The GUI and CLI

The GUI

GUIs, or Graphical User Interfaces, are probably the most common computer interface you will come across. The name tells you all you need to know - GUIs are any User Interface that uses Graphics! GUIs can use text, icons, images, buttons and all sorts of other widgets to provide output or receive input from a user.

An example of a GUI that you probably use nearly every day is the Windows operating system.

There are many more examples of graphics used in the Windows OS, but above is a basic view of some of the buttons, icons, inputs and outputs in the Windows File Explorer. See if you can identify any other widgets that haven't been circled!

The CLI

CLIs - Command Line Interfaces - used to be the primary way that humans interacted with computers. Nowadays, however, they are much less common, and often only used by professionals or in very old or basic computer systems.

In contrast to a GUI, a CLI uses no graphics at all, only text. Often, a mouse cannot be used to interact with a CLI, leaving a keyboard as the only way to type commands. A CLI doesn't use buttons, images or icons, only text, and can only provide output to the user through text. The user can type commands, or computer instructions, to interact with the CLI. To see an example of a command line, search for "Command Prompt" on your Windows computer.

A CLI is much simpler than a GUI, and is therefore much easier to code. But, its simplicity means that it's much less intuitive for a user to interact with and know what to do. If you don't know any of the valid commands that can be used in a particular CLI, there's very little hope of being able to do anything useful with it.