Backspace (← Backspace,⌫) is the keyboard key that intypewriters originally pushed the carriage one position backwards, and in modern computer systems typically moves thedisplay cursor one position backwards,[note 1] deletes the character at that position, and shifts back any text after[note 2] that position by one character.
Although the term "backspace" is the traditional name of the key which steps the carriage back and/or[note 3] deletes the previous character, typically to the left of the cursor, the actual key may be labeled in a variety of ways, for exampledelete,[1]erase,[note 4] or with a left pointing arrow.[3] A dedicated symbol for "backspace" exists asU+232B ⌫ but its use as a keyboard label is not universal. Some very early typewriters labeled this key thebackspacer key.
Backspace is distinct from thedelete key, which in ateletypewriter would punch out all the holes inpunched paper tape to strike out a character, and in modern computers deletes text at orfollowing the cursor position. Also, the delete key often works as a generic command to remove an object (such as an image inside a document, or a file in afile manager), while backspace usually does not.[4][5] Full-sizeMac keyboards have two keys labeleddelete; a key that functions as a backspace key, and a key that functions as a delete key. Smaller Mac keyboards, such as laptop keyboards, have only a key that functions as a backspace key.[6]
In some[note 5] typewriters, a typist would, for example, type a lowercase letter A with acute accent (á) by typing a lowercase letter A, backspace, and then the acute accent key. This technique (also known asoverstrike) is the basis for such spacing modifiers in computer character sets such as theASCII caret (^, for thecircumflex accent). Backspace composition no longer works with typical modern digital displays or typesetting systems.[note 6] It has to some degree been replaced with thecombining diacritical marks mechanism ofUnicode, though such characters do not work well with many fonts, and precomposed characters continue to be used. Some software likeTeX orMicrosoft Windows use the opposite method for diacritical marks, namely positioning the accent first, and then the base letter on its position.
In modern systems, the backspace key is often mapped to the delete character (0x7f in ASCII or Unicode), although the backspace key's function of deleting the character before the cursor remains.[3] In computers, backspace can also delete a precedingnewline character, something generally inapplicable to typewriters.
The backspace key is commonly used to go back a page or up one level in graphical web or file browsers.
Pressing the backspace key on acomputer terminal would generate theASCII code 08, BS or Backspace, acontrol code which would delete the preceding character. That control code could also be accessed by pressingControl+H, asH is the eighth letter of theLatin alphabet. Terminals which did not have the backspace code mapped to the function of moving the cursor backwards and deleting the preceding character would display the symbols^H (caret, H) when the backspace key was pressed. Even if a terminal did interpret backspace by deleting the preceding character, the system receiving the text might not. Then, the sender's screen would show a message without the supposedly deleted text, while that text, and the deletion codes, would be visible to the recipient. This sequence is still used humorously forepanorthosis by computer literates, denoting the deletion of a pretended blunder, much like astrikethrough; in this case, however, the ^H symbol is faked by typing a regular '^' followed by typing a regular 'H'.
Example:
An alternative sometimes seen is^W, which is the shortcut to delete the previous word in the Berkeley Unix terminalline discipline. This shortcut has also made it into the insert mode of theVi text editor and its cloneVim.[8]
^U deletes a line.[9]
| Esc | F1 | F2 | F3 | F4 | F5 | F6 | F7 | F8 | F9 | F10 | F11 | F12 | PrtScn/ SysRq | Scroll Lock | Pause/ Break | |||||||||
 | Insert | Home | PgUp | Num Lock | ∕ | ∗ | − | |||||||||||||||||
| Delete | End | PgDn | 7 | 8 | 9 | + | ||||||||||||||||||
| 4 | 5 | 6 | ||||||||||||||||||||||
| ↑ | 1 | 2 | 3 | Enter | ||||||||||||||||||||
| ← | ↓ | → | 0 Ins | . Del | ||||||||||||||||||||
