This article will describe multiple procedures on how to install various GUI desktop environments on Ubuntu Linux 14.04 LTS (Trusty Thar). The article assumes that no desktop manager nor display manager is currently installed on your system. Furthermore, If the display manager needs to be installed explicitly we will install lightweight XDM. In case that you require different display manager simply replace
xdm package listed in below commands with some alternatives such as GDM, KDM, lightdm etc.
$ sudo apt-get install ubuntu-desktop
$ sudo apt-get install ubuntu-gnome-desktop