In Ubuntu 14.04, you cannot change the window control buttons to the right side of the title bar anymore. If you prefer the window control buttons on the right, or you just don’t like Unity, you can easily go back to the classic Gnome desktop.
NOTE: When we say to type something in this article and there are quotes around the text, DO NOT type the quotes, unless we specify otherwise.
To install the Gnome desktop, press Ctrl + Alt + T to open a Terminal window. Type the following line at the prompt and press Enter. The line is actually two commands. The first command (before the semicolon) updates Ubuntu and the second installs the Gnome desktop.
sudo apt-get update; sudo apt-get install gnome-session-fallback
Type your password when prompted and press Enter.
The progress of the installation displays and then a message displays saying how much disk space will be used. When asked if you want to continue, type a “y” and press Enter.
When the installation is finished, close the Terminal window by typing “exit” at the prompt and pressing Enter.
Click on the system menu in the upper-right corner of the screen and select Log Out to log out of your session.
On the login screen, click the Ubuntu icon.
A list of available desktop environments display. Select the GNOME Flashback option for either Compiz or Metacity.
You are automatically returned to the login screen. Enter your password and press Enter to log in.
The classic Gnome desktop displays with the standard Gnome menus in the upper-left corner of the screen.
The bottom panel is also available and acts as a Taskbar where minimized applications are placed.
Now, you can easily switch between the Gnome and Unity desktop environments.