Editing Text-based user interface

{{short description|Type of interface based on outputting to or controlling a text display}}
{{distinguish|Command-line interface}}
{{refimprove|date=September 2014}}
[[File:Midnight Commander (2005) en.png|thumb|300px|Some [[file manager]]s implement a TUI (''here: [[Midnight Commander]]'')]]
[[File:Vim-%28logiciel%29-console.png|thumb|300px|[[Vim (text editor)|Vim]] is a very widely used TUI text editor]]

In [[computing]], '''text-based user interfaces''' ('''TUI''') (alternately '''terminal user interfaces''', to reflect a dependence upon the properties of [[computer terminal]]s 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 bitmapped displays and modern conventional [[graphical user interface]]s (GUIs). Like modern GUIs, they can use the entire [[Electronic visual display|screen]] area and may accept [[computer mouse|mouse]] and other inputs. They may also use color and often structure the display using [[box-drawing character]]s such as ┌ and ╣. The modern context of use is usually a [[terminal emulator]].
<!-- [[VisiCalc]] and the [[Emacs]] and [[Vi (text editor)|vi]] [[visual editor]]s are the earliest examples of TUIs. -->

== Types of text terminals ==
From [[console application|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 computer]]s and [[mobile device]]s. 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&nbsp;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 [[raster font|font]] uploading<!-- BTW what about raw keyboard input? -->, 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 data|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 kernel|Linux]] and other [[Unix-like]] systems, a program easily [[graceful degradation|accommodates]] to any of the three cases because the same interface (namely, [[standard streams]]) controls the display and keyboard. See [[#Windows|below]] for comparison to Windows.

Many [[#See also|TUI programming libraries]] are available to help developers build [[Console application|TUI applications]]. 

== On ANSI-compatible terminals ==
[[American National Standards Institute]] (ANSI) standard [[ANSI X3.64]] defines a standard set of [[escape sequence]]s that can be used to drive terminals to create TUIs (see [[ANSI escape code]]). Escape sequences may be supported for all three cases mentioned in the above section, allowing arbitrary [[text cursor|cursor]] movements and color changes.
However, not all terminals follow this standard, and many non-compatible but functionally equivalent sequences exist.

{{clear}}

== Under DOS and Microsoft Windows ==
[[File:Fdedit.png|thumb|300px|The [[FreeDOS]] Edit user interface]]
On [[IBM Personal Computer]]s and [[IBM PC compatible|compatibles]], the Basic Input Output System ([[BIOS]]) and [[DOS]] system calls provide a way to write text on the screen, and the [[ANSI.SYS]] driver could process standard ANSI escape sequences. However, programmers soon learned that writing data directly to the [[screen buffer]] was far faster and simpler to program, and less error-prone; see [[VGA-compatible text mode]] for details. This change in programming methods resulted in many DOS TUI programs. {{anchor|Windows}}The [[Windows console]] environment is notorious for its emulation of certain EGA/VGA text mode features, particularly random access to the text buffer, even if the application runs in a window. On the other hand, programs running under Windows (both native and DOS applications) have much less control of the display and keyboard than Linux and DOS programs can have, because of aforementioned Windows console layer.

[[File:itmouse.png|thumb|300px|left|Mouse cursor in [[Impulse Tracker]]. A more precise cursor (per-pixel resolution) was achieved by regenerating the glyphs of characters used where the cursor was visible, at each mouse movement in real-time.{{citation needed|date=December 2011}}]]

Most often those programs used a blue background for the main screen, with white or yellow characters, although commonly they had also user color customization. They often used [[box-drawing character]]s in IBM's [[code page 437]]. Later, the interface became deeply influenced by [[graphical user interface]]s (GUI), adding [[pull-down menu]]s, overlapping [[window (computing)|windows]], [[dialog box]]es and [[GUI widget]]s operated by [[mnemonics (keyboard)|mnemonics]] or [[keyboard shortcut]]s. Soon [[computer mouse|mouse]] input was added&nbsp;– either at text resolution as a simple colored box or at graphical resolution thanks to the ability of the [[Enhanced Graphics Adapter]] (EGA) and [[Video Graphics Array]] (VGA) display adapters to [[VGA-compatible text mode#Fonts|redefine the text character shapes by software]]&nbsp;– providing additional functions.

Some notable programs of this kind were [[Microsoft Word]], [[DOS Shell]], [[WordPerfect]], [[Norton Commander]], [[Turbo Vision]] based [[Borland]] [[Turbo Pascal]] and [[Borland Turbo C|Turbo C]] (the latter included the [[conio.h|conio]] [[library (computer science)|library]]), [[Lotus 1-2-3]] and many others. Some of these interfaces survived even during the [[Microsoft]] [[Windows 3.1x]] period in the early 1990s. For example, the [[Microsoft C]] 6.0 compiler, used to write true GUI programs under [[16-bit]] Windows, still has its own TUI.

Since its start, [[Microsoft Windows]] includes a console to display DOS software. Later versions added the [[Windows console]] as a native interface for [[command-line interface]] and TUI programs. The console usually opens in window mode, but it can be switched to full, true text mode screen and vice versa by pressing the [[Alt key|Alt]] and [[Enter key|Enter]] keys together. Full-screen mode is not available in Windows Vista and later, but may be used with some workarounds.<ref>[http://social.technet.microsoft.com/Forums/en/w7itprohardware/thread/3cc6994e-cbc2-4844-b040-a3c8385c69a5 cmd prompt full screen in Windows 7]. Social.technet.microsoft.com. Retrieved on 2013-06-15.</ref>
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[[Windows Terminal]] is a [[Tabbed|multi-tabbed]] [[terminal emulator]] that [[Microsoft]] has developed for [[Windows 10]] and later<ref>{{cite web|url=https://www.theverge.com/2019/5/6/18527870/microsoft-windows-terminal-command-line-tool|title=Microsoft unveils Windows Terminal, a new command line app for Windows|first=Tom|last=Warren|date=May 6, 2019|website=The Verge}}</ref> as a replacement for [[Windows Console]]. 

The [[Windows Subsystem for Linux]] which was added to Windows by [[Microsoft]] in 2019, supports running [[Linux]] text-based apps on Windows, within [[Windows console]], [[Windows Terminal]], and other Windows-based terminals.

== Under Unix-like systems ==
[[File:XFdrake.png|thumb|300px|Snapshot of 'XFdrake', a TUI used in [[Mandriva Linux]] to configure the graphical system]]
[[File:Btop screenshot.png|thumb|300px|btop - task manager utility for Linux and other unix-like OS]]
In [[Unix-like]] operating systems, TUIs are often constructed using the terminal control [[library (computer science)|library]] ''[[curses (programming library)|curses]]'', or ''[[ncurses]]'' (a mostly compatible library), or the alternative ''[[S-Lang]]'' library. The advent of the ''curses'' library with [[Berkeley Software Distribution|Berkeley Unix]] created a portable and stable API for which to write TUIs. The ability to talk to various [[text terminal]] types using the same [[API|interfaces]] led to more widespread use of "visual" Unix programs, which occupied the entire terminal screen instead of using a simple line interface. This can be seen in [[text editor]]s such as [[Vi (text editor)|vi]], [[Email client|mail clients]] such as [[pine (email client)|pine]] or [[mutt (email client)|mutt]], system management tools such as [[System Management Interface Tool|SMIT]], [[SAM (HP-UX)|SAM]], [[FreeBSD]]'s [[Sysinstall]] and [[web browser]]s such as [[lynx (web browser)|lynx]]. Some applications, such as [[w3m]], and older versions of pine and [[Vi (text editor)|vi]] use the less-able [[termcap]] library, performing many of the functions associated with [[curses (programming library)|curses]] within the application. Custom TUI applications based on ''widgets'' can be easily developed using the [[Dialog (software)|dialog]] program (based on [[ncurses]]), or the [[Newt (programming library)|Whiptail]] program (based on [[S-Lang]]).

In addition, the rise in popularity of [[Linux]] brought many former DOS users to a Unix-like platform, which has fostered a DOS influence in many TUIs. The program [[minicom]], for example, is modeled after the popular DOS program [[Telix]]. Some other TUI programs, such as the [[Twin (windowing system)|Twin]] desktop, were [[ported]] over.

Most Unix-like operating systems (Linux, FreeBSD, etc.) support [[virtual console]]s, typically accessed through a Ctrl-Alt-F key combination. For example, under Linux up to 64 consoles may be accessed (12 via function keys), each displaying in full-screen text mode.

The [[free software]] program [[GNU Screen]] provides for managing multiple sessions inside a single TUI, and so can be thought of as being like a [[window manager]] for text-mode and command-line interfaces. [[Tmux]] can also do this.

The proprietary [[macOS]] [[text editor]] [[BBEdit]] includes a ''shell worksheet'' function that works as a full-screen shell window. The [[free software|free]] [[Emacs]] text editor can run a shell inside of one of its buffers to provide similar functionality. There are several shell implementations in Emacs, but only <code>ansi-term</code> is suitable for running TUI programs. The other common shell modes, <code>shell</code> and <code>eshell</code> only emulate command lines and TUI programs will complain "Terminal is not fully functional" or display a garbled interface. The [[free software|free]] [[Vim (text editor)|Vim]] and [[Neovim]] text editors have terminal windows (simulating [[xterm]]). The feature is intended for running jobs, parallel builds, or tests, but can also be used (with window splits and tab pages) as a lightweight terminal multiplexer.

== OpenVMS ==
VAX/VMS (later known as [[OpenVMS]]) had a similar facility to ''curses'' known as the Screen Management facility or SMG.  This could be invoked from the command line or called from programs using the SMG$ library.<ref>{{cite web|url=http://h30266.www3.hpe.com/odl/vax/opsys/vmsos73/vmsos73/5935/5935pro_contents.html|title=OpenVMS RTL Screen Management (SMG$) Manual|date=2001|access-date=2021-01-01|website=hpe.com}}</ref>

== Oberon ==
[[File:OberonScreen.PNG|thumb|300px|Screenshot of the desktop of an Oberon System showing an image and several text viewers]]
Another kind of TUI is the primary interface of the [[Oberon (operating system)|Oberon operating system]], first  released in 1988 and still maintained. Unlike most other text-based user interfaces, Oberon does not use a text-mode console or terminal, but requires a large bit-mapped display, on which text is the primary target for mouse clicks. Analogous to a [[Hyperlink|link]] in [[hypertext]], a command has the format <code>Module.Procedure ''parameters''&nbsp;~</code> and is activated with a mouse middle-click. Text displayed anywhere on the screen can be edited, and if formatted with the required command syntax, can be middle-clicked and executed. Any text file containing suitably-formatted commands can be used as a so-called '''tool text''', thus serving as a user-configurable menu. Even the output of a previous command can be edited and used as a new command. This approach is radically different from both conventional dialogue-oriented console menus or [[command-line interface]]s but bears some similarities to the worksheet interface of the [[Macintosh Programmer's Workshop]].{{cn|date=April 2025}}

Since it does not use graphical [[Graphical widget|widgets]], only plain text, but offers comparable functionality to a [[GUI]] with a [[tiling window manager]], it is referred to as a Text User Interface or TUI. For a short introduction, see the 2nd paragraph on page four of the first published ''Report on the Oberon System''.<ref>{{cite tech report |author1-link=Niklaus Wirth |first1=Niklaus |last1=Wirth |first2=Jürg |last2=Gutknecht |date=1988 |title=The Oberon System |url=http://e-collection.library.ethz.ch/eserv/eth:3180/eth-3180-01.pdf |volume=88 |series=ETH Eidgenössische Technische Hochschule Zürich, Institut für Informatik |doi=10.3929/ethz-a-000487176 }}</ref>

Oberon's [[User Interface|UI]] influenced the design of the [[Acme (text editor)|Acme text editor and email client]] for the [[Plan 9 from Bell Labs]] operating system.

== In embedded systems ==
[[File:MicroVGA TUI demoapp.jpg|thumb|Embedded system displaying menu on an LCD screen]]

Modern [[embedded system]]s are capable of displaying TUI on a monitor like personal computers. This functionality is usually implemented using specialized integrated circuits, modules, or using [[FPGA]].

Video circuits or modules are usually controlled using [[VT100]]-compatible command set over [[UART]],{{Citation needed|date=January 2009}} FPGA designs usually allow direct video memory access.{{Citation needed|date=January 2009}}

== Other uses ==
* The [[full screen editor]] of the [[Commodore 64]] 8-bit computers was advanced in its market segment for its time. Users could move the cursor over the entire screen area, entering and editing [[BASIC]] program lines, as well as [[direct mode]] commands. All Commodore [[8-bit]] computers used the [[PETSCII]] character set, which included character glyphs suitable for making a TUI.
* Apple's [[Macintosh Programmer's Workshop]] programming environment included Commando, a TUI shell. It was the inspiration for BBEdit's shell worksheet.
* Later [[Apple II]] models included [[MouseText]], a set of graphical glyphs used for making a TUI.
* The [[Corvus Concept]] computer of 1982 used a [[function key]]-based text interface on a full-page pivoting display.

== See also ==
* [[Command-line interface]] (CLI)
* [[Console application]]
* [[Natural-language user interface]]
* [[Text-based game]], a game using a TUI
* [[VGA text mode]]
* [[IBM Monochrome Display Adapter|MDA]]

=== Examples of programming libraries ===
* [[curses (programming library)]]
* [[ncurses]]
* [[CDK (programming library)|CDK]]
* [[Newt (programming library)|Newt]], a widget-based toolkit
* [[S-Lang]]
* [[Turbo Vision]]
* [[Visual Basic (classic)|Early versions of Visual Basic]]

== References ==
{{Reflist}}

{{User interfaces}}
{{Operating system}}

[[Category:Text user interface| ]]
[[Category:User interfaces]]