We have covered many tools which perform or schedule system shutdown in Windows, WinDown and Shutdown Agent are two examples. GShutdown is a tool for Ubuntu which performs and schedules system shutdown and restart.
In order to install this application, open the terminal and run the following command:
sudo apt-get install gshutdown
Once the installation is completed, go to the Applications->Accessories->Gshutdown to launch it. Specify the time to shutdown or restart your computer and hit the Start button.
You will find its icon located in the system tray (Known as Panel in Linux) for faster access.
It works on Gnome, KDE and XCF desktop environments. Enjoy!