows

Story time! When I was working on my virtual environment, I rebooted my main desktop. So I was stuck using my Windows desktop for a minute, and I wanted to work on my virtual machines.

I decided to do some X forwarding, which for virt-manager on CentOS 7 needs some special steps.

On the server

The first thing is to install virt-manager. You also will need a piece of software named xauth, and some special fonts.

yum install -y virt-manager xauth dejavu-\*fonts


On the client

On the Windows client, you should install an X server. I picked Xming. It also needs it fonts installed.

Run Xming.

Connect to server with PuTTY. You will need to configure PuTTY to allow X forwarding, and to use the right X server.

Screenshot of Putty configuration screen showing X11 forwarding options
Telling PuTTY to allow X11 forwarding to localhost:0


Unfortunately, my keyboard input to the virtual machine does not work when I have it configured with a spice display. But it works when I use a vnc display. See for a closed bug report that has similar symptoms to this problem.

virt-manager settings of a virtual machine, showing where to change display to VNC server type.
Setting on virtual machine of VNC server or spice server.



  7. PuTTY