< 笔记 > Git

04 Git 版本控制

By Kevin Song

• 04-01 版本回退
• 04-02 工作区和暂存区
• 04-03 管理修改
• 04-04 撤销修改
• 04-05 删除文件

git status： 查看仓库有没有被修改

$ git statusOn branch masternothing to commit, working directory clean

修改 readme.txt 后再次使用 git status

Git is a distributed version control system.Git is free software.

$ git statusOn branch masterChanges 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.txtno changes added to commit (use "git add" and/or "git commit -a")

git diff： 查看文件修改了什么内容

$ git diff readme.txtdiff --git a/readme.txt b/readme.txtindex d8036c1..013b5bc 100644--- a/readme.txt+++ b/readme.txt@@ -1,2 +1,2 @@-Git is a version control system.+Git is a distributed version control system. Git is free software.\ No newline at end of file

确认提交

• git add

$ git add readme.txt

• git commit

$ git commit -m "add distributed"[master e6d9050] add distributed 1 file changed, 1 insertion(+), 1 deletion(-)

04-01 版本回退

修改readme.txt如下

Git is a distributed version control system.Git is free software distributed under the GPL.

提交

$ git add readme.txt$ git commit -m "append GPL"[master a9d0c7a] append GPL 1 file changed, 1 insertion(+), 1 deletion(-)

现在仓库有三个版本

版本1：wrote a readme file

Git is a version control system.Git is free software.

版本2：add distributed

Git is a distributed version control system.Git is free software.

版本3：append GPL

Git is a distributed version control system.Git is free software distributed under the GPL.

git log： 查看版本

git log –pretty=oneline： 查看简单版本

$ git logcommit a9d0c7a4f503c94076a60980657d3198b55cdba3Author: Kevin Song <[e-mail]>Date:   Thu Oct 12 18:30:17 2017 +0800    append GPLcommit e6d9050da9cdb141c33b865946b38bf3e3a7ad56Author: Kevin Song <[e-mail]>Date:   Thu Oct 12 18:27:04 2017 +0800    add distributedcommit 2f74cef7a2afece8ce64b5f182850f216e109702Author: Kevin Song <[e-mail]>Date:   Wed Oct 11 19:04:52 2017 +0800    wrote a readme file

版本回退 git reset

$ git reset --hard HEAD^HEAD is now at e6d9050 add distributed

版本前进 git reset

$ git reset --hard a9d0c7a4fHEAD is now at a9d0c7a append GPL

• HEAD 当前版本
• HEAD^ 上一个版本
• HEAD^^ 上上个版本
• …
• HEAD~100 上100个版本

如果忘记版本号无法前进，用 git reflog 查看所有操作

$ git refloga9d0c7a HEAD@{0}: reset: moving to a9d0c7a4fe6d9050 HEAD@{1}: reset: moving to HEAD^a9d0c7a HEAD@{2}: commit: append GPLe6d9050 HEAD@{3}: commit: add distributed2f74cef HEAD@{4}: commit (initial): wrote a readme file

04-02 工作区和暂存区

• 工作区（Working Directory）：learngit
• 版本库（Repository）：.git
  
  • 暂存区：stage
  • 分支：branch

git add 就是把文件从工作区移动到暂存区

git commit 就是把文件从暂存区提交到分支

示例

1 . 修改 readme.txt

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

2 . 新增一个 LICENSE 文件

git status 查看状态

$ git statusOn branch masterChanges 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.txtUntracked files:  (use "git add <file>..." to include in what will be committed)        LICENSEno changes added to commit (use "git add" and/or "git commit -a")

3 . 把两个文件add之后再次查看状态

$ git statusOn branch masterChanges to be committed:  (use "git reset HEAD <file>..." to unstage)        new file:   LICENSE        modified:   readme.txt

4 . 提交到分支

$ git commit -m "understand how stage works"[master b012805] understand how stage works 2 files changed, 2 insertions(+), 1 deletion(-) create mode 100644 LICENSE

04-03 管理修改

Git 的优秀之处：跟踪并管理的是修改，而不是文件

1 . 修改 readme.txt

$ cat readme.txtGit is a distributed version control system.Git is free software distributed under the GPL.Git has a mutable index called stage.Git tracks changes.

2 . 添加并查看状态

$ git add readme.txtAdministrator@2013-20150101XS MINGW64 /d/Git/learngit (master)$ git statusOn branch masterChanges to be committed:  (use "git reset HEAD <file>..." to unstage)        modified:   readme.txt

3 . 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.

4 . 提交

$ git commit -m "git tracks changes"[master 0792507] git tracks changes 1 file changed, 2 insertions(+), 1 deletion(-)

5 . 查看状态发现工作区并不是干净的

$ git statusOn branch masterChanges 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.txtno changes added to commit (use "git add" and/or "git commit -a")

原因：第二次修改没有 add 到暂存区

第一次修改 -> git add -> 第二次修改 -> git commit

正解：第二次修改 add 到暂存区，commit合并两次修改一并提交

第一次修改 -> git add -> 第二次修改 -> git add -> git commit

结论： commit 之前一定要 add 到暂存区

04-04 撤销修改

• add 前撤销修改： git checkout
• add 后撤销修改：git reset HEAD file
• commit 后撤销修改：版本回退

add 前撤销修改： git checkout

把文件在工作区的修改全部撤销

• add 前 修改 后 checkout（文件自修改后还没有被放到暂存区）
  
  • 撤销修改：回到和版本库一样的状态
  • （回到上次 git commit 的状态）
• add 后 修改 后 checkout（文件自修改后已经被被放到暂存区）
  
  • 撤销修改：回到添加到暂存区后的状态
  • （回到上次 git add 的状态）

1 . 修改文件readme.txt

$ cat readme.txtGit 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.My stupid boss still prefers SVN.

2 . 撤销修改

$ git checkout -- readme.txt

3 . 查看文件

$ cat readme.txtGit 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.

add 后撤销修改：git reset HEAD file

1 . 修改文件 readme.txt 并且 add 到暂存区

$ cat readme.txtGit 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.My stupid boss still prefers SVN.$ git add readme.txt

2 . git reset HEAD file 把暂存区的修改撤销（unstage），重新放回工作区

$ git reset HEAD readme.txtUnstaged changes after reset:M       readme.txt

3 . 丢弃工作区的修改

$ git checkout -- readme.txt$ git status# On branch masternothing to commit (working directory clean)

04-05 删除文件

1 . 先添加一个新文件test.txt到Git并且提交：

$ git add test.txt$ git commit -m "add test.txt"[master 94cdc44] add test.txt 1 file changed, 1 insertion(+) create mode 100644 test.txt

2 . 工作区删除文件

$ rm test.txt

3 . 版本库删除文件

$ git rm test.txtrm 'test.txt'$ git commit -m "remove test.txt"[master d17efd8] remove test.txt 1 file changed, 1 deletion(-) delete mode 100644 test.txt

误删恢复

$ git checkout -- test.txt

git checkout 本质：用版本库里的版本替换工作区的版本