Git - Git使用帮助（上）

Git安装、配置以及文件添加.Git常用指令为add，commit，status，log

一．Git安装和配置
1.    在window中安装完成git后，打开“Git bash”，配置用户名
2.    git config –global user.name “myname”
git config –global user.email “myemail@xx.xx”
3.    mkdir gittest 创建一个版本库，在指定地方创建一个名为gittest的空目录。
4．pwd 显示当前目录
5. git init 把当前目录变成Git可管理的仓库（repository），里面生成一个 .git的目录，用来跟踪管理版本库

MINGW64 /d/Git/gittest
$ pwd
/d/Git/gittest
52136@CQCA52136 MINGW64 /d/Git (master)
$ cd gittest/

MINGW64 /d/Git/gittest
$ git init
Initialized empty Git repository in D:/Git/gittest/.git/

二、添加文件到Git库，两步：add和commit
1.git add mytest.txt 把mytest.txt文件添加到仓库，mytest.txt文件在gittest目录下，
mytest.txt内容为一行文字：
git learn.
没有消息返回，添加成功。 
MINGW64 /d/Git/gittest (master)
$ git add mytest.txt
2. git  commit –m “Create the test file” 把文件提交到仓库，并添加本次修改的说明
$ git commit -m "Create the test file"
[master (root-commit) 65ce3f4] Create the test file
 1 file changed, 1 insertion(+)
 create mode 100644 mytest.txt

三、版本管理；git status查看文件是否有修改，git diff查看修改信息
将mytest.txt文件修改为如下内容：
git learn.
Creted by xx.


1.    git status 查看当前文件状态，新修改的文件没有添加到仓库中
$ 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:   mytest.txt

no changes added to commit (use "git add" and/or "git commit -a")
2．git diff 查看对文件所做的修改，

$ git diff
diff --git a/mytest.txt b/mytest.txt
index 00388d0..a59e99a 100644
--- a/mytest.txt
+++ b/mytest.txt
@@ -1 +1,2 @@
-git learn.
\ No newline at end of file
+git learn.
+Creted by xx.
\ No newline at end of file

3.git add
4. git commit –m “add a new line”

$ git add mytest.txt

$ git commit -m "add a new line"
[master 8aee487] add a new line
1    file changed, 2 insertions(+), 1 deletion(-)

再次运行git status 后
$ git status
On branch master
nothing to commit, working tree clean


四、版本回退。git log 和git reset命令
1.git log 查看历史版本信息，由最近版本从上向下显示，添加—pretty=oneline参数简化输出内容
$ git log
commit 8aee4877b034b1371bdabe0495ea906ce0ea9371 (HEAD -> master)
Author: name <name@xxx.com.cn>
Date:   Mon Nov 13 18:18:11 2017 +0800

    add a new line

commit 65ce3f4af21274e46d83a48d57235a01ab420c12
Author: name <name@xxx.com.cn>
Date:   Mon Nov 13 18:03:49 2017 +0800

    Create the test file

$ git log --pretty=oneline
8aee4877b034b1371bdabe0495ea906ce0ea9371 (HEAD -> master) add a new line
65ce3f4af21274e46d83a48d57235a01ab420c12 Create the test file

2．git reset –hard HEAD^  回退上一版本， HEAD标识当前版本，HEAD^表示上一版本，HEAD^^倒数第二次版本，65ce3f4af21274e46d83a48d57235a01ab420c12 标识commit id
$ git reset --hard HEAD^
HEAD is now at 65ce3f4 Create the test file

MINGW64 /d/Git/gittest (master)
$ git log
commit 65ce3f4af21274e46d83a48d57235a01ab420c12 (HEAD -> master)
Author: name <name@xxx.com.cn>
Date:   Mon Nov 13 18:03:49 2017 +0800

    Create the test file
3. git reset --hard id回退到指定的版本，id可以只写commit id的前几位，git可自动查找
$ git reset --hard 8aee
HEAD is now at 8aee487 add a new line
4．git reflog 查看版本切换历史，通常在电脑关闭，git窗口关闭后查看切换记录
$ git reflog
8aee487 (HEAD -> master) HEAD@{0}: reset: moving to 8aee
65ce3f4 HEAD@{1}: reset: moving to HEAD^
8aee487 (HEAD -> master) HEAD@{2}: commit: add a new line
65ce3f4 HEAD@{3}: commit (initial): Create the test file

五．版本库（Repository）
工作区gittest目录中的隐藏目录.git为Git的版本库。暂存区（stage/index）保存于.git，Git在创建版本库后自动创建一个master分支，以及指向master的一个HEAD指针。
Git添加文件的两个步骤，add实际上是把文件修改添加到暂存区(stage)，commit提交更改，把暂存区的所有内容提交到当前分支（前述例子中的master）
六，修改撤销
1.    尚未add添加到暂存区：git checkout -- mytest.txt 撤销最后一次的修改（尚未add或commit），回到最后一次commit或add的状态
$ git checkout -- mytest.txt

MINGW64 /d/Git/gittest (master)
$ cat mytest.txt
git learn. 
2.    已add暂存区，尚未commit到版本库；git reset HEAD file 撤销暂存区的修改，两步：回退到HEAD，再checkout。
$ git add mytest.txt

MINGW64 /d/Git/gittest (master)
$ git status
On branch master
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   mytest.txt


MINGW64 /d/Git/gittest (master)
$ git reset HEAD mytest.txt
Unstaged changes after reset:
M       mytest.txt

MINGW64 /d/Git/gittest (master)
$ 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:   mytest.txt

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

MINGW64 /d/Git/gittest (master)
$ git checkout -- mytest.txt

MINGW64 /d/Git/gittest (master)
$ git status
On branch master
nothing to commit, working tree clean

七、文件删除
1.删除一个被add和commit的文件后，git status查看状态，git rm 删除，并且再次git commit，git checkout – deletefile 恢复误删的文件至最新版本