(
Character-based
User
Interface) A method for interacting with the computer that displays a fixed set of rows and columns on screen with monospaced characters and a single font. Common in the days of mainframe and minicomputer terminals as well as the early days of personal computers (DOS, Apple II, CP/M, etc.), CUI-based computers were operated by the keyboard, using a combination of function keys, key sequences and by typing in commands in a prescribed syntax. CUIs were superseded by GUIs (graphical user interfaces), and although character-based displays are no longer common, command line interfaces are still included in all major operating systems. Contrast with
GUI.