CRLF和LF

目录：

1. 什么是CRLF和LF
2. 为什么要探究CRLF和LF
3. 三种方式处理的不同
4. 更多
5. 参考文献

1、什么是CRLF和LF

CRLF 是carriagereturnlinefeed的缩写。中文意思是回车换行。

LF是line feed的缩写，中文意思是换行。

2、为什么要探究CRLF和LF

在学习git软件，安装git到configuring the lien ending conversion时，有三个选项。

a. Checkout Windows-style,commit Unix-style line endings.

b.Checkout as-is,commit Unix-style line endings.

c.Checkout as-is,commit as-is line endings. 

这里面讲到了做两个操作(Checkout,Commit)的三种处理line endings的操作(Windows-style,Unix-style,As-is)。

为什么会出现这三种处理line endings（行尾结束符）呢？在Git的帮助页面给出了很好的解释。

Reference From:https://help.github.com/articles/dealing-with-line-endings 

If you're using Git to collaborate with others on GitHub, ensure that Git isproperly configured to handle line endings.

Every time you press return on your keyboard you're actuallyinserting an invisible character called a line ending . Historically, differentoperating systems have handled line endings differently.

When you view changes in a file, Git handles line endings in its own way.Since you're collaborating on projects with Git and GitHub, Git mightproduce unexpected results if, for example, you're working on a Windows machine,and your collaborator has made a change in OS X.

意思很好理解，就不翻译了。重视由于历史的原因，各种不同的操作系统在处理行尾结束符采取了不同的处理方法。而Git和GitHub

3、三种方式处理的不同

CRLF->Windows-style

LF->Unix Style

CR->Mac Style

CRLF表示句尾使用回车换行两个字符(即我们常在Windows编程时使用" "换行)

LF表示表示句尾，只使用换行.

CR表示只使用回车.

4、在Git中如何转换？

在Git通过下面的命令配置

$git config --global core.autocrlf true
# Configure Git on Windows to properly handle line endings

解释：core.autocrlf是git中负责处理line endings的变量，可以设置三个值--true,inout,false.

设置成三个值会有什么效果呢？

If core.autocrlf is set to true, that means that any time you add a file to the git repo that git thinks is a text file, it will turn all CRLF line endings to just LF before it stores it in the commit.。

设置为true，添加文件到git仓库时，git将其视为文本文件。他将把crlf变成lf。【2】

If core.autocrlf is set to false, no line-ending conversion is ever performed, so text files are checked in as-is. This usually works ok。【2】

设置为false时，line-endings将不做转换操作。文本文件保持原来的样子。

设置为input时，添加文件git仓库石，git把crlf编程lf。当有人Check代码时还是lf方式。因此在window操作系统下，不要使用这个设置。 

这是参考文献2给的解释希望能帮助大家。 

Yet another way to show how autocrlf works

1) true:             x -> LF -> CRLF
2) input:            x -> LF -> LF
3) false:            x -> x -> x

where x is either CRLF (windows-style) or LF (unix-style) and arrows stand for

file to commit -> repository -> checked out file

更多: 

更为复杂的配置命令见网站：https://www.kernel.org/pub/software/scm/git/docs/git-config.html

关于LF和CRLF讨论见：http://stackoverflow.com/questions/1967370/git-replacing-lf-with-crlf 

You can also provide a special --global flag, which makes Git usethe same settings for line endings across every local Git repository on your computer.

参考文献

【1】https://help.github.com/articles/dealing-with-line-endings

【2】http://stackoverflow.com/questions/1967370/git-replacing-lf-with-crlf 

作者：gexiaochuan122 发表于2014-4-22 16:43:38 原文链接