In Ubuntu Unity, Ctrl+Super+D key combination can be used to hide all windows and show desktop. This tutorial shows how to add ‘Show Desktop’ icon onto Unity launcher in Ubuntu 12.04.
Method 1. Use Myunity
Myunity is a popular unity configuration tool. You can install it from Ubuntu Software Center.
Then launch Myunity, under Desktop tab tick on ‘Active Show Desktop Icon’
- Method 2. Use CompizConfig Settings Manager
Launch terminal from the dash home (or use Ctrl+Alt+T), execute this command to intstall CCSM:
sudo apt-get install compizconfig-settings-manager
Then launch CCSM and click to go into Ubuntu Unity Plugin, at Experimental tab scroll down and tick on ‘Show Desktop Icon in the launcher’