UNIX: Basic UNIX commands you should know! Beginners guide.
Unix & Linux - Fast Tech Skills
Its a UNIX system! I know this!
Introduction to UNIX (OS) | UNIX Tutorial
Unix is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, development starting in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others.