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Acarriage return, sometimes known as acartridge return and often shortened toCR,<CR> orreturn, is acontrol character or mechanism used to reset a device's position to the beginning of aline of text. It is closely associated with the line feed andnewline concepts, although it can be considered separately in its own right.
Originally, the term "carriage return" referred to a mechanism or lever on atypewriter. For machines where the type element was fixed and the paper held in a movingcarriage, this lever was on the left attached to the moving carriage, and operated after typing a line of text to cause the carriage to return to the far right so the type element would be aligned to the left side of the paper. The lever would also usuallyfeed the paper to advance to the next line.
Many electric typewriters such asIBM Electric orUnderwood Electric made carriage return to be another key on the keyboard instead of a lever. The key was usually labeled "carriage return", "return", or "power return". With typewriters like theSelectric, where the type element moved when typing and the paper was held stationary, the key returned the type element to the far left and the term "carrier return" was sometimes used for this function.
To improve the keyboard for non-English-speakers, the symbol ↵ (U+21B5,HTML entity↵) was introduced to communicate the combined carriage return and line feed action.
Incomputing, the carriage return is one of thecontrol characters inASCII code,Unicode,EBCDIC, and many other codes. It commands aprinter, or other output system such as the display of asystem console, to move the position of thecursor to the first position on the same line. It was mostly used along withline feed (LF), a move to the next line, so that together they start a new line. Together, this sequence can be referred to asCRLF.[1]
The carriage return and line feed functions were split for practical reasons:
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 (seenewline); others use it only for aparagraph break (a "hard return"). Some standards which introduce their own representations for line and paragraph control (for exampleHTML) and many programming languages treat carriage return and line feed aswhitespace.
In both ASCII and Unicode, the carriage return is assignedcode point 13 (or 0D inhexadecimal); it may also be seen as control+M or^M. In character and string constants in theC programming language and in many other languages (including representations ofregular expressions[2][3]) influenced by C,\r denotes this character.[4]