Git教程-理解Git跟踪修改

Git跟踪的是修改，不是文件

当前的readme.txt内容：

Git is a distributed version control system.
Git is free software distributed under the GPL.
Git has a mutable index called stage.

对其做一个修改：

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.

然后git add,查看git status：

$ git status
On branch master
Changes to be committed:
  (use "git reset HEAD ..." to unstage)

        modified:   readme.txt

再修改readme.txt：

$ cat 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.

此时git commit提交,提交的是第一次修改的，也就是提交的是存在了缓存区中的内容

$ git commit -m "git track changes"
[master abc33e9] git track changes
 1 file changed, 2 insertions(+), 1 deletion(-)

查看此时的status：

$ git status
On branch master
Changes not staged for commit:
  (use "git add ..." to update what will be committed)
  (use "git checkout -- ..." to discard changes in working directory)

        modified:   readme.txt

no changes added to commit (use "git add" and/or "git commit -a")

由于第二次的内容在工作区中，不在缓存区，所以显示第二次的修改没有被提交。

用git diff HEAD – readme.txt命令可以查看工作区（第二次修改的）和版本库（第一次修改的）里面最新版本的区别,可见第二次修改确实没有提交

diff --git a/readme.txt b/readme.txt
index db28b2c..9a8b341 100644
--- a/readme.txt
+++ b/readme.txt
@@ -1,4 +1,4 @@
 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.
\ No newline at end of file
+Git tracks changes of files.
\ No newline at end of file