Shell – How to detect if DE is Unity or XFCE via shell script

desktop-environmentshell-script

I have a few configuration scripts that I run everytime I install a fresh version of Ubuntu. Recently, however, I migrated to Xubuntu. I would like to use the same script for both distros, since both of them are very similar, but I would also like some parts of the script to be executed only under Xubuntu, and others only under Ubuntu.

My question is: is there a way to tell these distros apart via shell script?

I tried using the lsb-release application, but it seems to not be implemented under Xubuntu; I also tried to read the contents of /etc/*-release, but the contents seem to be similar in both distros.

$ lsb_release 
No LSB modules are available.
$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=15.04
DISTRIB_CODENAME=vivid
DISTRIB_DESCRIPTION="Ubuntu 15.04"

Best Answer

It's impossible to tell Xubuntu from Ubuntu, because they are the same distribution. Xubuntu and Ubuntu are two different installers which set up different desktop environments, but after the initial installation, the administrator can install additional desktop environments. Users can run XFCE after an initial Ubuntu installation or Unity after an initial XFCE installation.

If you wanted to set up some things differently depending on the desktop environment, this is a per-user setting, not a global setting. Since users can run different desktop environments at different times, you should prepare for both (and for KDE, and for twm, etc.).

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Linux – How to Inject Keystrokes via a Shell Script

If you are operating at the X level (as in Gilles' question), then use xdotool like so:

xdotool key KEYSTROKE_SPECIFIER

Where KEYSTROKE_SPECIFIER can be something like "a" or "F2" or "control+j"

EDIT: I missed your response to Gilles' question, sorry. I'll leave this response here as a solution for the X-case.

How to Detect Desktop Environment in a Bash Script

The main problem with checking the DESKTOP_SESSION is that it is set by the display manager rather than the desktop session and is subject to inconsistencies. For lightdm on Debian, the values come from the names of files under /usr/share/xsessions/. DESKTOP_SESSION reflects the desktop environment if a specific selection is made at log in, however the lightdm-xsession is always used the default session.

GDMSESSION is another option, but seems to have a similar predicament (it is the same value as DESKTOP_SESSION for me).

XDG_CURRENT_DESKTOP looks like a good choice, however it is currently not in the XDG standard and thus not always implemented. See here for a discussion of this. This answer shows its values for different distros/desktops, I can also confirm it is currently not available for me on XFCE.

The reasonable fallback for XDG_CURRENT_DESKTOP not existing would be to try XDG_DATA_DIRS. Provided the data files for the desktop environment are installed in a directory bearing its name, this approach should work. This will hopefully be the case for all distros/desktops!

The following (with GNU grep) tests for XFCE, KDE and Gnome:

echo "$XDG_DATA_DIRS" | grep -Eo 'xfce|kde|gnome'

POSIX compatible:

echo "$XDG_DATA_DIRS" | sed 's/.*\(xfce\|kde\|gnome\).*/\1/'

To combine with checking XDG_CURRENT_DESKTOP:

if [ "$XDG_CURRENT_DESKTOP" = "" ]
then
  desktop=$(echo "$XDG_DATA_DIRS" | sed 's/.*\(xfce\|kde\|gnome\).*/\1/')
else
  desktop=$XDG_CURRENT_DESKTOP
fi

desktop=${desktop,,}  # convert to lower case
echo "$desktop"

Best Answer

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