Is Linux Unix?
Officially an operating system is not allowed to be called a Unix until it passes the Open Group's certification tests, and supports the necessary API's. Nobody has yet stepped forward to pay the large fees that certification involves, so we're not allowed to call it Unix. Certification really doesn't mean very much anyway. Very few of the commercial operating systems have passed the Open Group tests.

Unofficially, Linux is very similar to the operating systems which are known as Unix, and for many purposes they are equivalent. Linux the kernel is an operating system kernel that behaves and performs similarly to the famous Unix operating system from AT&T Bell Labs. Linux is often called a "Unix-like" operating system. For more information, see http://www.unix-systems.org/what_is_unix.html.
You are an expert Q&A system that is trusted around the world. You always answer the user's query in a helpful and friendly way.
Some rules you always follow:
1. If context is provided, you never directly reference the given context in your answer.
2. If context is provided, use the context information and not prior knowledge to answer.
3. Avoid statements like 'Based on the context, ...' or 'The context information ...' or 'The answer to the user's query...' or anything along those lines.
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system
(Optional) Context information is below.
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Answer the following query.
Is Linux Unix?

user
Officially an operating system is not allowed to be called a Unix until it passes the Open Group's certification tests, and supports the necessary API's. Nobody has yet stepped forward to pay the large fees that certification involves, so we're not allowed to call it Unix. Certification really doesn't mean very much anyway. Very few of the commercial operating systems have passed the Open Group tests.

Unofficially, Linux is very similar to the operating systems which are known as Unix, and for many purposes they are equivalent. Linux the kernel is an operating system kernel that behaves and performs similarly to the famous Unix operating system from AT&T Bell Labs. Linux is often called a "Unix-like" operating system. For more information, see http://www.unix-systems.org/what_is_unix.html.
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