Git & GitHub Crash Course 2025 Cheat Sheet

What is Git?

Git is a distributed version control system that allows developers to:

Track changes in code.
Collaborate on projects.
Manage multiple versions of a project.
Work offline with a full local repository.

Basic Git Workflow

Working Directory: Where you make changes to files.
Staging Area: Prepare changes for a commit.
Local Repository: Stores committed changes.
Remote Repository: Backup and share code (e.g., GitHub).

Common Git Commands

Setup

Set username: git config --global user.name "Your Name"
Set email: git config --global user.email "[email protected]"
Default branch to main: git config --global init.defaultBranch main

Initializing & Cloning

Initialize a repository: git init
Clone a repository: git clone <repo_url>

Adding & Committing

Check status: git status
Add files to staging: git add . (or specific file: git add filename)
Commit changes: git commit -m "Commit message"

Working with Remote Repositories

Add a remote: git remote add origin <repo_url>
Push changes: git push -u origin main
Pull changes: git pull origin main

Branching & Merging

Create a branch: git checkout -b branch-name
Switch branches: git checkout branch-name
Merge branch: git merge branch-name
Delete branch:
- Locally: git branch -d branch-name
- Remotely: git push origin --delete branch-name

Logs & History

View commit history: git log
Show specific commit: git show <commit_hash>
Rollback changes:
- Soft reset: git reset <commit_hash> (keeps changes in working directory)
- Hard reset: git reset --hard <commit_hash> (removes changes)

Git Ignore

Use a .gitignore file to exclude files or directories from tracking. Example:

node_modules/
*.log
.env

Working with GitHub

Key Features

Repositories: Host Git repositories online.
Pull Requests: Request to merge changes into the main codebase.
Issues: Track bugs, feature requests, or tasks.
Actions: Automate CI/CD pipelines.

SSH Setup

Generate an SSH key:
```
ssh-keygen -t rsa -b 4096
```
Add the key to your GitHub account.
Test SSH connection:
```
ssh -T [email protected]
```

Pushing Changes

Add a remote:

git remote add origin [email protected]:yourusername/repo.git

Push changes:
```
git push -u origin main
```

Branching Workflow Example

Create a branch:
```
git checkout -b feature/branch-name
```

Make changes and commit:

git add .
git commit -m "Feature: Added functionality"

Push the branch:
```
git push -u origin feature/branch-name
```
Create a pull request on GitHub.
Merge branch into main.

Rollback Example

To undo changes to a specific commit:
```
git reset --hard <commit_hash>
```
Push rollback to remote:
```
git push -f
```

CI/CD with GitHub Actions

Create a .github/workflows directory.

Add a YAML file for automation:

name: Deploy to Vercel
on:
  push:
    branches:
      - main
jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Deploy to Vercel
        run: npx vercel --prod

Tips

Commit Often: Save milestones or completed features.
Use Branches: Isolate features or bug fixes.
Keep Changes Small: Easier to manage and review.

Helpful Resources

Conclusion

Master these basics to use Git and GitHub effectively. Practice regularly, and explore advanced topics like rebasing, stashing, and cherry-picking as you grow.

bradtraversy/git-cheat-sheet.md