In a command line interface, the user types commands using the keyboard to tell the computer to take an action. For example, the more command available in most operating systems will display the contents of a file. Sometimes people call CLI “Console”, but consoles can be GUI, too.
In many graphical user interfaces, the user can use the computer mouse to click on buttons. For example, your web browser may have a Print icon to print this page. Some use a touch screen or other method.
Graphical user interfaces are generally thought more easy to use than command lines. Command lines are faster than graphical user interfaces and can be used to give special commands to the computer.
List of operating systems with graphical user interfaces and command-line interfaces: