User interface or in short UI is the means by which a user and a computer system interact this is made possible by the use of input devices and software.
What is the use of a User Interface ?
The purpose of an user interface is to make it easy & enjoyable (user-friendly) for a person to operate a computer machine providing the the best results while being efficient and helping increase productivity.
Hide too technical or hard to execute commands from the user while providing a seamless experience.
IS GUI same as UI ?
Yes, GUI – Graphical User Interface is an extension of user interface. A user interface need not to have graphics like icons and can be text based, whereas GUI has icons, images and other graphics that help create a very user friendly UI.
Today, most of us use GUI’s in one form or an another on our computer and phone screens.
A simple example of UI – is Windows Command Line or Macs Terminal tool, that allow the user to interact with the computer through a text/command based user interface.