HUD is nice feature which is available in Ubuntu 12.04 Precise Pangolin. With HUD you can easily handle commands without touching mouse. HUD added by default in Ubuntu 12.04 Precise Pangolin but only in Unity 3D with compiz. HUD is not added for Ubuntu 2D but you can install HUD on Ubuntu Unity 2D easily with PPA. HUD for Unity 2D is not officially available.
Installation of HUD in Ubuntu Unity 2D, open Terminal and enter following commands:
If you found any bug Report here.
sudo add-apt-repository ppa:unity-team/ppa sudo apt-get update sudo apt-get dist-upgrade