Elaborate Unix Operating system . 

UNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking system for servers, desktops and laptops.

UNIX systems also have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment. However, knowledge of UNIX is required for operations which aren't covered by a graphical program, or for when there is no windows interface available, for example, in a telnet session.

     There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.

What is Unix ?

• The UNIX operating system is a set of programs that act as a link between the computer and the user.
• The computer programs that allocate the system resources and coordinate all the details of the computer's internals is called the operating system or kernel.
• Users communicate with the kernel through a program known as the shell.
• The shell is a command line interpreter; it translates commands entered by the user and converts them into a language that is understood by the kernel.