Github Cheatsheet

Github Cheatsheet

GitHub is a powerful platform for version control, collaboration, CI/CD automation, and DevOps workflows. This cheatsheet provides an in-depth guide to using GitHub, covering basic operations to advanced features.

1. Introduction to GitHub

What is GitHub?

GitHub is a web-based platform that uses Git for version control and provides tools for:

• Collaborative software development
• CI/CD automation
• Project management
• Code review and DevOps integration

Key Features

• Git Repositories: Centralized code hosting with Git.
• Collaboration: Pull requests, code reviews, and discussions.
• Actions: Automate workflows with GitHub Actions.
• Project Management: Boards, issues, and milestones for agile workflows.
• Security: Dependabot alerts and code scanning for vulnerabilities.

2. Getting Started

Creating an Account

1. Sign up at GitHub.
2. Create or join an organization for team collaboration.

Adding SSH Keys

1. Generate an SSH key:

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   ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

2. Add the key to your GitHub account:

   • Go to Settings → SSH and GPG keys → Add Key.

Creating a Repository

1. Go to Repositories → New.
2. Configure repository name, description, and visibility.
3. Add a .gitignore file or license if needed.

3. Basic GitHub Operations

Cloning a Repository

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git clone git@github.com:username/repository.git

Committing and Pushing Changes

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# Stage changes
git add .
# Commit changes
git commit -m "Initial commit"
# Push changes
git push origin main

Pulling Changes

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git pull origin main

4. Branching and Merging

Creating and Switching Branches

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# Create a new branch
git checkout -b feature-branch
# Switch to an existing branch
git checkout main

Pushing a Branch

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git push origin feature-branch

Merging Branches

1. Open a Pull Request on GitHub:
   • Navigate to the repository → Pull Requests → New Pull Request.
2. Review and merge changes.

Deleting a Branch

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# Delete locally
git branch -d feature-branch
# Delete on remote
git push origin --delete feature-branch

5. GitHub Issues and Project Boards

Creating an Issue

1. Go to Issues → New Issue.
2. Add title, description, and assign labels or assignees.

Automating Project Boards

• Add Issues Automatically:
  1. Go to the project board.
  2. Set up automation rules like "Add issues in progress."

Linking Pull Requests to Issues

Use keywords in PR descriptions:

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Fixes #issue_number
Closes #issue_number

6. GitHub Actions (CI/CD)

GitHub Actions is a workflow automation tool for CI/CD.

Basics of .github/workflows/<workflow>.yml

Example Workflow:

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name: CI Pipeline
 
on:
  push:
    branches:
      - main
 
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout Code
        uses: actions/checkout@v3
      - name: Install Dependencies
        run: npm install
      - name: Run Tests
        run: npm test

Workflow Triggers

• push: Runs the workflow when a commit is pushed.
• pull_request: Triggers on pull requests.
• schedule: Triggers on a cron schedule.

Managing Secrets

1. Go to Settings → Secrets and variables → Actions.
2. Add variables like AWS_ACCESS_KEY_ID or DOCKER_PASSWORD.

Example with Secrets

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jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - name: Deploy to AWS
        run: aws s3 sync ./build s3://my-bucket
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}

7. GitHub Packages

Using GitHub as a Docker Registry

1. Authenticate:

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   docker login ghcr.io -u USERNAME -p TOKEN

2. Build and Push:

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   docker build -t ghcr.io/username/image-name:tag .
   docker push ghcr.io/username/image-name:tag

Installing from GitHub Packages

• Add dependency in package.json (Node.js):

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  "dependencies": {
    "package-name": "github:username/repository"
  }

8. Advanced GitHub Features

Protecting Branches

1. Go to Settings → Branches.
2. Enable branch protection rules (e.g., prevent force-pushes, require PR reviews).

Code Review Automation

• Use GitHub Apps like CodeCov or LGTM for automated code review.

Dependency Management with Dependabot

1. Enable Dependabot under Insights → Dependency Graph.
2. Dependabot creates pull requests to update outdated dependencies.

9. GitHub Security

Code Scanning

1. Enable Code Scanning Alerts under Security.

2. Include scanning actions in workflows:

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   - name: CodeQL Analysis
     uses: github/codeql-action/analyze@v2

Secret Scanning

• GitHub scans public repositories for leaked secrets and alerts the repository owner.

Enabling 2FA

1. Go to Settings → Account Security → Enable Two-Factor Authentication.

10. GitHub CLI (gh)

Installing GitHub CLI

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brew install gh  # macOS
sudo apt install gh  # Linux

Authenticating

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gh auth login

Common Commands

• Clone a Repository:

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  gh repo clone username/repository

• Create a Pull Request:

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  gh pr create --title "Feature Update" --body "Details of PR"

• List Issues:

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  gh issue list

11. GitHub API

Using the API

Authenticate using a personal access token:

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curl -H "Authorization: token YOUR_TOKEN" https://api.github.com/user/repos

Example: Creating an Issue

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curl -X POST -H "Authorization: token YOUR_TOKEN" \
-H "Content-Type: application/json" \
-d '{"title": "Bug Report", "body": "Description of the bug"}' \
https://api.github.com/repos/username/repository/issues

12. GitHub Best Practices

• Use Descriptive Commit Messages:

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  Fix bug in login page #123

• Enable Branch Protections to enforce review processes.

• Automate Testing using GitHub Actions for pull requests.

• Use Issues and Labels for effective project tracking.

References and Resources

1. GitHub Documentation
2. GitHub CLI Documentation
3. GitHub Actions Guide

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