Backspace

Backspace (BS) is ASCII code 8, one of the 33 control characters. On early teletypes, BS physically moved the print head one position left without erasing, which allowed overstrike effects - typing "a", then BS, then "^" would produce "a" with a circumflex.

Modern terminals interpret BS differently: most erase the previous character and shift remaining text left. In programming, the escape sequence \b represents BS in C, Python, and JavaScript, but its behavior varies by output target - it erases in a terminal but does nothing in a log file. The related DEL character (code 127) was designed for paper tape correction, where punching all 7 holes "deleted" a character.