Comment by kjellsbells

There was a time when OS X was new that Apple leaned pretty hard into the OS X is UNIX(tm) story. I was working in academia at the time where the Serious Work was being done on SunOS/Solaris and saw print ads aimed at scientists reminding them that OS X was a Real UNIX:

http://xahlee.info/UnixResource_dir/apple_unix_ad.html