backspaces

Backspace refers to the backspace key on keyboards and to the corresponding control character in computing. It moves the cursor one position to the left and typically erases the character at that position, allowing a user to correct typos during text entry. In many systems the backspace operation is realized by sending the ASCII control code BS (hex 08) or the Unicode U+0008; when processed by a terminal or console, the device may move the cursor left and overwrite the previous character with a space, or it may delete the character from the input buffer without changing the display.

Historically, backspace originated with typewriters and early teletypes, where the operator would physically move the print head back to overstrike or erase. With the advent of computer terminals, the backspace code and the separate delete key (or DEL) emerged to support editing of text streams.

In software, the effect of backspace can vary. In command shells and terminal emulators, backspace typically removes the preceding character in the input line. In text editors and word processors, the key deletes the previous glyph or code unit, with some editors able to operate on grapheme clusters or on logical characters. In Unicode and multibyte encodings, backspace often acts on code units rather than user-perceived characters, leading to display issues with complex scripts.

The delete key (DEL) and the backspace key perform different actions in many environments. Some modern interfaces treat backspace as a conventional delete, while others distinguish between deleting characters, words, or whole fields, often using modifier keys (Ctrl, Alt).