In
computing, the carriage return is one of the
control characters in
ASCII code,
Unicode,
EBCDIC, and many other codes. It commands a
printer, or other output system such as the display of a
system console, to move the position of the
cursor to the first position on the same line. It was mostly used along with
line feed (LF), a move to the next line, so that together they start a new line. Together, this sequence can be referred to as
CRLF. The carriage return and line feed functions were split for practical reasons: • Carriage return by itself provided the ability to overprint the line with new text. This could be used to produce bold or accented characters, underscores, struck-out text, and some composite symbols. • Early mechanical printers were too slow to return the carriage in the time it took to process one character. Therefore, the time spent sending the line feed was not wasted (often several more characters had to be sent to ensure the carriage return had happened before sending a printing character). This is why the carriage return was always sent first. • It was then also possible to fit multiple line feed operations into the time taken for a single carriage return—for example for printing doublespaced text, headers/footers or title pages—to save print and transmission time without the need for additional circuitry or mechanical complexity to "filter out" spurious additional CR signals. As early as 1901,
Baudot code contained separate carriage return and line feed characters. Many computer programs use the carriage return character, alone or with a line feed, to signal the end of a line of text, but other characters are also used for this function (see
newline); others use it only for a
paragraph break (a "hard return"). Some standards which introduce their own representations for line and paragraph control (for example
HTML) and many programming languages treat carriage return and line feed as
whitespace. In both ASCII and Unicode, the carriage return is assigned
code point 13 (or 0D in
hexadecimal); it may also be seen as control+M or . In character and string constants in the
C programming language and in many other languages (including representations of
regular expressions) influenced by C, \r denotes this character. ==See also==