Gnome Search Tool is an old “Search For Files” utility. Since Ubuntu turns to Unity Desktop, it’s not installed by default. But it’s one of the most useful utilities, more powerful than the basic search in the Unity Dash. With it you can search for any files in any or all locations.

You can install gnome-search-tool by search & install GNOME Desktop Utilities in Ubuntu Software Center.

Or using:

sudo apt-get install gnome-utils

The package also includes gnome-dictionary, baobab (a disk usage analyser), gnome-system-log, and gnome-screenshot.

After first launch by searching from the Unity Dash, lock it to Launcher.