What is the Difference beteen UNIX and LINUX OS.

UNIX is a multiuser, multitasking operating system originally developed at Bell Laboratories in 1969 by Ken Thompson, Brian Kernighan and Dennis Richie. Linux was originally developed by Linus Torvalds as a small project while he was a student at the University of Helsinki in Finland. Its written from Scratch, based on the POSIX Standard (Portable Operating System Interface, the open operating interface standard accepted world-wide. It is produced by IEEE and recognized by ISO and ANSI), that defines the Way a UNIX-Like Operating System must work. All Unixes must be POSIX Compliant, no matter if it's Linux, BSD-s, HP-UX, AIX, Solaris, IRIX, etc.

UNIX is a Trademark that originally belonged to Bell Laboratories (AT&T), and has been sold to one company to another with the years (UNIX is what the owner wants it to be). Technically, Linux is not Unix but from the user's point of view, there is little difference between Linux and Unix as both systems follow roughly the same specifications.