In computing, a Control keyCtrl is a modifier key which, when pressed in conjunction with another key, performs a special operation (for example, Ctrl+C); similar to the Shift key, the Control key rarely performs any function when pressed by itself. The Control key is located on or near the bottom left side of most keyboards (in accordance with the international standard ISO/IEC 9995-2), with many featuring an additional one at the bottom right.
A Control key (marked "Ctrl") on a Windows keyboard next to one style of a Windows key, followed in turn by an Alt key
On keyboards that use English abbreviations for key labeling, it is usually labeled Ctrl (rarely, Control or Ctl is seen). Abbreviations in the language of the keyboard layout also are in use, e.g., the German keyboard layout uses Strg as required by the German standard DIN 2137:2012-06. Also, there is a standardized keyboard symbol (to be used when Latin lettering is not preferred), given in ISO/IEC 9995-7 as symbol 26, and in ISO 7000 "Graphical symbols for use on equipment" as symbol ISO-7000-2028. This symbol is encoded in Unicode as U+2388 helm symbol (⎈).
On teletypewriters and early keyboards, holding down the Control key while pressing another key zeroed the leftmost two bits of the seven bits in the generated ASCII character. This allowed the operator to produce the first 32 characters in the ASCII table. These are non-printing characters that signal the computer to control where the next character will be placed on the display device, eject a printed page or erase the screen, ring the terminal bell, or some other operation. For example, the character or "G", whose ASCII code is 71 in base 10, or 100 0111 in binary, would be transformed into the binary code 000 0111 (7 in decimal), which is assigned to the bell character. Aptly, these characters are also called control characters.
Using the Ctrl key with either lowercase letters (e.g. C, ASCII code 100 0011) or uppercase letters (⇧ Shift+C, ASCII 110 0011) will generate the same ASCII code on a teletypewriter, because holding down the control key grounds (zeros the voltage on) the two wires used to carry the leftmost two bits from the keyboard, ignoring their modification by the ⇧ Shift key. In modern computers, the interpretation of keypresses is generally left to the software. Modern keyboards distinguish each physical key from every other and report all keypresses and releases to the controlling software.
When the original purpose of the ASCII control characters became either obsolete or seldom used, later software appropriated the Control key combinations for other purposes.
The keyboards of many early computer terminals, including the Teletype Model 33 ASR and Lear-SieglerADM-3A, and early models of the IBM PC, positioned the Control key on the left of the keyboard, whereas caps lock resides in the same position on most modern keyboards. The traditional layout was preserved for later workstation systems and is often associated with Unix workstations. Keyboards from Sun Microsystems came in two layouts; "Unix" and "PC-style", with the Unix layout having the traditional placing of the Control key and other keys.[1] The keyboards produced for One Laptop Per Child computers also have the Control key in this location.[2] Other vendors produce keyboards for different computer systems with this placement of the Control key, such as the Happy Hacking Keyboard.
Some users of keyboards with caps lock on the left remap the keys to exchange Control and caps lock, finding the traditional location more ergonomic for using programs benefiting from use of the Control key. Keyboard layout preferences specifically to address this need are available in some operating systems.
Others leave the control key in the lower-left corner of the keyboard, and press it using the side of their palm. The choice of location for the control key often comes down to the typist's hand shape and posture.
Notation
There are several common notations for pressing the Control key in conjunction with another key. Each notation below means press and hold Ctrl while pressing the X key:
In early first-person shooters, the left Ctrl key is often used to fire a weapon. In newer games, the key is often used for crouching instead.[5]
Similar concepts
Generally, the Command key, labeled with the ⌘ symbol on Apple Macintosh computers, performs the equivalent functions in classic Mac OS and macOS applications (for example, ⌘C copies, while ⌘P prints; the same holds for saving, cutting, and pasting).
Macintoshes also have a Control key, but it has different functionality. The original Apple mouse design reduced complexity by only offering one button. As the interface developed, contextual menus were offered to access extra options. Another button was needed to access these. On Unix and Windows, the user had other mouse buttons to use. On Classic Mac OS and macOS, the Control key is used to invoke a "right-click". Apple calls this a "secondary click" as left-handers can choose which side this button is on.
It is mostly used as a modifier key for key-combinations.
Pressing Control and clicking the mouse button will invoke a contextual menu. This is a compatibility feature for users with one-button mice; users with two-button mice just use the right mouse-button, with no modifiers.
In Quickbooks, the Control Key is used to validate login credentials during OLSU 1016 and OLSU 1013 errors. Keeping it depressed while sending information to the Quickbooks servers fixes the errors.
Under macOS, the Control key allows the use of Emacs-style key combinations in most text entry fields. For example, Ctrl-A moves the caret to the start of the paragraph, Ctrl-L vertically centers the current line in the editing field, Ctrl-K cuts text to the end of the line to a kill ring separate from the normal clipboard, etc.
References
^Complex Text Layout Language Support in the Solaris Operating Environment docs.oracle.com/cd/E19455-01/806-5583/806-5583.pdf
^Don Marti (2006-10-27). "Doing it for the kids, man: Children's laptop inspires open source projects". Linux World. Retrieved 2010-06-11.
^"OS X Yosemite: What are those symbols shown in menus?". Apple Support. Apple Inc. Sep 23, 2015.
^"Mac keyboard shortcuts". Apple Support. Apple Inc. December 7, 2015. Retrieved December 28, 2015.
^Lahti, Evan (August 5, 2016). "Anyone who uses the C key to crouch is a hopeless degenerate". PC Gamer.
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Ctrl redirects here For other uses see CTRL In computing a Control key Ctrl is a modifier key which when pressed in conjunction with another key performs a special operation for example Ctrl C similar to the Shift key the Control key rarely performs any function when pressed by itself The Control key is located on or near the bottom left side of most keyboards in accordance with the international standard ISO IEC 9995 2 with many featuring an additional one at the bottom right A Control key marked Ctrl on a Windows keyboard next to one style of a Windows key followed in turn by an Alt key ISO keyboard symbol for Control On keyboards that use English abbreviations for key labeling it is usually labeled Ctrl rarely Control or Ctl is seen Abbreviations in the language of the keyboard layout also are in use e g the German keyboard layout uses Strg as required by the German standard DIN 2137 2012 06 Also there is a standardized keyboard symbol to be used when Latin lettering is not preferred given in ISO IEC 9995 7 as symbol 26 and in ISO 7000 Graphical symbols for use on equipment as symbol ISO 7000 2028 This symbol is encoded in Unicode as U 2388 helm symbol Contents 1 History 2 Location 3 Notation 4 Table of examples 5 Similar concepts 6 References 7 See alsoHistory EditSee also Control character How control characters map to keyboards On teletypewriters and early keyboards holding down the Control key while pressing another key zeroed the leftmost two bits of the seven bits in the generated ASCII character This allowed the operator to produce the first 32 characters in the ASCII table These are non printing characters that signal the computer to control where the next character will be placed on the display device eject a printed page or erase the screen ring the terminal bell or some other operation For example the character or G whose ASCII code is 71 in base 10 or 100 0111 in binary would be transformed into the binary code 000 0111 7 in decimal which is assigned to the bell character Aptly these characters are also called control characters Using the Ctrl key with either lowercase letters e g C ASCII code 100 0011 or uppercase letters Shift C ASCII 110 0011 will generate the same ASCII code on a teletypewriter because holding down the control key grounds zeros the voltage on the two wires used to carry the leftmost two bits from the keyboard ignoring their modification by the Shift key In modern computers the interpretation of keypresses is generally left to the software Modern keyboards distinguish each physical key from every other and report all keypresses and releases to the controlling software When the original purpose of the ASCII control characters became either obsolete or seldom used later software appropriated the Control key combinations for other purposes Location EditFurther information Caps lock Placement The keyboards of many early computer terminals including the Teletype Model 33 ASR and Lear Siegler ADM 3A and early models of the IBM PC positioned the Control key on the left of the keyboard whereas caps lock resides in the same position on most modern keyboards The traditional layout was preserved for later workstation systems and is often associated with Unix workstations Keyboards from Sun Microsystems came in two layouts Unix and PC style with the Unix layout having the traditional placing of the Control key and other keys 1 The keyboards produced for One Laptop Per Child computers also have the Control key in this location 2 Other vendors produce keyboards for different computer systems with this placement of the Control key such as the Happy Hacking Keyboard Some users of keyboards with caps lock on the left remap the keys to exchange Control and caps lock finding the traditional location more ergonomic for using programs benefiting from use of the Control key Keyboard layout preferences specifically to address this need are available in some operating systems Others leave the control key in the lower left corner of the keyboard and press it using the side of their palm The choice of location for the control key often comes down to the typist s hand shape and posture Notation EditThere are several common notations for pressing the Control key in conjunction with another key Each notation below means press and hold Ctrl while pressing the X key X Traditional caret notationC x Emacs and Vim notationCTRL X Old Microsoft notationCtrl X Current Microsoft notationCtrl X OpenVMS notation X Classic Mac OS and macOS notation used in menus and Sticky Keys similar to caret notation but using U 2303 UP ARROWHEAD instead of a caret 3 Control X Classic Mac OS and macOS notation used in prose 4 CNTL X Cisco IOS notation X Bar notationTable of examples EditDifferent application programs user interfaces and operating systems use the various control key combinations for different purposes Key combination Microsoft Windows KDE GNOME Unix command line and programs using readline Emacs if different from Unix command line Ctrl A Select all Beginning of lineCtrl B Bold Backward one characterCtrl C Copy Generate SIGINT terminate program Compound commandCtrl D Font window word processing Add to bookmarks Browsers Forward delete or if line is empty end of input traditional Unix Forward deleteCtrl E Center alignment word processing End of lineCtrl F Find usually a small piece of text in a larger document Forward one characterCtrl G Go to line number Abort current operationCtrl H Replace History Delete previous character Help keyCtrl I Italic Incremental search Command line completion same as Tab key Ctrl J Justify Line feed LFD LFD to evaluate Lisp expressions Ctrl K Insert hyperlink word processing Cut Kill text between cursor and end of lineCtrl L Create list Left align word processing Clear screen Redraw window terminal and recenter view around current lineCtrl M Increase margin by 1 2 inch word processing Same as Enter keyCtrl N New window document etc Next line in history Next lineCtrl O Open Enter plus next line in history Insert open new lineCtrl P Print Previous line in history Previous lineCtrl Q Quit application Resume transmission Literal insertCtrl R Refresh page Right align word processing Search backwards in history Search backwardsCtrl S Save Pause transmission Search forwardCtrl T Open new tab Transpose characters display statusCtrl U Underline Cut text between beginning of line and cursor Prefix numerical argument to next commandCtrl V Paste Literal insert Page downCtrl W Close window or tab Cut previous word CutCtrl X Cut Compound commandCtrl Y Redo PasteCtrl Z Undo Suspend program Iconify windowCtrl Shift Z Redo not availableCtrl Decrease font size Same as Esc or AltCtrl Increase font size Search for the next character typed undefined or rarely usedCtrl Toggle font subscript not availableCtrl Shift Toggle font superscript not availableCtrl End Bottom end of document or window undefined or rarely used Bottom end of text buffer Ctrl Home Top start of document or window undefined or rarely used Top start of text buffer Ctrl Insert Copy undefined or rarely used CopyCtrl PgDn Next tab undefined or rarely used Scroll window to the rightCtrl PgUp Previous tab undefined or rarely used Scroll window to the leftCtrl Tab Next window or tab not availableCtrl Shift Tab Previous window or tab not availableCtrl Grow Screen not availableCtrl Shrink Screen UndoCtrl undefined or rarely used Same as Ctrl Undo Ctrl undefined or rarely used Generate SIGQUIT terminate and dump core undefined or rarely usedCtrl Previous word undefined or rarely used Previous wordCtrl Next word undefined or rarely used Next wordCtrl Delete Delete next word undefined or rarely used Delete next wordCtrl Backspace Delete previous word undefined or rarely used Delete previous wordCtrl Alt Backspace undefined or rarely used on Windows restart X11 on Unix like desktops undefined or rarely usedCtrl Alt Rotate screen right side up undefined or rarely usedCtrl Alt Rotate screen upside down undefined or rarely usedCtrl Alt Rotate screen left undefined or rarely usedCtrl Alt Rotate screen right undefined or rarely usedCtrl Shift Esc Open task manager not availableCtrl Alt Del Reboot Open task manager or session options not availableCtrl Mousewheel Scroll in outIn early first person shooters the left Ctrl key is often used to fire a weapon In newer games the key is often used for crouching instead 5 Similar concepts EditGenerally the Command key labeled with the symbol on Apple Macintosh computers performs the equivalent functions in classic Mac OS and macOS applications for example C copies while P prints the same holds for saving cutting and pasting Macintoshes also have a Control key but it has different functionality The original Apple mouse design reduced complexity by only offering one button As the interface developed contextual menus were offered to access extra options Another button was needed to access these On Unix and Windows the user had other mouse buttons to use On Classic Mac OS and macOS the Control key is used to invoke a right click Apple calls this a secondary click as left handers can choose which side this button is on It is mostly used as a modifier key for key combinations Pressing Control and clicking the mouse button will invoke a contextual menu This is a compatibility feature for users with one button mice users with two button mice just use the right mouse button with no modifiers It is used in the command line interface with programs made for that interface In Quickbooks the Control Key is used to validate login credentials during OLSU 1016 and OLSU 1013 errors Keeping it depressed while sending information to the Quickbooks servers fixes the errors Under macOS the Control key allows the use of Emacs style key combinations in most text entry fields For example Ctrl A moves the caret to the start of the paragraph Ctrl L vertically centers the current line in the editing field Ctrl K cuts text to the end of the line to a kill ring separate from the normal clipboard etc References Edit Complex Text Layout Language Support in the Solaris Operating Environment docs oracle com cd E19455 01 806 5583 806 5583 pdf Don Marti 2006 10 27 Doing it for the kids man Children s laptop inspires open source projects Linux World Retrieved 2010 06 11 OS X Yosemite What are those symbols shown in menus Apple Support Apple Inc Sep 23 2015 Mac keyboard shortcuts Apple Support Apple Inc December 7 2015 Retrieved December 28 2015 Lahti Evan August 5 2016 Anyone who uses the C key to crouch is a hopeless degenerate PC Gamer See also EditAlt key Break key Control characters Control Alt Delete Function key Keyboard layout Modifier key IBM Common User AccessIBM PC keyboard Windows ANSI US layout vteEsc F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 PrtScn SysRq ScrollLock Pause Break Insert Home PgUp NumLock Delete End PgDn 7 8 9 4 5 6 1 2 3 Enter 0 Ins Del Retrieved from https en wikipedia org w index php title Control key amp oldid 1134753507, wikipedia, wiki, book, books, library,
