Also known as UN*X or *nix. An operating system that is similar in many characteristics to a Unix system, its application behaves like an equate Unix command or shell. Aside from the obvious Unix features, they also have direct source code and the documentation officially states that they are Unix-like.
|First released||late 1970s|
|Developed by||Idris among others|
Not all Unix-like systems are free, some of them are proprietary.