# Git

## tag,branch,submodule 基本使用

### Tag[来源1](https://github.com/git-tips/tips#create-local-tag),[来源2](https://github.com/k88hudson/git-flight-rules)

```bash
    git tag <tag-name> # create local tag
    git tag -d <tag-name> # delete local tag
    git push origin :refs/tags/<tag-name> # delete remote tag
    git fsck --unreachable | grep tag && git update-ref refs/tags/<tag_name> <hash> # recover a deleted tag

    git describe --tags --abbrev=0 # show the most recent tag on the current branch
    git tag --contains <commitid> # find all tags containing a specific commit
```

### Branch

分支不能含空格，见[这里](https://stackoverflow.com/a/6619113)。

#### [本地和远程创建空分支](https://stackoverflow.com/a/34100189)

```bash
    # UPDATE(git > 2.27)
    git switch --orphan <new branch>
    git commit --allow-empty -m "Initial commit on orphan branch"
    git push -u origin <new branch>

    ## Old Way

    # local
    git checkout --orphan empty-branch
    git rm -rf .
    # remote
    git commit --allow-empty -m "root commit"
    git push origin empty-branch
```

#### 本地和远程删除分支

```bash
    # delete branch locally
    git branch -d localBranchName
    # delete a local branch that has not been merged to the current branch or an upstream
    git branch -D localBranchName

    # delete branch remotely
    git push origin --delete remoteBranchName
    # same as
    git push origin :remoteBranchName

    # delete multiple branches
    git branch | grep 'fix/' | xargs git branch -d

    # rename current branch
    git branch -m new-name
    # rename a different(local) branch
    git branch -m old-name new-name

    # delete the old-name remote branch and push the new-name local branch
    git push origin :old_name new_name
```

#### 克隆特定远程分支

```bash
    git clone --branch <branchname> <remote-repo-url>
```

#### 删除仅存在本地（远程仓库中不存在）的分支

```bash
    $ git branch -a
    * main

      remotes/origin/articles-main
      remotes/origin/gh-pages
      remotes/origin/main

    # remote branch articles-main, gh-pages has been deleted
    $ git remote prune origin
    Pruning origin
    URL: git@github.com:tianheg/wiki.git

    * [pruned] origin/articles-main
    * [pruned] origin/gh-pages
```

Others:

```bash
    git branch # list local branches
    git branch -r # list remote branches
    git branch -a # list local and remote branches
    git checkout -b <branch> <SHA1_OF_COMMIT> # create a branch from a commit
```

### Submodule

```bash
    # clone all submodules
    git clone --recursive git://github.com/foo/bar.git
    # already cloned
    git submodule update --init --recursive
```

#### 移除 Submodule

```bash
    git submodule deinit submodulename
    git rm submodulename
    git rm --cached submodulename
    rm -rf .git/modules/submodulename
```

## 移除子模块

https://stackoverflow.com/a/1260982/12539782

仓库中只有一个子模块：

```
    git rm <path-to-submodule>
    rm .gitmodules
    rm -rf .git/modules
    git config --remove-section submodule.<path-to-submodule>
```

## 修改 commit 信息

https://stackoverflow.com/a/1186549/12539782

想修改 `bbc643cd` 的信息

```
    git rebase --interactive 'bbc643cd^'
```

在默认编辑器打开后，将 pick 改为 r/reword 后保存，然后就可以修改 commit
信息了。

## 强制从远程仓库拉取内容到本地

https://stackoverflow.com/q/70710729/12539782

```
    git remote -v
    # origin  git@github.com:tianheg/running_page.git (fetch)
    # origin  git@github.com:tianheg/running_page.git (push)
    # upstream        git@github.com:yihong0618/running_page.git (fetch)
    # upstream        git@github.com:yihong0618/running_page.git (push)
    git reset --hard upstream/master
```

## Gitea

### 原生

选择：

- Gitea 1.16.8
- MariaDB 10.7.4

#### 配置数据库

https://docs.gitea.io/en-us/database-prep/

```
    pacman -S mariadb
```

修改 `bind-address` ，登录 root 用户下的数据库。

本地安装 Gitea：

```sql
    SET old_passwords=0;
    CREATE USER 'gitea' IDENTIFIED BY 'gitea';
    CREATE DATABASE giteadb CHARACTER SET 'utf8mb4' COLLATE 'utf8mb4_unicode_ci';
    GRANT ALL PRIVILEGES ON giteadb.* TO 'gitea';
    FLUSH PRIVILEGES;
```

#### 安装 Gitea

```
    pacman -S gitea
    gitea # 浏览器打开 http://localhost:3000 进行配置
    sudo cp /etc/gitea/app.example.ini /etc/gitea/app.ini
    systemctl enable --now gitea
```

无法打开 gitea 服务。无法使用，安装失败。

refer:

1. https://forum.hostea.org/t/howto-gitea-upgrades-a-guide-for-admins/39

### Docker

https://docs.gitea.io/en-us/install-with-docker-rootless/

## 理解 Merge & Rebase

1. https://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging
2. https://git-scm.com/book/en/v2/Git-Tools-Advanced-Merging#_advanced_merging
3. https://git-scm.com/book/en/v2/Git-Branching-Rebasing

Merge 是起初两条 branches 后来合并为一条，与此同时保留被合并的分支；

Rebase 则是合并后不保留被合并的分支。

第 2 个链接中的例子还没有完全理解。

> Do not rebase commits that exist outside your repository and that
> people may have based work on.
>
> If you only ever rebase commits that have never left your own
> computer, you'll be just fine. If you rebase commits that have been
> pushed, but that no one else has based commits from, you'll also be
> fine. If you rebase commits that have already been pushed publicly,
> and people may have based work on those commits, then you may be in
> for some frustrating trouble, and the scorn of your teammates.

## 配置代理

```
    git config --global http.proxy http://<proxy-server>:<port>/
    git config --global https.proxy https://<proxy-server>:<port>/
```

---

参考资料：

1. https://gist.github.com/coin8086/7228b177221f6db913933021ac33bb92
2. https://cms-sw.github.io/tutorial-proxy.html
3. https://riptutorial.com/git/example/17900/clone-using-a-proxy
4. https://stackoverflow.com/q/128035/12539782

## 对分支重命名（本地 & 远程）

[How to Rename Git Local and Remote Branches](https://www.w3docs.com/snippets/git/how-to-rename-git-local-and-remote-branches.html)

```
    ## Local
    git branch -m <old-name> <new-name>
    ## Remote
    # delete remote branch
    git push origin --delete <old-name> # or git push origin :<old-name>
    # push new remote branch
    git push origin <new-name>
    # To reset the upstream branch for the new-name local branch use the -u flag
    git push origin -u <new-name>
```

## 重命名远程代号（origin）

https://support.beanstalkapp.com/article/1000-how-do-i-rename-an-existing-git-remote

```bash
    git remote rename origin upstream
```

## 在历史中查找文件

```bash
    git log --all --full-history -- <FILE_PATH>
    git log --all --full-history -- feeds.csv
```

## 设置全局 gitignore

```bash
    git config --global core.excludesfile '~/.gitignore'
```

## 子模块改变地址

https://git-scm.com/docs/git-submodule#Documentation/git-submodule.txt-sync--recursive--ltpathgt82308203

```bash
    # step 1
    # 手动改变 .gitmodules 中的 url
    # step 2
    git submodule sync
```

## 子模块更新

https://git-scm.com/book/en/v2/Git-Tools-Submodules

```bash
    # way 1
    git submodule init
    git submodule update
    # way 2
    git submodule update --init
    # way 3
    git submodule update --init --recursive # 会 clone 所有子模块（也包括子模块的子模块）
```

## 与上游仓库同步

```bash
    git checkout -b new-branch main
    git pull https://github.com/yihong0618/running_page.git upstream-branch
    # after pulling, fix the CONFLICT
    git checkout main
    git merge --no-ff new-branch
    git push origin main
```

## 使用 dura 每 5s 备份一次仓库

https://github.com/tkellogg/dura

### 配置

```bash
    # arch linux
    yay -S dura-git
    dura serve & # Run it in the background
    cd /git/repo/
    dura watch

    ## watch all git repo under /home/user
    find ~ -type d -name .git -prune | xargs -I= sh -c "cd =/..; dura watch" # BE CAREFUL!!! use when knowing what you are doing
```

## 不 Merge

```bash
# Since git version 1.7.4
git merge --abort
# prior git versions
git reset --merge
```

## 等待整理

- [Idiot proof git](https://softwaredoug.com/blog/2022/11/09/idiot-proof-git-aliases.html)

## Change the author and committer name/email for multiple commits

<https://stackoverflow.com/a/1320317/12539782>

**NOTE: This operation will modify [SHA-1](https://git-scm.com/docs/hash-function-transition/), and commits date.**

Steps:

```bash
git config --global user.name "New Author Name"
git config --global user.email "email@address.example"
git rebase -r --root --exec "git commit --amend --no-edit --reset-author"
```

## Add Files to A Commit Except A Single File

<https://stackoverflow.com/a/4475506/12539782>

```bash
git add -u
git reset -- file_excepted
```

## Remove Untracked Files from Working Tree
<https://stackoverflow.com/a/64966/12539782>

```bash
# Print out the list of files and directories which will be removed (dry run)
git clean -n -d
# Delete the files from the repository
git clean -f
```

## Push Two Remotes
<https://stackoverflow.com/a/14290145>

```bash
git remote set-url --add --push origin git://original/repo.git
git remote set-url --add --push origin git://another/repo.git
```

## Write good commits

好的 commit 的作用：

1. 帮助理解本次操作内容
2. 加速和简化 code reviews
3. 解释不能只用代码来描述的“为什么”
4. 帮助以后的维护者，弄清楚为什么以及改变是怎样产生的，使故障排除和调试更容易

```text
feat: add hat wobble
^--^ ^------------^
| |
| |-> Summary in present tense.
|
|------->Type: chore, docs, feat(option), fix, refactor, style, test, (!)BREAKING CHANGE, build, ci, perf, test
```

[例子](https://sparkbox.com/foundry/semantic_commit_messages)：

- chore: add Oyster build script
- docs: explain hat wobble
- feat: add beta sequence
- feat(lang): add polish language
- fix: remove broken confirmation message
- refactor: share logic between 4d3d3d3 and flarhgunnstow
- style: convert tabs to spaces
- test: ensure Tayne retains clothing

GitHub 例子

```
    git commit -m "fix: accept current change
    https://github.com/tianheg/blog/blob/26af0419337014dea93ada9bf4a3d8bbbcc39619/layouts/shortcodes/music.html#L1"

    git commit -m "add: ...
    close #123"
```

更多资料见[这里](https://www.conventionalcommits.org/en/v1.0.0/#summary)。

## 如何从 Git 仓库中完全移除文件

请注意：不要在重要仓库中尝试，可以先新建一个测试 Git
仓库，以熟悉操作步骤（实际上只有一行命令）。

能够达到我的目的的命令（[来源](https://stackoverflow.com/a/52643437)）：

```
    git filter-branch --index-filter "git rm -rf --cached --ignore-unmatch path_to_file" HEAD
    git push -f
```

当使用 `filter-branch` 命令时，出现以下提示：

```
    WARNING: git-filter-branch has a glut of gotchas generating mangled history
             rewrites.  Hit Ctrl-C before proceeding to abort, then use an
             alternative filtering tool such as 'git filter-repo'
             (https://github.com/newren/git-filter-repo/) instead.  See the
             filter-branch manual page for more details; to squelch this warning,
             set FILTER_BRANCH_SQUELCH_WARNING=1.
```

大意就是说，`filter-branch` 命令有大量陷阱，会把已有的历史弄乱。按
Ctrl+C 可在未执行命令以前取消，然后使用另一个可供选择的筛选工具
[git filter-repo](https://github.com/newren/git-filter-repo)。查看
`filter-branch` 的手册获取更多信息，略去警告需设置
=FILTER_BRANCH_SQUELCH_WARNING=1=。

### 了解 `git filter-repo`

<https://github.com/newren/git-filter-repo>

`git filter-repo` 是一个用于重写 Git 仓库历史的多功能工具。它和
`git filter-branch`
差不多，但是没有导致性能下降的问题，它的功能更强大，而且它的设计可以扩展可用性，而不是简单的重写情况。=git
filter-repo= 现在被 Git 项目推荐，用于代替 `git filter-branch` 。

```
    sudo pacman -S git-filter-repo # 安装

    ### 演示使用方法
    git init test_git_filter_repo && cd $_ # 新建名为 test_git_filter_repo 的 Git 仓库，并打开
    touch test # 新建文件
    git add test # 添加到暂存区
    git commit -m "message" # 提交至 Git 仓库
    git log # 检查日志
    git filter-repo --path test --force --invert-paths # 删除包含 test 的历史
    git log # 检查结果：无 commit 提交
    ls -a # 没有文件 test
```

以上命令行中的演示，是使用 `git filter-repo`
移除文件的过程，谨记：不要直接在生产环境或重要仓库使用，要先确保自己知道某个命令的执行结果。
## 云服务器配置 Git 仓库托管并使用 Git Hooks 自动执行脚本

上文见[[hugo-deploy-to-server|部署 Hugo 博客到 Ubuntu 服务器]]。

之前的博客更新思路是，本地提交修改至
GitHub，再登录云服务器，手动执行脚本，达到更新博客内容的目的。但是，从
GitHub 拉取代码较慢，于是想到可以把本地的更改同时推送到 GitHub
和云服务器。再通过 Git Hooks
自动执行「更新博客」的脚本，以此达到提升效率的目的。

### 更新 Git 至最新版本

云服务器的系统是 Ubuntu 20.04，所以可以通过以下命令安装 Git 的最新版本：

```bash
    add-apt-repository ppa:git-core/ppa
    apt update
    apt install git
```

### 创建 Git 用户

```bash
    adduser git # note difference with useradd
    passwd git # add password for git user
    sudo visudo
```

修改 `/etc/sudoers` ：

```
    root    ALL=(ALL)       ALL
    ubuntu  ALL=(ALL:ALL) NOPASSWD: ALL
    git  ALL=(ALL:ALL) NOPASSWD: ALL # add
```

### 配置 ssh 公钥

在本地主机执行以下命令：

```bash
    ssh-keygen -t ed25519 -C "email"
```

会生成两个文件：id_ed25519 和 id_ed25519.pub。将 id_ed25519.pub
文件里的内容复制到云服务器的 authorized_keys 文件中：

```bash
    su git
    mkdir ~/.ssh
    vim ~/.ssh/authorized_keys
```

然后在本地添加私钥：

```bash
    ssh-add ~/.ssh/ssh_rsa
```

如果不添加私钥，还是提示输入密码。

注意： =~= 代表 `/home/git` 。只有 git 用户才能使用这个公钥。

修改权限：

```bash
    cd ~
    chmod 600 .ssh/authorized_keys
    chmod 700 .ssh
```

本地测试 git 服务：

```bash
    ssh -v git@server-ip # Server public network IP
```

### 创建博客文件夹

```bash
    su root # switch to root user
    mkdir /home/hugo
    chown git:git -R /home/hugo
```

### 更改站点目录权限

```bash
    sudo chown git:git -R /var/www/hugo # for git hook
```

### 创建 bare 仓库并配置 Git Hook

```bash
    su root
    cd /home/git
    git init --bare blog.git
    chown git:git -R blog.git
    vim blog.git/hooks/post-receive
    chmod +x blog.git/hooks/post-receive
```

新建文件 `blog.git/hooks/post-receive` ：

```
    #!/bin/sh
    git --work-tree=/home/hugo --git-dir=/home/git/blog.git checkout -f
    cd /var/www/hugo
    rm -rf * # 删除文件夹下的所有文件以保持最新
    cd /home/hugo
    hugo --minify -d /var/www/hugo
```

### 本地配置云服务器仓库

```bash
    git remote add origin git@server-ip:/home/git/blog.git
    git push -u origin main # first push
```

### 使用 Docker 配置 Hugo 部署

```bash
    #!/bin/sh

    git --work-tree=/home/www --git-dir=/home/git/blog.git checkout -f
    cd /home/www/public
    sudo rm -rf * # 删除文件夹下的所有文件以保持最新 & 通过 Docker 生成文件权限为 root 需要加 sudo
    cd /home/git/docker-blog
    docker compose up -d
```

`/home/git/docker-blog` ：

```bash
    docker-compose.yml  nginx.conf
```

`docker-compose.yml` ：

```
    version: "3.9"

    services:
      nginx:
        image: nginx:stable
        volumes:
          - $PWD/nginx.conf:/etc/nginx/nginx.conf
          - /etc/letsencrypt:/etc/letsencrypt
          - /home/www/public:/home/www/public
        ports:
          - "80:80"
          - "443:443"

      blog:
        image: tianheg/hugo:0.98.0
        volumes:
          - /home/www:/home/git
          - /home/www/public:/output
        environment:
          - HUGO_BASEURL=https://www.yidajiabei.xyz/
```

---

参考资料

1. <https://segmentfault.com/a/1190000039676421>
2. [[https://www.saintsjd.com/2011/01/what-is-a-bare-git-repository/]
## 只 clone 远程 Git repo 的一部分
- https://stackoverflow.com/a/52269934/12539782
- https://www.git-scm.com/docs/git-clone
```bash
git clone --depth 1 --filter=blob:none --sparse REPOSITORY_URL
cd DIRECTORY_NAME
git sparse-checkout init --cone
git sparse-checkout set DIRECTORY_NAME
```
## 从历史commit中删除特定文件

[Removing sensitive data from a repository - GitHub Docs](https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/removing-sensitive-data-from-a-repository)

```bash
git filter-repo --invert-paths --path PATH-TO-YOUR-FILE-WANT-TO-DELETE
git push origin --force --tags
```
## 查询commit msg
```bash
git log --grep="content_to_search"
git log --grep="html5"
```
## [Git - Reference](https://git-scm.com/docs)

### Guide - [gitcredentials[7](https://git-scm.com/docs/git#Documentation/git.txt-ahrefdocsgitcredentialsgitcredentials7a)]

<https://git-scm.com/docs/gitcredentials>

#### Credential 的描述

Git 有时需要来自用户的凭证来执行操作；例如，为了通过 HTTP
访问远程存储库，它可能需要请求用户名和密码。本手册描述了 Git
用于请求这些凭据的机制，以及避免重复输入这些凭据的一些特性。

#### 请求凭证

在未定义凭证助手（credential helpers）的情况下，Git
会采用一下策略得到用户名和密码：

1. 如果设置了 `GIT_ASKPASS`
   环境变量，变量指定的程序会被触发。命令行会输出一个合理的提示，提醒用户输入用户名和密码
2. 如果设置了 `core.askPass` 配置变量，它的行为如 1 所见
3. 如果设置了 `SSH_ASKPASS` 环境变量，它的行为如 1 所见
4. 否则，终端会提示用户

#### 避免冗杂

重复输入某些凭证，令人讨厌。Git 提供了两种解决办法：

1. 用于给定验证上下文的用户名的静态配置
2. 凭据助手可以缓存或存储密码，或者与系统密码钱包或钥匙链进行交互

---

<https://stackoverflow.com/a/51327559>

Git Credential 是为了保存用户名和密码而存在的，然而最安全的办法还是使用
SSH 密钥，不使用用户名和密码。

#### 使用 SSH 密钥

创建好一个 SSH
密钥对，私钥保存在本地，公钥存放在目标服务器。在本地添加私钥到 ssh-agent
：

```bash
    ssh-add ~/.ssh/id_rsa
```

#### Caching

```bash
    git config --global credential.helper cache
    # or
    git config --global credential.helper 'cache --timeout=3600'
```

#### Store

使用该选项，会将用户名和密码保存为纯文本，容易被窃取了。

```bash
    git config credential.helper store
```