I typically use Dash to search for programs and, less often, files. The default behaviour of Unity Dash is to return thousands of results among not only your documents, but also online shops, search engines, social networks, music and so on.

I found this very annoying and redundant – since the side lanucher only has room for that many icons, I use the dash search to launch programs I need, not for browsing the Internet. Therefore I found a few tricks to limit the search to local programs and files.

1. Disable online search results
Go to “System Settings… / Security & Privacy / Search” and set “Include online search result” to OFF.
(more at techrepublic.com)

2. Disable filters, scopes, lens applications

All different types of suggestions come from a helper application; removing most of them will clean the results.
The list of installed components can be printed with

$ dpkg -l | grep scope
$ dpkg -l | grep lens

The only ones really needed are:

  • libunity-scopes-json-def-desktop
  • unity-scope-home
  • unity-scopes-master-default
  • unity-scopes-runner
  • unity-lens-applications
  • unity-lens-files

I also usually keep those ones:

  • unity-scope-calculator
  • unity-scope-manpages
  • unity-lens-music

All the others can be removed with a single command:

$ sudo apt-get purge name-1 name-2 ...

(more on this page on AskUbuntu.com)