Understanding Linux: Week 1: Linux vs Unix

For the starters, before getting into the intricacies of Linux I decided to clarify properly a confusion between Unix and Linux which I always had (I am being honest). Linux literature everywhere is full of references from Unix and so it is important to understand the difference which is indeed very small. I am pretty sure there are many Linux users out there who never cared to find it out (same as me), this could help them.

In short:

  1. Linux and Unix are two different operating systems kernels.
  2. Linux code is in no way related to Unix.
  3. No, Linux is not built over Unix. Linux is an operating system kernel that is designed like Unix’s kernel.
  4. Unix code is proprietary. Linux code is open source.
  5. Their can be Linux based OS which is not Unix-like. For example Android.
  6. Mac OS X is Unix-based operating system. No, Mac OS X is not based on Linux.

In Detail:

First of all Linux and Unix are not same in anyway. I often hear people telling that Linux is built over Unix which is not true. Linux is a Unix-like operating system but it doesn’t contain any code related to Unix. Unix existed way before the development of Linux started. The development of Linux was widely motivated by the Unix Operating System but it didn’t have any code originally contained in the Unix OS.

It is indeed true that Linux is very similar to Unix. It’s because Linux implements Unix Application Programming Interface (API) defined by POSIX. Linux is classified as mostly POSIX compliant.

You can refer to the references given below for more information. Please comment if you find any mistake.

This article is continuation of  : Understanding Linux : My new blog series.


  1. http://www4.ncsu.edu/~gary/mea443/ppt/443_F10_linux.pdf
  2. http://www.makeuseof.com/tag/linux-vs-unix-crucial-differences-matter-linux-professionals/
  3. http://www.diffen.com/difference/Linux_vs_Unix



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  1. Pingback: Understanding Linux : My new blog series. | Tech and me.

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