Everything I should know about Git

reference:

廖雪峰 - Git教程

Coursera - Server-side Development with NodeJS, Express and MongoDB

0. Git Diagram

工作区(Working Directory) --add--> 暂存区(Staging area) --commit--> Master

HEAD refers to master

1. Global Configuration for Git

• Check to make sure that Git is installed and available on the command line, by typing the following at the command prompt:

git --version

• To configure your user name to be used by Git, type the following at the prompt:

git config --global user.name "Your Name"

• To configure your email to be used by Git, type the following at the prompt:

git config --global user.email <your email address>

• Check your default Git global configuration:

git config --list

2. Start

• Initializes the current folder as a git repository, just go to the folder and type the following at the prompt:

git init

Now the folder will be mark as a master

• Current status of the foler:
  • current branch
  • untracked files: files that are not been added to Git repository. Use add to add.
  • Changes not staged for commit: still use add to update
  • changes to be committed: files listed below are ready to be committed

git status

• See change details of a file:

git diff <file>

• Add files to staging area:

git add <file(s)/folder(s)>
git add . # the "." means all files

• After adding some files, you can commit the current state of the folder into Git repository:

git commit
# use -m <message> to add message

• Show the brief log of all the commits with messages

git log --oneline

3. Checkout/Reset/Restore

• Discard changes of the last commit, and checkout the file from an older commit. last commit -> any commit (staged)

git checkout <commit> <file>
# commit means commit id, using first several chars is ok

The file changes will be automatically set into the staging area, all you need to do is submitting.

• Reset a file from staged to untracked: staged -> untracked

git reset <commit [default=HEAD]> <file>

This command essentially has deeper meaning: You can return to past versions by config the <commit>.

HEAD: current version; HEAD^: previous version; HEAD^^: previous previous version...;HEAD-100: 100 versions before

• Reset the staging area to untracked. (Just status, not actually discarding your changes on the files)

git reset

• Discard changes of an untracked file: untracked -> last commit

git restore <file>
# or
git checkout -- <file>

• Return to a future version? Still use commit id as reference in git reset. But how to know the commit id of a future version? Use reflog to see command history.

git reflog

场景1：当你改乱了工作区某个文件的内容，想直接丢弃工作区的修改时，用命令git checkout -- <file>或者git restore <file>。

场景2：当你不但改乱了工作区某个文件的内容，还添加到了暂存区时，想丢弃修改，分两步，第一步用命令git reset HEAD <file>，就回到了场景1，第二步按场景1操作。

场景3：已经提交了不合适的修改到版本库时，想要撤销本次提交，用git reset HEAD^，不过前提是没有推送到远程库。

Github

###0. Connect with your Github account using SSH

1. Connect with a remote repo

• Suppose you have a blank repo on Github, and an existing repo on your computer
• Connect local repo with a remote one:

git remote add origin [email protected]:username/repoName.git

origin is the default name of a remote repo.

• Push local repo to the remote one:

git push -u origin master

command -u is for: Branch 'master' set up to track remote branch 'master' from 'origin'.

After the first push, you don't need the -u.

git push origin master

• Show info of remote repo:

git remote -v

• Disconnect remote repo by name:

git remote rm <name>

2. Clone an existing remote repo

git clone [email protected]:username/repoName.git

Instead of ssh, https is also available.

Branch

• Create a new branch

git branch <name>

• Switch to a branch

git switch <name>

• Show branchs:

git branch

Current bransh has a * ahead.

• Merge branch to current one:

git merge <name>

• Delete a branch

git branch -d <name>

Solve conflicts

When you merge a branch to current branch, sometimes there are conflicts.

The conflicts will be directly showed in the files as:

<<<<<<< HEAD
Creating a new branch is quick & simple.
=======
Creating a new branch is quick AND simple.
>>>>>>> feature1

• Just fix it manually, then add, then commit.
• Show merge logs:

git log --graph --pretty=oneline --abbrev-commit
git log --graph

stash to save current work

git stash # save the work
git stash list # list saved works
git stash pop # restore the saved works and delete the stash

cherry-pick to copy a specific commit

git cherry-pick <commit id>

Cooperation

• 从本地推送分支，使用git push origin branch-name，如果推送失败，先用git pull抓取远程的新提交；
• 在本地创建和远程分支对应的分支，使用git checkout -b branch-name origin/branch-name，本地和远程分支的名称最好一致；
• 建立本地分支和远程分支的关联，使用git branch --set-upstream branch-name origin/branch-name；
• 从远程抓取分支，使用git pull，如果有冲突，要先处理冲突。

Tag is a name that we give to a commit.

• Set a new tag to the newest commit:

git tag <name>
# add message:
git tag -a v0.1 -m "version 0.1 released"

To a past commit?

git tag <name> <commit id>

• List all tag:

git tag

Show info of a tag:

git show <tagname>

• Delete a tag:

git tag -d <name>