简而言之:

回车符(\r或0xD):从同一行开始控制。 换行(\n或0xA):控制从下一行开始。 表单提要(\f或0xC):控制从下一页开始。

更多的细节和更多的控制字符可以在下面的页面找到:控制字符

Consider an IBM 1403 impact printer. CR moved the print head to the start of the line, but did NOT advance the paper. This allowed for "overprinting", placing multiple lines of output on one line. Things like underlining were achieved this way, as was BOLD print. LF advanced the paper one line. If there was no CR, the next line would print as a staggered-step because LF didn't move the print head. FF advanced the paper to the next page. It typically also moved the print head to the start of the first line on the new page, but you might need CR for that. To be sure, most programmers coded CRFF instead of CRLF at the end of the last line on a page because an extra CR created by FF wouldn't matter.

作为补充，

1、回车:这是打印机术语，意思是将打印位置更改到当前行的开头。在计算机世界中，它在大多数情况下表示返回到当前行的开始，但很少表示新行。

2、换行:这是打印机术语，意思是把纸张往前行。因此换行和换行一起使用，在新行开始时开始打印。在计算机世界中，它通常与换行符具有相同的含义。

3、表单提要:这是一个打印机术语，我喜欢这个帖子中的解释。

如果您正在为一台20世纪80年代风格的打印机编程，它将弹出 纸，开始新的一页。你几乎可以肯定永远不需要 它。 http://en.wikipedia.org/wiki/Form_feed

它几乎已经过时了，你可以参考转义序列\f - form feed -它到底是什么?详细说明。

注意，我们可以在某些平台上使用CR或LF或CRLF来代表换行符，但在其他一些平台上它们不能代表换行符。详见wiki Newline。

LF: Multics, Unix and Unix-like systems (Linux, OS X, FreeBSD, AIX, Xenix, etc.), BeOS, Amiga, RISC OS, and others CR: Commodore 8-bit machines, Acorn BBC, ZX Spectrum, TRS-80, Apple II family, Oberon, the classic Mac OS up to version 9, MIT Lisp Machine and OS-9 RS: QNX pre-POSIX implementation 0x9B: Atari 8-bit machines using ATASCII variant of ASCII (155 in decimal) CR+LF: Microsoft Windows, DOS (MS-DOS, PC DOS, etc.), DEC TOPS-10, RT-11, CP/M, MP/M, Atari TOS, OS/2, Symbian OS, Palm OS, Amstrad CPC, and most other early non-Unix and non-IBM OSes LF+CR: Acorn BBC and RISC OS spooled text output.

Carriage return and line feed are also references to typewriters, in that the with a small push on the handle on the left side of the carriage (the place where the paper goes), the paper would rotate a small amount around the cylinder, advancing the document one line. If you had finished typing one line, and wanted to continue on to the next, you pushed harder, both advancing a line and sliding the carriage all the way to the right, then resuming typing left to right again as the carriage traveled with each keystroke. Needless to say, word-wrap was the default setting for all word processing of the era. P:D

Apart from above information, there is still an interesting history of LF (\n) and CR (\r). [Original author : 阮一峰 Source : http://www.ruanyifeng.com/blog/2006/04/post_213.html] Before computer came out, there was a type of teleprinter called Teletype Model 33. It can print 10 characters each second. But there is one problem with this, after finishing printing each line, it will take 0.2 second to move to next line, which is time of printing 2 characters. If a new characters is transferred during this 0.2 second, then this new character will be lost.

于是科学家们找到了解决这个问题的方法，他们在每行后面加了两个结尾字符，一个是“回车”，这是告诉打印机将打印头移到左边。另一个是“换行”，它告诉打印机将纸张上移一行。

后来，计算机变得流行起来，这两个概念都用在了计算机上。当时的存储设备很贵，所以有科学家说每行末尾加两个字很贵，一个就够了，所以用哪个就有一些争论。

在UNIX/Mac和Linux中，'\n'被放在每行的末尾，在Windows中，'\r\n'被放在每行的末尾。这种使用的结果是，如果在Windows中打开，UNIX/Mac中的文件将显示在一行中。而Windows中的文件如果在UNIX或Mac中打开，则每行末尾会有一个^M。

\r是回车，光标向后移动，就像我要做-一样

printf("stackoverflow\rnine")
ninekoverflow

表示已将光标移到“stackoverflow”的开头，并覆盖开始的4个字符，因为“nine”有4个字符长。

\n是新行字符，它改变行并将光标移到新行开头，如-

printf("stackoverflow\nnine")
stackoverflow
nine

\f是进给，它的用途已经过时了，但它被用于缩进

printf("stackoverflow\fnine")
stackoverflow
             nine

如果我这样写

printf("stackoverflow\fnine\fgreat")
stackoverflow
             nine
                 great