Synapse is a semantic launcher written in Vala that you can use to start applications as well as find and access relevant documents and files by making use of the Zeitgeist engine.
Install synapse in ubuntu using ppa
Open the terminal and run the following commands
sudo add-apt-repository ppa:synapse-core/ppa
sudo apt-get update
sudo apt-get install synapse
* pressing "Home" or "End" on your keyboard will select the first or the last search result?
* pressing "Tab" will let you in/out the Action selection
* when you're selecting an Action you can type to apply a filter on the actions' list
* pressing "Left" or "Right" keys will change the category of results
* pressing "Shift+Enter" will execute the action trying to keep Synapse opened to give you the opportunity to execute other matches