Alfred is an award-winning app for Mac OS X which boosts your efficiency with hotkeys, keywords, text expansion and more.
The above statement is taken directly from the Alfred website, but it only scratches the surface of what Alfred can do. Besides the search functionality, the ability to integrate with other applications is a real game changer for increasing your efficiency.
On it's own, Alfred is a Spotlight search replacement but it really shines when you add in the Powerpack allowing you to write your own workflows and integrate fully with other applications.
Dash is an API Documentation Browser and Code Snippet Manager.
Using Dash has been one of the biggest optimisations in my programming career. Being able to search through local copies of documentation and "cheat sheets" rather than opening a web browser and searching for what I'm looking for.
Not only does Dash store doc sets, it has the ability to store code snippets, which can be tagged to aid searchability. These code snippets can then be used in other applications thanks to it's autocomplete feature. This is really handy for storing code templates, letting you think about writing feature code and not boiler plate.
Workflows allow you to add cross application functionality to Alfred, enabling more complex tasks and allowing you to automate a number of repetitive tasks. There are a number of these available through the Alfred website but I'm going to be focusing on the Dash integration as that's what I have found most useful.
Provided you have the Alfred powerpack and Dash installed, the workflow is available in the preferences section of Dash.
After double clicking the Alfred icon, the workflow should install it's self.
Under the Downloads section of the Dash preference pane, there are a number of both official and user contributed doc sets available for download. There is a handy search bar that allows you to search across all of the docsets for any particular set you're looking for.
Once installed, the keyword for searching a docset can be customised using the Docsets prefenence pane. The shorter the search term, the faster Alfred will recognise you're searching for a keyword within Dash.