I'm watching the Cybrary Linux+ Cert course and all throughout the lessons the instructor keeps referring to MacOS and Apple related software as being based on Linux. I thought MacOS was built on BSD and Apple software was mostly proprietary but at its core based on open source projects like Bonjour. I'm cringing because I *think* what he means is "Unix-like systems" and I'm a little disturbed that he might not know the difference between BSD and Linux. Maybe it's just for simplicity's sake though... I hope.