Git 7.6 git branch 分支

--- title: Git 7.6 git branch 分支 tags: Git, 5x, 5x --- 7.6 0425 Git branch 分支 === # Examle 1 直線進行的分支 ## 1. git branch 列出所有分支 ```bash /Users/tingtinghsu/git-examples/git-branch1 tingdeAir:git-branch1 tingtinghsu$ git branch * master ``` ## 2. git branch `cat` 建立新分支 ```bash tingdeAir:git-branch1 tingtinghsu$ git branch cat /* 貼貼紙 */ * master ``` ## 3. git checkout `cat` 切換到cat分支 `HEAD`: 上帝視角 1. HEAD移動到cat貼紙，並且跟著cat 2. 專案會變成cat貼紙指到的Commit狀態 3. 目前cat跟master所在位置一樣 ```bash tingdeAir:git-branch1 tingtinghsu$ git checkout cat Switched to branch 'cat' tingdeAir:git-branch1 tingtinghsu$ git branch * cat master ``` ### 3-1 在`cat` branch送commit 使用checkout之後送commit 1. cat貼紙與HEAD往前移動(如下圖，`cat`分支變為粗體字) 3. 其他分支留在原地 ![圖:cat貼紙與HEAD往前移動](https://i.imgur.com/auRG8fF.png) ```bash tingdeAir:git-branch1 tingtinghsu$ git branch * cat master tingdeAir:git-branch1 tingtinghsu$ touch .keep tingdeAir:git-branch1 tingtinghsu$ git status On branch cat Untracked files: (use "git add <file>..." to include in what will be committed) .keep tingdeAir:git-branch1 tingtinghsu$ git add . tingdeAir:git-branch1 tingtinghsu$ git commit -m "add cat branch" [cat 8fded81] add cat branch 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 .keep tingdeAir:git-branch1 tingtinghsu$ git log --oneline 8fded81 add cat branch 865f98a add hello-world file e12d8ef add database.yml in config folder 85e7e30 add hello 657fce7 add container abb4f43 update index page cef6e40 create index page cc797cd init commit ``` ### 3-2 git merge 合併分支 (先切回master) 跟master很像的分支，合併時會使用fast-forward快轉（git圖示上master往前走，沒有小耳朵） 1. 切換回master分支 `git checkout master` - HEAD移動到master貼紙 - 專案會變成master貼紙指到的commit狀態 (如下圖，`master`分支變回粗體字) ![圖:專案會變成master貼紙指到的commit狀態](https://i.imgur.com/K1nTCbo.png) 2. 合併cat分支 `git merge cat` - master與HEAD移動到cat貼紙的所在地 - 快轉(Fast-forward)合併 => 合併分支可以看成在移動貼紙(如下圖，`master`貼紙移動到與`cat`貼紙相同的commit) ![](https://i.imgur.com/b9tmAjn.png) ```bash tingdeAir:git-branch1 tingtinghsu$ git branch * cat master tingdeAir:git-branch1 tingtinghsu$ git checkout master Switched to branch 'master' tingdeAir:git-branch1 tingtinghsu$ git merge cat Updating 865f98a..8fded81 Fast-forward .keep | 0 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 .keep tingdeAir:git-branch1 tingtinghsu$ git log --oneline 8fded81 add cat branch 865f98a add hello-world file e12d8ef add database.yml in config folder 85e7e30 add hello 657fce7 add container abb4f43 update index page cef6e40 create index page cc797cd init commit ``` ## 4. `git branch -d`刪掉已合併的分支 1. 把cat貼紙撕起來 2. Commit 或是檔案不會因此受到影響 => **Git 的本體是commit, 分支只是浮雲** ```bash tingdeAir:git-branch1 tingtinghsu$ git branch -d cat Deleted branch cat (was 8fded81). ``` # Examle 2 複雜一點的分支 y型merge ## 1. git branch `dog` 建立新分支在目前HEAD所在地貼dog貼紙 ```bash tingdeAir:git-branch1 tingtinghsu$ git branch dog tingdeAir:git-branch1 tingtinghsu$ git branch dog * master rabbit tingdeAir:git-branch1 tingtinghsu$ ``` ## 2. git checkout `dog` 切換到dog分支 1. HEAD移動到dog分支 2. 專案會變成dog貼紙指到的Commit狀態 3. 目前dog跟master所在位置一樣 ```bash tingdeAir:git-branch1 tingtinghsu$ git checkout dog Switched to branch 'dog' tingdeAir:git-branch1 tingtinghsu$ git branch * dog master rabbit ``` ### 2-1 在`dog` branch送commit 再進行一次存檔 1. dog貼紙與HEAD往前移動 2. 其他分支貼紙留在原地 ![dog貼紙與HEAD往前移動](https://i.imgur.com/c0XA4yv.png) HEAD像是令牌，只有領到令牌的分支才可以往前移動 ```bash tingdeAir:git-branch1 tingtinghsu$ git commit -m "add dog 1" [dog e560a0e] add dog 1 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 .keepdog ``` ### 2-2 在`dog` branch再送一次commit ```bash tingdeAir:git-branch1 tingtinghsu$ git add . tingdeAir:git-branch1 tingtinghsu$ git commit -m "add dog 2" [dog 3f699df] add dog 2 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 .keeptwodogs ``` 第二個分支長太大，這時候的合併就沒辦法fast forward了 ![分支長太大的合併就沒辦法fast forward](https://i.imgur.com/63w6piS.png) ### 2-3. git merge `rabbit` : 在dog分支合併rabbit分支 rabbit分支也commit過一次，若此時dog分支想要合併rabbit分支: 1.長出一個合併的commit (dog和rabbit分支的公證人) 2.dog貼紙和HEAD往新的commit移動 ![合併分支時產生小耳朵](https://i.imgur.com/fGz2BDC.png) ```bash tingdeAir:git-branch1 tingtinghsu$ git checkout rabbit Switched to branch 'rabbit' tingdeAir:git-branch1 tingtinghsu$ ls config hello.html index.html welcome.html tingdeAir:git-branch1 tingtinghsu$ touch rabbit tingdeAir:git-branch1 tingtinghsu$ git add . tingdeAir:git-branch1 tingtinghsu$ git commit -m "add rabbit" [rabbit 6001538] add rabbit 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 rabbit tingdeAir:git-branch1 tingtinghsu$ git checkout dog Switched to branch 'dog' tingdeAir:git-branch1 tingtinghsu$ git merge rabbit Merge made by the 'recursive' strategy. rabbit | 0 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 rabbit ``` ＊在Sourcetree打勾Checkout New Branch，代表建立分支之後立即切換過去該branch。 # Example 3 讓合併的節點消失掉`git rebase` `git rebase`: 變換根基/嫁接注意: 在git的世界裡，commit沒有辦法刪除，但透過`git rebase`可以將歷史commit記錄變成直線。現在有`dog`與`bird`分支 ![dog分支與bird分支](https://i.imgur.com/qxDoNGf.png) 在HEAD是dog, `git rebase bird `: dog踩在bird分支的頭上 1. 複製一份dog的commit接到bird的commit後面，形成新的commit 2. HEAD移動到新的commit 3. dog貼紙移動到新的commit, HEAD指向bird貼紙 4. bird貼紙從舊的分支commit脫離（如下圖：bird分支已消失，歷史紀錄變成直線） ![bird分支的舊commit脫離](https://i.imgur.com/cPwVtqr.png) ```bash tingdeAir:git-branch1 tingtinghsu$ git rebase bird First, rewinding head to replay your work on top of it... Applying: add dog3 ``` # merge和rebase的使用時機 rebase 優點: 拿來整理過多節點的時候，把節點拉成同條缺點: 看不太出來歷史軌跡

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