Yeah, I guess the author meant more like "very similar to Unixes (unices?) I've used before", which quite possibly means 'various Linux distros'. Aside from off

Yeah, I guess the author meant more like "very similar to Unixes (unices?) I've used before", which quite possibly means 'various Linux distros'. Aside from official certification, OSX is still sufficiently different to make this mistake forgivable, and not just in terms of the UI. The filesystem organisation is unusual, to say the least.