If unix and linux are supposed to be so different, why are they sharing a category on this web site? This pairing of two OS on one stackexchange topic makes it seem that they are indistinguishable and a question concerning Linux can apply to Unix.

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    Linux is a Unix-like operating system. There are many many similarities between the two, many solutions will apply equally to both.
    – terdon Mod
    Commented Oct 1, 2013 at 18:01
  • Just because some questions can be relevant to both Unix and Linux, doesn't mean all questions about one apply equally to the other. I think it's clear that there is a lot of overlap. Commented Oct 1, 2013 at 20:44
  • see also unix.stackexchange.com/questions/4091/is-linux-a-unix
    – strugee
    Commented Oct 11, 2013 at 23:27

3 Answers 3


Unix is not an operating system, it's a family of operating systems. Linux is not an operating system, it's the kernel found in a number of Unix-like and non-Unix-like operating systems.

There's as much difference between one non-Linux-based Unix system and the next as between one Linux-based one and the next, but they all share very similar interfaces and have a lot concepts in common.

It makes sense to have both. I find the Unix & Linux name confusing and misleading myself though because it mixes operating systems and kernels and seem to imply that things like GNU would be off-topic and that your TV, printer or smart phone running Linux would be on-topic. Unix-like operating systems would have been a better name IMO.

I suppose the name was chosen because few people suspect Debian or Fedora for instance are Unix-like operating systems, while more may have heard that they are built around a Linux kernel (though for Debian, Linux is not the only supported kernel).

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    Kernel Panic would have been the best name IMO, but then they stopped doing fancy names. Commented Oct 1, 2013 at 22:04
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    Or we could have called it Largely compliant with POSIX operating systems and software that will run in that environment Commented Oct 1, 2013 at 22:09
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    UNIX is an operating system, originally from AT&T Bell Laboratories, later sold to Novell. Wikipedia a history of Unix that explains fairly well.
    – derobert
    Commented Oct 17, 2013 at 13:44
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    Name was probably also chosen to get those sweet, sweet search engine clicks. Pragmatic.
    – phk
    Commented Jan 8, 2017 at 22:46

The name is a useful reminder that GNU/Linux is not the only unix-like environment around and that, unless a particular flavour of unix or particular Linux distribution is mentioned in the question, answers should be careful to at least make note of any non-POSIX features used in the answer or provide both POSIX and non-POSIX versions of the answer.

e.g. if your answer includes a shell script that uses features only available in bash, then mention that it is a bash script, not a sh script. Similarly, if you use features of sed or grep or some other tool that are only available in the GNU versions of that tool, then mention it. Bonus points for providing a variation of your answer that works using only POSIX features of the tool(s).


GNU/Linux is a UNIX clone. UNIX is a big family and consist other family such as BSD, systemV, SVR and so on. for more information you can visit: unix history

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    note: GNU's Not UNIX! also, what is SVR?
    – strugee
    Commented Oct 11, 2013 at 23:26

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