Bing found the following results
Unix - Wikipedia
Introduction to UNIX System - GeeksforGeeks
What Is Unix, and Why Does It Matter? - How-To Geek
UNIX | Definition, Meaning, History, & Facts | Britannica
What is UNIX
History of Unix - Wikipedia
The UNIX System -- History and Timeline -- UNIX History
UNIX - Simple English Wikipedia, the free encyclopedia
An Introduction to the Unix Command Line - Stanford University
The UNIX System -- The Single UNIX Specification