Control+C is a common computer command. It is generated by pressing the key while holding down the key on most

computer keyboards A computer keyboard is a peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Replacing early punched cards and paper tape technology, i ...

. In

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inst ...

environments that use the

control key In computing, a Control key is a modifier key which, when pressed in conjunction with another key, performs a special operation (for example, ); similar to the Shift key, the Control key rarely performs any function when pressed by itself. ...

to control the active program, control+C is often used to

copy Copy may refer to: *Copying or the product of copying (including the plural "copies"); the duplication of information or an artifact **Cut, copy and paste, a method of reproducing text or other data in computing **File copying **Photocopying, a pr ...

highlighted text to the

clipboard A clipboard is a thin, rigid board with a clip at the top for holding paper in place. A clipboard is typically used to support paper with one hand while writing on it with the other, especially when other writing surfaces are not available. Th ...

. In many command-line interface environments, control+C is used to abort the current task and regain user control. It is a special sequence that causes the

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

to send a

signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...

to the active program. Usually the signal causes it to end, but the program may "catch" it and do something else, typically returning control to the user.

In graphical environments

Larry Tesler Lawrence Gordon Tesler (April 24, 1945 – February 16, 2020) was an American computer scientist who worked in the field of human–computer interaction. Tesler worked at Xerox PARC, Apple, Amazon, and Yahoo! While at PARC, Tesler's work include ...

created the concept of cut, copy, paste, and undo for human-computer interaction while working at

Xerox PARC PARC (Palo Alto Research Center; formerly Xerox PARC) is a research and development company in Palo Alto, California. Founded in 1969 by Jacob E. "Jack" Goldman, chief scientist of Xerox Corporation, the company was originally a division of Xero ...

to control text editing. During the development of the

Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and software en ...

it was decided that the cut, paste, copy and undo would be used frequently and assigned them to the ⌘-Z (Undo), ⌘-X (Cut), ⌘-C (Copy), and ⌘-V (Paste). The four letters are all located together at the left end of the bottom row of the standard

QWERTY QWERTY () is a keyboard layout for Latin-script alphabets. The name comes from the order of the first six keys on the top left letter row of the keyboard ( ). The QWERTY design is based on a layout created for the Sholes and Glidden t ...

keyboard. IBM and early versions of windows used a different set of keys as part of IBM Common User Access. Later versions of Windows adopted the shortcuts using Control instead of the Command key.

In command-line environments

Control+C was part of various

Digital Equipment Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

operating systems, including TOPS-10 and

TOPS-20 The TOPS-20 operating system by Digital Equipment Corporation (DEC) is a proprietary OS used on some of DEC's 36-bit mainframe computers. The Hardware Reference Manual was described as for "DECsystem-10/DECSYSTEM-20 Processor" (meaning the DEC PDP- ...

. Its popularity as an abort command was adopted by other systems including

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, an ...

. Later systems that copied it include CP/M,

DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...

and

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ser ...

. In

POSIX The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming inter ...

systems, the sequence causes the active program to receive

SIGINT Signals intelligence (SIGINT) is intelligence-gathering by interception of '' signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication ...

, the interruption signal. If the program does not specify how to handle this condition, the program is terminated. Typically a program that ''does'' handle a SIGINT will still terminate itself, or at least terminate the task running inside it. This system is usually preserved even in graphical

terminal emulator A terminal emulator, or terminal application, is a computer program that emulates a video terminal within some other display architecture. Though typically synonymous with a shell or text terminal, the term ''terminal'' covers all remote term ...

s. If control-C is used for copy in the graphical environment, an ambiguity arises. Typically an alternate keystroke is assigned to one of the commands, and both appear in the emulator's menus. As many keyboards and

computer terminal A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and ...

s once directly generated

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because ...

code, the choice of control+C overlapped with the

end-of-text character The End-of-Text character (ETX) is a control character used to inform the receiving computer that the end of a record has been reached. This may or may not be an indication that all of the data in a record have been received. In ASCII and in EB ...

. This character has a numerical value of three, as "''C''" is the third letter of the alphabet. It was chosen to cause an interrupt as it is otherwise unlikely to be part of a program's interactive interface.

References

{{Reflist Computer keys

In graphical environments

In command-line environments

See also

References