View source for Esc key

{{Short description|Computer key}}
{{other uses|ESC (disambiguation){{!}}ESC}}
{{Not to be confused with|Escape character}}
[[File:German-T2-Keyboard-Prototype-May-2012.jpg|thumb|upright=1.2|A computer keyboard with the Esc key in the top-left corner]]
[[File:IBM 5150 Keyboard.jpg|thumb|IBM 83-key keyboard (1981), with Esc in the top-left corner of the alphanumeric section]]

On [[Keyboard (computing)|computer keyboard]]s, the '''Esc key''' {{keypress|Esc}} (named ''Escape key'' in the international standard series [[ISO/IEC 9995]]) is a key used to generate the [[escape character]] (which can be represented as [[ASCII]] code 27 in decimal, [[Unicode]] U+001B, or {{keypress|Ctrl|[}}). The escape character, when sent from the keyboard to a computer, often is interpreted by software as "stop", "cancel" or "exit", and when sent from the computer to an external device (including many printers since the 1980s, [[computer terminal]]s and [[Linux console]]s, for example) marks the beginning of an [[escape sequence]] to specify operating modes or characteristics generally.

It is now generally placed at the top left corner of the keyboard, a convention dating at least to the original [[IBM PC keyboard]], though the key itself originated decades earlier with [[teletypewriter]]s.

== Symbol ==
[[File:ISO 7000 - Ref-No 2029.svg|thumb|upright=0.6|ISO keyboard symbol for "Escape"]]

The keyboard symbol for the ESC key (which may be used when the usual Latin lettering is not preferred for labelling the key) is standardized in [[ISO/IEC 9995]]-7 as symbol 29, and in ISO 7000 ''"Graphical symbols for use on equipment"'' as symbol ISO-7000-2029. This symbol is encoded in [[Unicode]] as U+238B {{smallcaps|broken circle with northwest arrow}} (⎋).

== Origins ==
The name of the equivalent key on some early [[Teletype Model 33]] keyboards was labeled '''Alt Mode'''..., the alternative mode of operation causing the escapement to treat the following one character in a special way. Much later printers and [[computer terminals]] that would use [[escape sequences]] often would take more than one following byte as part of a special sequence.

== Uses ==

As most modern computer users are no longer concerned with controlling [[computer terminal|terminal]] or [[peripheral]] behaviour via manually typed or computer-issued escape sequences, the task to which {{keypress|Esc}} was originally dedicated, the escape key has long since been appropriated by [[application software|application]] programmers, most often to mean ''Stop''.  This use continues today in [[Microsoft Windows]]'s method of escape as a shortcut in dialog boxes for ''No'', ''Quit'', ''Exit'', ''Cancel'', or ''Abort'', as well as a common shortcut key for the ''Stop'' button in many [[web browsers]], and to cancel [[drag and drop]] operations.<ref>{{cite web |url=http://www.cs.virginia.edu/faq/netscape/Netscape.keybindings.html |title=Netscape for UNIX keybindings |access-date=2009-02-07 |url-status=dead |archive-url=https://web.archive.org/web/20060919035551/http://www.cs.virginia.edu/faq/netscape/Netscape.keybindings.html |archive-date=2006-09-19 }}</ref><ref>{{cite web |url=http://blogs.msdn.com/ie/attachment/715071.ashx |title=Internet Explorer 7 Quick Reference Guide |access-date=2009-02-07 |url-status=dead |archive-url=https://web.archive.org/web/20090218115952/http://blogs.msdn.com/ie/attachment/715071.ashx |archive-date=2009-02-18 }}</ref><ref>{{cite web|url=https://www.scribd.com/doc/9635540/Cheat-Sheet-for-Mozilla-FireFox-Key-Board-Short-Cuts|title=Cheat Sheet for Mozilla FireFox (Key Board Short Cuts)|work=scribd.com|access-date=4 December 2016}}</ref>

On machines running [[Microsoft Windows]], prior to the implementation of the [[Windows key]] on keyboards, the typical practice for invoking the "start" button was to hold down the [[Control key]] and press escape. This key combination still works as of Windows 11.<ref>{{cite web|title=Ctrl+Esc, U, Enter: Shutdown Windows (XP and earlier)|url=http://www.zeigen.com/shortcuts/2007/02/23/shutdown/|access-date=26 April 2012|archive-date=18 July 2017|archive-url=https://web.archive.org/web/20170718133604/http://www.zeigen.com/shortcuts/2007/02/23/shutdown/|url-status=dead}}</ref>

Microsoft Windows makes use of "Esc" for many key shortcuts.<ref>{{Cite web|url=https://support.microsoft.com/en-us/windows/keyboard-shortcuts-in-windows-dcc61a57-8ff0-cffe-9796-cb9706c75eec|title=Keyboard shortcuts in Windows|website=support.microsoft.com}}</ref>  Many of these shortcuts have been present since [[Windows 3.0]], through [[Windows XP]] and later.

In macOS, "Esc" usually closes or cancels a dialog box or sheet. The {{key top|Command}}+{{Key top|Option}}+{{key top|Esc}} combination opens the [[Force Quit]] dialog box, allowing users to end non-responsive applications. Another use for the Esc key, in combination with the Command key, is switching to [[Front Row (software)|Front Row]], if installed.

In most computer games, the escape key is used as a pause button and/or as a way to bring up the in-game menu, usually containing ways to exit the program. This is despite the existence of a separate [[Pause key|Pause/Break key]].

[[File:KB Terminal ADM3A.svg|thumb|450px|[[ADM-3A]] keyboard layout used in vi development, with escape in what is now the {{key top|Tab}} position]]

In the [[Vi (text editor)|vi]] family of text editors, escape is used to switch modes. This usage is a legacy of the {{keypress|Esc}} key being conveniently placed in the [[Top row (keyboard)|top row]] on the [[ADM-3A]] terminal keyboard used to develop vi, in what on modern keyboards is now the tab position – yet on modern keyboards, Esc is now inconveniently located, most often in the [[function key]]s row. This is similar to how the extensive modifier keys in [[Emacs]] were easily used on the original keyboard (the [[space-cadet keyboard]])—being placed together—but these keys have now been spread around the keyboard, and hence become more difficult to use.

The [[TECO (text editor)|TECO]] editor uses ESCape as a delimiter when used once, and as an ''execute'' key when used twice in a row.<ref>{{cite web
   |url=https://sdf.org/?tutorials/survival-teco-2.0
   |title=Survival TECO}}</ref>

===Escape sequences on KSR terminals===
Old keyboard Send/Receive (KSR) printers, and [[Computer terminals|visual display units]] (VDUs), would normally be controlled by [[escape sequences]] sent by the computer to the peripheral device, but there were situations where these devices could be used "off-line" with the keyboard effectively connected to the output device, and so the need could arise to type escape sequences "by hand" to control the peripheral. Although such devices are long out of use, standard processing<ref>"[http://www.joelonsoftware.com/articles/Unicode.html About Unicode and Character Sets]", Joel Spolsky, ''Joel on Software''</ref> of [[ANSI escape codes|ANSI Escape sequences]] very similar to the 1970s [[VT100]], is implemented in both [[ANSI.SYS]] and other more modern pseudo-terminal interfaces used in [[Unix-like]] environments, one example being [[Linux console]]s, meaning newer, higher-level abstractions haven't changed the fact that typing the escape key followed by something like the six characters ''[32;1m'' affects subsequently text in output, in this case turning it green.

== References ==
{{reflist}}

{{Keyboard}}
{{keyboard keys}}

[[Category:Computer keys]]