GREAT Mac Utility: Onyx
Onyx is a free Mac System Maintenance utility that allows you to tweak (if you have used Tweak UI, you will love this!) hidden parameters of the Dock, Finder, Dashboard, Safari and more. If you want to change the default screen capture format from PNG, this is the application you need. However, the coolest feature is the man page search on the "Unix Utilities" tab: you can enter in any Unix command and you are provided the man page. Even better, should you want to keep this man page for reference, a "Create PDF" button is provided which does just that - it creates a PDF file of the man page displayed on your screen. How cool is that!