Script to find the default Desktop Environment?

Question

Assume a Linux Desktop Environment system is installed. When powered on and credentials entered, whatever Desktop Environment is started i would consider the default Desktop Environment. The user may pick another Desktop Environment such as KDE or XFCE, but that would not be the default. What is a distribution agnostic snippet of code to find the default Desktop Environment or better yet, the DE last used. The code must run from a remote SSH session or CTRL-ALT-F2 text only console.

The impetus for this question is that i recently emailed the output of nvidia-bug-report.sh to NVIDIA. NVIDIA tech support replied back days later asking "What OS?", "GNOME or KDE?", "What Distribution?" - all meta data that could be automatically collected and catalogued by their own script.

Since the Desktop Environment has crashed, nvidia-bug-report.sh needs to run from a CTRL-ALT-F2 text console or remote SSH session. Clearly, neither of these have the $DESKTOP_SESSION variable. Answer would return one or more items in order of confidence from a list similar to "gnome|kde|mate|cinnamon|lx|xfce|jwm|none".

Would like scripts similar to " How can I get distribution name and version number in a simple shell script? "

Answer 1

Maybe this snippet can help if there's no reliable solution offered :

$ w | awk -vdp=$DISPLAY '($2 ~ dp){gsub(/.*\//, "");print $NF}'

or maybe :

$ qdbus | grep -oPm1 '(kdm|xfce|gnome)'

Another approach using pstree :

$ pstree -H $(pidof X) | grep -oP '(kdm|xfce|gnome)(?=.*?X)'
kdm

And one more :

$ lsof ~/.xsession-errors | grep -oEm1 '(kde|xfce|gnome)'
kde

or a variant :

$ lsof ~/.xsession-errors | awk 'NR==2{print $1;quit}'
startkde