How to show the day of the week on the desktop date with Ubuntu 20.04 LTS

To add on to the other excellent answers, it's possible to get the following error/warning while changing org.gnome.desktop.interface settings:

GLib-GIO-Message: Using the 'memory' GSettings backend.  Your settings will not be saved or shared with other applications.

the issue was discussed here and the general answer is that environment variable GIO_EXTRA_MODULES need to point to the location of gio modules like so:

export GIO_EXTRA_MODULES=/usr/lib/x86_64-linux-gnu/gio/modules/

To make the above permanent, this needs to be put in .bashrc

After doing so, org.gnome.desktop.interface will be saved.

Install gnome-tweaks

after installing it open the app, find menu item named "Top Bar" and then enable weekday.

gnome-tweaks is a wonderful tool that should be installed after installing synaptic but before installing anything else.

You can try this in the terminal.

gsettings set org.gnome.desktop.interface clock-show-date true
gsettings set org.gnome.desktop.interface clock-show-seconds true
gsettings set org.gnome.desktop.interface clock-show-weekday true

To show the weekday in addition to the date and time in Ubuntu 20.04, use the command line tool called "gsettings".

It's a good idea to view your current settings first. So open the terminal and run this command:

gsettings list-recursively org.gnome.desktop.interface

It will return various Gnome interface settings, and the one you are interested in is "clock-show-weekday" (with the value "false").

Set the "clock-show-weekday" to "true" by running this command:

gsettings set org.gnome.desktop.interface clock-show-weekday true

Once you hit Enter, you will will see the weekday displayed with the weekdays shown.