Operating system

An operating system (commonly abbreviated to either OS or O/S) is an interface between hardware and applications; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer
. The operating system acts as a host for applications that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware.

Graphic User Interface

Users may also interact with the operating system with some kind of software user interface (UI) like typing commands by using command line interface (CLI) or using a graphical user interface (GUI, commonly pronounced “gooey”).

Command line interface

A command-line interface (CLI) is a mechanism for interacting with a computer operating system or software by typing commands to perform specific tasks. This text-only interface contrasts with the use of a mouse pointer with a graphical user interface (GUI) to click on options to select options.

This method of instructing a computer to perform a given task is referred to as "entering" a command: the system waits for the user to conclude the submitting of the text command by pressing the "Enter" key (a descendant of the "carriage return" key of a typewriter keyboard). A command-line interpreter then receives, analyses, and executes the requested command.