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For other uses, see Cursor.
A blinking text cursor.
In computing, a cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input from a text input or pointing device. The text cursor may be referred to as a caret in some cases[1][2]. This term came about from older unix systems that used the caret symbol as a text insertion indicator[citation needed]. The mouse cursor may be referred to as a mouse pointer [3], owing to its arrow shape on some systems.
[edit] Text cursor
The cursor for a typical Unix shell command prompt
In most command line interfaces or text editors, the cursor is an underscore, a solid rectangle, or a vertical line, which may be flashing or steady, indicating where text will be placed when entered (the insertion point). In the old days of text mode displays, it was not possible to show a vertical bar between characters to show where the new text would be inserted, so an underscore or block cursor was used instead. On text editors and word processors of modern design on bitmapped displays, the vertical bar is typically used instead. Some older graphical user interfaces such as OPEN LOOK used a caret-shaped insertion marker. Still today, the text cursor is sometimes called caret. 
The cursor for the Windows Command Prompt
A typical text insertion point
Some interfaces use an underscore or thin vertical bar to indicate that the user is in insert mode, where text will be inserted in the middle of the existing text, and a larger block to indicate that the user is in overtype mode, where inserted text will overwrite existing text. In this way, a block cursor may be seen as a piece of selected text one character wide, since typing will replace the text "in" the cursor with the new text. [edit] Bidirectional textA vertical line text cursor with a small left-pointing or right-pointing appendage are for indicating the direction of text flow on systems that support Bi-directional text, and is thus usually known among programmers as a 'bidi cursor'. In some cases, the cursor may split into two parts, each indicating where left-to-right and right-to-left text would be inserted.[4] [edit] Mouse cursorInterfaces driven by a computer mouse or other pointing device add a second cursor to show the current position of the mouse pointer. Douglas Engelbart's On-Line System originally referred to the cursor as a "bug" or "tracking spot" [5]. In the On-Line System, the cursor appearance alternated "between the characters uparrow and plus" [5]. On modern systems the default mouse cursor is an arrow pointing up and to the left, and is called the "mouse pointer". In text user interfaces, including the Linux console and many MS-DOS programs, this cursor is frequently a solid rectangle; depending on the interface, the rectangle may always be a single color, or may be the opposite color of whatever lies "below" it. Graphical user interfaces usually use an arrow-like pointer to show the mouse position, and a solid line as a text insertion point. The blinking of the text cursor is usually temporarily suspended when it is being moved; otherwise, the cursor may change position when it is not visible, making its location difficult to follow. Many TUIs and GUIs give the user the option to turn off the mouse cursor when text is being typed. In many GUIs, the mouse cursor changes shape depending on the circumstances. For example:
The mouse cursor hotspot is the mouse cursor's pixel used to click. A hotspot is normally on the cursor's top corner, though it may reside at any location in the cursor icon.[6][7] [edit] See also
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[edit] External links
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