How to understand the basic use of git in 20 minutes

This article brings you basic knowledge about the use of git, including basic operations of git, branch operations, change submission operations, etc. I hope it will be helpful to everyone.

#1. Set SSH Key

Set SSH Key so that the device can have permission to access the code warehouse in the account

$ ssh-keygen -t rsa -C "your_email@example.com"

• "your_email@example.com" Set it as the registered email address of your GitHub account
• The id_rsa file is the private key, and id_rsa.pub is the public key.

$ cat ~/.ssh/id_rsa.pub

ssh-rsa The content of the public key your_email@example.com

• Then copy the public key and add it to the account. Pay attention to the # in front. ##ssh-rsa Also copy it
Avatar》Settings》SSH Key》new SSH Key
• 
  

Next verify it, if the word "successfully" appears, it means success

$ ssh -T git@github.com
Enter passphrase for key '/c/Users/MYPC/.ssh/id_rsa':
Hi abc! You've successfully authenticated, but GitHub does not provide shell access.

2. Basic git operations

2.1 git clone existing warehouse

$ git clone git@github.com:hirocastest/Hello-World.git

You will be asked to enter the open key set on GitHub. Password, after successful authentication, the warehouse will be cloned into the current directory.

2.2 git add adds the file to the staging area

After the code is written, add the code to the system's staging area

$ git add 文件夹/文件

2.3 git commit Save the history of the warehouse

The git commit command can actually save the files in the current staging area to the history of the warehouse. Through these records, we can restore files in the working tree.

$ git commit -m "记录一行提交信息"

m indicates an overview of this submission. If you want to record detailed information, remove -m

2.4 After git push

, just Execute the

push command, and the warehouse on GitHub will be updated

$ git push

2.5 git init initializes the warehouse

clone method to create a warehouse, no execution is required init Operation. If you want to set a local file as a warehouse, you need to perform an init operation

$ mkdir git-tutorial

$ cd git-tutorial

$ git init

2.6 git status to view the warehouse status

$ git status
# On branch master
#
# Initial commit
#
nothing to commit (create/copy files and use "git add" to track)

The result is that we are under the master branch and there is nothing to submit Content

2.7 git log View submission log

git log command can view the logs submitted in previous warehouses. Including who made the commit or merge at what time

$ git log
commit 5dbbff6e009abb8a6cc44187c93b694f94fbf82a (HEAD -> main, origin/main, origin/HEAD)
Author: ywm <ywm_up@qq.com>
Date:   Sun Feb 28 17:17:00 2021 +0800

If you only want to display the first line of the commit information, you can add

-- pretty=short after the git log command

$ git log --pretty=short

2.8 git diff Check the difference before and after the change

Execute

git diff Check the difference between the current working book and the staging area

$ git diff

3. Branch operation

You can create multiple branches and perform completely different jobs at the same time. Wait for the branch job to be completed before merging it with the master branch. Through the flexible use of branches, multiple people can perform concurrent development efficiently at the same time.

3.1 git branch displays the branch list

There is an “*” (asterisk) on the left side of the master branch, indicating that this is the branch we are currently on.

$ git branch
* master

3.2 git checkout creates and switches branches

Create and switch to branch feature-A

$ git checkout -b feature-A

In fact, the above command is equivalent to the following two commands

$ git branch feature-A

$ git checkout feature-A

Switch back to branch main

$ git checkout main

Switch back to the previous branch

$ git checkout -

Do this: create a new branch feature, and modify the README on the new branch. md, and add and commit

It can be proved through actual operation that as long as multiple branches are created, multiple functions can be developed at the same time without affecting each other

3.3 git merge merge branches

Add the --no–ff parameter when merging to save the previous branch history

$ git merge --no-ff feature

The editor will then start to enter the merge submission information

3.4 git log --graph View branches as icons

$ git log --graph

4. Change commit operations

4.1 git reset Backtrack historical versions

$ git reset --hard 目标时间点的hash值

View the operation log of the current warehouse through

git reflog to find the hash value before the backtracking history. As long as git's GC (garbage collection) is not performed, the recent historical status can be retrieved at will through the log. Even if the developer performs a git operation by mistake, he can basically use the git reflog command to restore to the original state.

$ git reflog

The most recent operation is printed above, and the oldest operation is printed below.

4.2 Eliminate conflicts

When merging operations, conflicts are prone to occur. At this time, you need to
• open the editor to resolve the conflict
In actual development, one of them often needs to be deleted, so be sure to
• carefully analyze the content of the conflicting part before making modifications.
After resolving the conflict, perform add and commit operations again

If you are not satisfied with the previous submission information, you can use the amend parameter to modify it

$ git commit --amend

4.3 git rebase -i compress history

Before merging branches, if you find some spelling errors in the submitted content, you may wish to submit a modification, and then include the modification into the previous submission and compress it into a history Record.

git rebase -i HEAD~2

You can select the two latest historical records including HEAD in the branch as objects for the period, and open them in the editor

5 推送至远程仓库

5.1 git remote add 添加远程仓库

在创建新仓库的时候，建议不要勾选 README.md 文件，这样会使本地仓库和远程仓库失去整合性。虽然到时候可以强制覆盖，但防止这一情况发生，还是不要勾选，就创建一个空仓库就好。

git remote 在先写代码，后创建仓库的情况下能较好的使用

$ git remote add origin git@github.com:github-book/git-tutorial.git

对于一般先创仓库，后写代码的，需要先 pull 下来仓库，再对文件进行修改

5.2 git push 推送至远程仓库

推送至 master 分支

$ git push -u origin master

-u 参数可以在推送的同时，将 origin 仓库的 master 分支设置为本地仓库当前分支的 upstream（上游），添加这个参数，将来运行 git pull 命令从远程仓库获取内容的时候，本地仓库的这个分支就可以直接从 origin 的 masteer 分支获取内容，省去了另外添加参数的麻烦

除了 master 分支之外，还可以推送到其他分支

$ git checkout -b feature-D

$ git push -u origin feature-D

6 从远程仓库中获取

6.1 git clone 获取远程仓库

$ git clone git仓库地址

将本地的 feature-D 分支更新到最新状态

$ git pull origin feature-D

• 多名开发者在同一个分支中进行作业时，为减少冲突情况的发生，建议更频繁的进行 push 和 pull 操作

推荐学习：《Git教程》

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