7.管理修改
[要理解的概念]为Git跟踪并管理的是修改，而非文件
什么是修改？比如你新增了一行，这就是一个修改，删除了一行，也是一个修改，更改了某些字符，也是一个修改，删了一些又加了一些，
也是一个修改，甚至创建 一个新文件，也算一个修改
如下图：
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[实践出真知]
第一次修改readme.txt
$ vim readme.txt #修改readme.txt 增加一行Git tracks changes. Git is a distributed version control system. Git is free software distributed under the GPL. Git has a mutable index called stage. Git tracks changes. $ git add readme.txt #提交到暂存区 $ git status #查看工作区所有文件的状态 On branch master Changes to be committed: (use "git reset HEAD <file>..." to unstage) modified: readme.txt
第二次修改readme.txt 未add提交到暂存区。
$ vim readme.txt Git is a distributed version control system. Git is free software distributed under the GPL. Git has a mutable index called stage. Git tracks changes of files.
提交暂存区的代码到仓库
$ git commit -m "git tracks changes" [master 4f2760d] git tracks changes 1 file changed, 1 insertion(+)
查看工作区的所有文件的状态
$ git status On branch master Changes not staged for commit: (use "git add <file>..." to update what will be committed) (use "git checkout -- <file>..." to discard changes in working directory) modified: readme.txt #第二次的修改没有被提交到仓库，因为未被add提交到暂存区，无法commit到仓库 no changes added to commit (use "git add" and/or "git commit -a")
原文：http://www.cnblogs.com/horizonli/p/5324606.html