How to install GUI desktop on a server?

After installing Ubuntu server how do I install the desktop environment?

Depending on which desktop you wish to install, you install the the meta-package that installs all the necessary packages. You can use apt-get or aptitude to do this.

sudo apt-get install ubuntu-desktop

installs the Unity desktop

sudo aptitude install kubuntu-desktop

would install the KDE desktop

Other desktop meta-packages are xubuntu-desktop, ubuntu-gnome-desktop, lubuntu-desktop, and edubuntu-desktop .

If you wan to install a graphical desktop manager without some of the desktop addons like Evolution and OpenOffice, but continue to use the server flavor kernel use the following command

sudo aptitude install --without-recommends ubuntu-desktop

sudo apt-get install ubuntu-desktop

If you just need to run virtual GUI (GUI exsists but you dont need to see it) on the computer for testing or other purposes.

sudo apt-get install xvnc4viewer

Is a setup I have.

:)

From Ubuntu 20.04, we could use sudo apt install ubuntu-desktop-minimal to minimal install ubuntu-desktop, it removes around 80 packages (and related cruft) from the default install, including Thunderbird, LibreOffice and so on.

The command could replace the old command sudo apt-get install --no-install-recommends ubuntu-desktop or sudo aptitude install --without-recommends ubuntu-desktop.