Text-based user interface

In computing, text-based user interfaces (TUI) (alternately terminal user interfaces, to reflect a dependence upon the properties of computer terminals and not just text), is a retronym describing a type of user interface (UI) common as an early form of human–computer interaction, before the advent of modern conventional graphical user interfaces (GUIs). Like GUIs, they may use the entire screen area and accept mouse and other inputs. They may also use color and often structure the display using special graphical characters such as ┌ and ╣, referred to in Unicode as the "box drawing" set. The modern context of use is usually a terminal emulator. From text application's point of view, a text screen (and communications with it) can belong to one of three types (here ordered in order of decreasing accessibility): A genuine text mode display, controlled by a video adapter or the central processor itself. This is a normal condition for a locally running application on various types of personal computers and mobile devices. If not deterred by the operating system, a smart program may exploit the full power of a hardware text mode. A text mode emulator. Examples are xterm for X Window System and win32 console (in a window mode) for Microsoft Windows. This usually supports programs which expect a real text mode display, but may run considerably slower. Certain functions of an advanced text mode, such as an own font uploading, almost certainly become unavailable. A remote text terminal. The communication capabilities usually become reduced to a serial line or its emulation, possibly with few ioctl()s as an out-of-band channel in such cases as Telnet and Secure Shell. This is the worst case, because software restrictions hinder the use of capabilities of a remote display device. Under Linux and other Unix-like systems, a program easily accommodates to any of the three cases because the same interface (namely, standard streams) controls the display and keyboard. See below for comparison to Windows.