Gnome-shell for Ubuntu 15.04 [duplicate]
Install the GNOME Shell 3.14 with this command:
sudo apt-get install gnome-shell
And for GNOME 3.16 or future GNOME versions
sudo add-apt-repository ppa:gnome3-team/gnome3-staging
sudo add-apt-repository ppa:gnome3-team/gnome3
sudo apt-get update
sudo apt-get install gnome-shell