When I look at it, I basically see NeXTSTEP which is UNIX... I see a lot of OS X is BSD, or, OS X is Darwin + BSD, all I see is NeXTSTEP with a worse interface...
When I say OX is literally UNIX, the emphasis is on the word 'literally'. To be classified as a UNIX system, meaning that an OS maker can use the UNIX trademark, the system have to be certified by the The Open Group.
BSD was UNIX, yet neither of it's 2 prevalent derivatives (FreeBSD and OpenBSD) has applied for certification. They are classified as Unix-like; the same is true for any Linux distribution.
To some people, this may be semantics, but one of the reasons that drew me to OSX was the certification.
yes, I got the reference. I was talking about personal impressions, I was not clear about it though, sorry. I still remember when they (Apple) run an ad showing a powerbook running Mac OS X saying "Send other UNIX to /dev/null", how excited I was at the time :-P
Almost all of the userland command-line tools are from BSD. The most important exception is clang which is independent (though Apple has historically been the biggest contributor).
