gnome-shell software package provides graphical shell for the GNOME desktop, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gnome-shell
gnome-shell is installed in your system.
Make ensure the gnome-shell package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnome-shell *
You will get with gnome-shell package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | GNOME |
| Package | gnome-shell |
| Version | 3.10.4-0ubuntu5 |
| Description | graphical shell for the GNOME desktop |
| Sub Section | GNOME |