Is Linux Unix?
No. However, Linux is often called "Unix-like" because it functions in much the same way as Unix. For instance, it uses a command-line interface. Also, many of its basic commands have the same name and serve the same purpose, like those found in Unix. However, the Linux operating system is not directly descended from any of Unix's code. Additionally, it does not comply with the official single Unix specification technical standard as defined by the Open Group.
The Open Group, which controls the Unix trademark, does not approve of the term "Unix-like" or any other hyphenation of the word "Unix."