Ubuntu Desktop comes with GNOME as the default desktop environment. Ubuntu Desktop also has the necessary GNOME applications and tools, configured for the Ubuntu experience.
If you're already running Ubuntu, you can still install KDE, or even the complete Kubuntu desktop on top of your Ubuntu or GNOME desktop. It can be done by installing the appropriate meta package via apt at the terminal.
$ sudo apt update [sudo] password for user: Hit:1 http://ports.ubuntu.com/ubuntu-ports kinetic-security InRelease Hit:2 http://us.ports.ubuntu.com/ubuntu-ports kinetic InRelease Hit:3 http://us.ports.ubuntu.com/ubuntu-ports kinetic-updates InRelease Hit:4 http://us.ports.ubuntu.com/ubuntu-ports kinetic-backports InRelease Reading package lists... Done Building dependency tree... Done Reading state information... Done All packages are up to date.
$ sudo apt dist-upgrade --assume-yes Reading package lists... Done Building dependency tree... Done Reading state information... Done Calculating upgrade... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
This will install a basic KDE Plasma packages and experience on your Ubuntu system. To install a more complete KDE Plasma experience, you can install kubuntu-desktop meta package instead.
Select Ok using the [TAB] key and press [ENTER] to continue on the Package configuration menu if you're first presented with the following screen. You'll get this screen if you're using a low resolution monitor and/or not running terminal in full screen.
SDDM is the default display manager for Kubuntu/KDE.
$ sudo reboot
Select Ubuntu or Ubuntu on Wayland (Wayland) if you want to log in to GNOME desktop environment.
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