Mac OS X is BSD, while linux is gnu. The two are similar, but different. They also use different file systems:
Most often, its a human using a Mac, and a linux machine running services and managing networks. There are a few things that I need both linux and Macs to do for me:
I know there are many other ways to accomplish those goals, but I prefer to use tools that come standard on both platforms.
Alternative Security Options:
Other cool Mac OS X and unix related stuff:
Put unison settings in .unison, NOT Library/Application Support/Unison.
Beyond what I would do to make Mac more like linux:
These pages talk about installing more command line utils to make bsd more like linux.