Cut, copy, and paste
From Wikipedia, the free encyclopedia
In human-computer interaction, cut and paste and copy and paste offer user-interface paradigms for transferring text, data, files or objects from a source to a destination. Most ubiquitously, users require the ability to cut and paste sections of plain text. This paradigm has close associations with graphical user interfaces that use pointing devices such as a computer mouse (by drag and drop, for example).
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[edit] History
The term "cut and paste" derives from the traditional practice in manuscript-editing whereby people would literally cut paragraphs from a page with scissors and physically paste them onto another page. This practice remained standard as late as the 1960s. Stationery stores formerly sold "editing scissors" with blades long enough to cut an 8-1/2"-wide page. The advent of photocopiers made the practice easier and more flexible.
Lawrence G. Tesler (Larry Tesler) first transferred "cut and paste" into the context of computer-based text-editing while working at Xerox Corporation Palo Alto Research Center (PARC) in 1974-1975.[1]
Apple Computer widely popularized the computer-based cut-and-paste paradigm through the Lisa (1981) and Macintosh (1984) operating systems and applications. Apple mapped the functionalities to key-combinations consisting of a special modifier key held down while typing the letters X (for cut), C (for copy), and V (for paste), choosing a handful of keyboard sequences to control basic editing operations. The keys involved all cluster together at the left end of the bottom row of the standard QWERTY keyboard, and each key is combined with a control or special modifier key to perform the desired operation:
Microsoft later adopted similar key-combinations with the introduction of Windows. Common User Access (in Windows and OS/2) also uses combinations of the Insert, Del, Shift and Control keys.
Similar patterns of key combinations, later borrowed by others, remain widely available today in most GUI text editors, word processors, and file system browsers.
[edit] Cut and paste
Computer-based editing can involve very frequent use of cut-and-paste operations. Most software-suppliers provide several methods for performing such tasks, and this can involve (for example) key-combinations, pulldown menus, pop-up menus, and/or toolbar buttons.
- The user selects the text or file for moving by some method, typically by dragging over the text or file name with the pointing-device or holding down the Shift key while using the arrow keys to move the text cursor
- The user performs a "cut" operation via key combination, menu, or other means
- Visibly, "cut" text immediately disappears from its location.
- Conceptually, the text has now moved to a location often called the clipboard. The clipboard typically remains invisible. On most systems only one clipboard location exists, hence another cut or copy operation overwrites the previously stored information. Many UNIX text-editors provide multiple clipboard entries, as do some Windows clipboard-manager programs such as Microsoft Office.
- The user selects a location for insertion by some method, typically by clicking at the desired insertion point
- A paste operation takes place which visibly inserts the clipboard text at the insertion point. (The paste operation does not typically destroy the clipboard text: it remains available in the clipboard and the user can insert additional copies at other points)
Whereas cut-and-paste often takes place with a mouse-equivalent in Windows-like GUI environments, it may also occur entirely from the keyboard, especially in UNIX text editors, such as Pico or vi. The most common kind of cutting and pasting without a mouse involves the entire current line, but it may also involve text after the cursor until the end of the line and other more sophisticated operations.
When a software environment provides cut and paste functionality, a nondestructive operation called copy usually accompanies them; copy places a copy of the selected text in the clipboard without removing it from its original location.
The clipboard usually stays invisible, because the operations of cutting and pasting, while actually independent, usually take place in quick succession, and the user (usually) needs no assistance in understanding the operation or maintaining mental context.
[edit] Copy and paste
Copy-and-paste refers to the popular, simple method of reproducing text or other data from a source to a destination. It differs from cut and paste in that the original source text or data does not get deleted or removed. The popularity of this method stems from its simplicity and the ease with which users can move data between various applications visually — without resorting to permanent storage.
Copying often takes place in graphical user interface systems through use of the key-combinations Ctrl+C (used for killing the running process in UNIX terminals); or by using some other method, such as a context menu or a toolbar button. Once one has copied data into the area of memory referred to as the clipboard, one may paste the contents of the clipboard into a destination using the key combinations Ctrl+V, or other methods dependent on the system. Macintosh computers use the key combinations ⌘C and ⌘V.
The X Window System maintains an additional clipboard containing the most recently selected text; middle-clicking pastes the content of this "selection" clipboard into whatever the mouse pointer is on at that time.
Most terminal emulators and some other applications support the key combinations Ctrl-Insert to copy and Shift-Insert to paste. This is in accordance with the IBM Common User Access (CUA) standard.
[edit] Common implementations
[edit] Cut
- control-X
- control-W (Emacs)
- d (vi)
[edit] Copy
- control-C
- command-C (Apple)
- highlight (X Window system PRIMARY selection)
- control-Insert (Common User Access)
- y (vi)
[edit] Paste
- control-V (generic)
- middle-click (X Window system PRIMARY selection)
- right-click (DOS environments, for example)
- shift+Insert (Common User Access)
- command-V (Apple)
- control-Y (Emacs)
- p (vi)
[edit] Additional differences between moving and copying
In a spreadsheet, moving (cut and paste) need not equate to copying (copy and paste) and then deleting the original: when moving, references to the moved cells may move accordingly.
[edit] Comparison to verb-object paradigm
As of 2007, the cut-and-paste paradigm has become so universal that most computer-users may take it for granted. As an instructive comparison, there follows an example of a competing paradigm, popular in some early, highly-successful applications known for ease-of-use by the standards of their day:
- Initially, the user has not selected any text
- The user initiates the operation by selecting a move command in some manner
- The system displays a prompt such as "Move what?"
- The system enters a modal state in which the user can either select text or cancel the move-operation
- The user selects the text in some manner
- The system displays a prompt "To where?"
- The system enters a modal state in which the user can either indicate an insertion-point or cancel the move-operation
- The user indicates the insertion-point and confirms the move-operation
- The system displays the effects of the move
[edit] Multiple clipboards
Several GUI editors allow copying text into or pasting text from specific clipboards, typically using a special keystroke-sequence to specify a particular clipboard-number.
Similarly, a kill ring provides a LIFO stack used for cut-and-paste operations as an advanced type of clipboard capable of storing multiple pieces of data.[2] For example, the Emacs text-editor developed by Richard Stallman provides a kill ring.[3] Each time a user performs a cut or copy operation, the system adds the affected text to the ring. The user can then access the contents of a specific (relatively numbered) buffer in the ring when performing a subsequent paste-operation. One can also give kill-buffers individual names, thus providing another form of multiple-clipboard functionality.
