Git Commands

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This is a basic Git tutorial.

Introduction

This post will list some frequently used commands. My operating system is Ubuntu 24.04.02.🧐

Repository

Repository includes all the projects, you need to create a folder to create a repository.
I will create a folder called “git_test”

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mkdir git_test
cd git_test
git init

I have a file named “test.c” in this folder, enter git add test.c to place the file into Git’s staging area.
If you have other files, and you want to put all these files into the Git staging area at once, enter git add .
If you have finished modifying all the files and have put them into Git’s staging area, enter git commit -m "...Your commit message..."

git commit

You can view previous commit records by typing git log
git_log
If you want to revert to a previous version, enter git reset --hard <Version>
<Version> can be a commit hash (e.g., d118c) or a relative reference (e.g., HEAD^).

There are two ways to specify the version in <Version>

  1. Relative addressing
    The current version is represented by HEAD. If you want to go to the previous version, enter HEAD^.The version before last is HEAD^^. The 10th previous version is HEAD~10.

  2. ID addressing

    If you want to go to the “second version” in the image, enter d118or d118c, at least four characters and ensure there is no ambiguity.

git reset --hard d118 or git reset --hard HEAD^

Now we are at “second commit”, type git log.
git_log2
At this point, we find that we cannot view the ID of “third commit”. If you want go to “third commit” but don’t know its ID, type git reflog
git_reflog
Enter git reset --hard e398
Now you have entered “third commit”.

Branch

Use git branch to view all branches.
Use git checkout master to switch to the “master” branch.
Use git branch name to create a new branch called “name”, but the HEAD pointer will not move to name.
Use git checkout -b name2 to create a new branch and point HEAD to name2.
Merge the name2 branch into the master branch and delete name2 :

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git checkout master
git merge name2
git branch -d name2

Remote Git repository

I will take GitHub as an example. And I will name this remote repository “git_test”.

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git remote add git_test git@github.com:username/your_repo.git
git push git_test master

If you haven’t configured the SSH key for the current machine on GitHub before, follow these steps:

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ssh-keygen -t ed25519 -C "your_github_email@email.com"
cat ~/.ssh/id_ed25519.pub

Copy the displayed key. Open Github, go to settings —>SSH and GPG keys —>New SSH key.
Give it a name and paste the key.

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ssh -T git@github.com

If a Hi <username>! You've successfully authenticated, but GitHub does not provide shell access. prompt appears, it means you have successfully configured it.🤓

If ssh: connect to host github.com port 22: Connection refused appears, it means that port 22 cannot connect normally😭. Don’t worry, we can use GitHub’s alternative SSH port 443.🧐

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nano ~/.ssh/config

Copy the following content:

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Host github.com
  HostName ssh.github.com
  Port 443
  User git
  • Press Ctrl+Shift+V to paste.
  • Press Ctrl+O to save, then Enter to confirm.
  • Press Ctrl+X to exit.
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ssh -T git@github.com
yes

Then Hi <username>! You've successfully authenticated, but GitHub does not provide shell access. will appear.😊

Try git push git_test master again.
git_success
Congratulations!✌️

Further learning📚

  1. https://docs.net9.org/basic/git/.
  2. https://blog.csdn.net/qcwl66/article/details/144968361
  3. https://zhuanlan.zhihu.com/p/1910420791494972983