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How Unix is Mac OS X?

People always said ubuntu, linux is UNIX based OS, then how about mac os x? from mac os x terminal i can see most of the unix command are available does it mean mac os also built on UNIX?

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migrated from Jan 11 '10 at 13:48

This question came from our site for professional and enthusiast programmers.

marked as duplicate by Arjan, BinaryMisfit Jan 11 '10 at 16:04

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

What do you expect from an answer? – Marco van de Voort Jan 11 '10 at 13:46
Duplicate of "How Unix is Mac OS X?" at – Arjan Jan 11 '10 at 14:58


Indeed 10.5 and 10.6 are Unix (tm) certified which linux is not.

To be more specific, Mac OS X is built on Darwin---a derivative of BSD---running on a Mach microkernel.

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URL/Reference? I know they were busy doing it (Apple being Unix licensee already because of A/UX), didn't know the outcome. – Marco van de Voort Jan 11 '10 at 13:45
UNIX 03 certified, indeed. 10.5: and 10.6: – Carmine Paolino Jan 11 '10 at 13:51

Mac OS X is based on the Berkeley Software Distribution. BSD is Unix.

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Indeed it is:

Mac OS X, whose "X" represents the Roman numeral for "10" and is a prominent part of its brand identity, is a Unix-based operating system, built on technologies developed at NeXT >between the second half of the 1980s and Apple's purchase of the company in late 1996. Its sixth release Mac OS X v10.5 "Leopard" gained UNIX 03 certification while running > on Intel processors.


As another poster stated it's also Unix certified:

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Mac OS X is a genetic UNIX (being a descendant of NEXTSTEP and ultimately BSD, a genetic UNIX).

It's also a UNIX-like OS (being UNIX-like).

See the relationship to UNIX and Linux here:

Note that Linux is UNIX-like but no genetic or trademark UNIX. Mac OS X is both a trademark and a genetic UNIX.

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