Introduction to Git and GitHub

Learn version control with Git and collaborate with GitHub - essential skills for modern software development and data science.

What is Git?

Git is a distributed version control system that tracks changes in your code over time. It allows you to:

• Save snapshots of your project at different points in time
• Collaborate with others without overwriting each other's work
• Experiment with new features without breaking working code
• Revert to previous versions when things go wrong
• Track who made what changes and when

What is GitHub?

GitHub is a cloud-based hosting service for Git repositories. It provides:

• Remote storage for your Git repositories
• Collaboration tools (pull requests, issues, discussions)
• Code review features
• Project management tools
• CI/CD integration
• Portfolio for showcasing your work

Why Learn Git?

For Data Scientists

• Track changes to data analysis notebooks
• Collaborate on machine learning projects
• Version datasets and model configurations
• Share reproducible research
• Manage experiment tracking

For Developers

• Industry standard for version control
• Required for most tech jobs
• Essential for open-source contribution
• Enables team collaboration
• Facilitates code review processes

Key Concepts

Repository (Repo)

A folder that Git tracks. Contains all your project files and the complete history of changes.

Commit

A snapshot of your project at a specific point in time. Like saving your game progress.

Branch

An independent line of development. Allows you to work on features without affecting the main code.

Remote

A version of your repository hosted on the internet (usually on GitHub).

Clone

Creating a local copy of a remote repository on your computer.

Push

Uploading your local commits to a remote repository.

Pull

Downloading changes from a remote repository to your local machine.

Git vs GitHub

Installing Git

Windows

1. Download from git-scm.com
2. Run the installer
3. Use default settings (or customize as needed)
4. Verify: Open Git Bash and run git --version

macOS

# Using Homebrew
brew install git

# Or download from git-scm.com

Verify installation:

git --version

Linux (Ubuntu/Debian)

sudo apt-get update
sudo apt-get install git

Verify installation:

git --version

Initial Git Configuration

After installing Git, configure your identity:

# Set your name
git config --global user.name "Your Name"

# Set your email
git config --global user.email "your.email@example.com"

# Check your configuration
git config --list

Creating a GitHub Account

1. Go to github.com
2. Click "Sign up"
3. Follow the registration process
4. Verify your email address
5. Complete your profile

Basic Workflow Overview

Here's a typical Git workflow:

1. Initialize or clone a repository
   ↓
2. Make changes to files
   ↓
3. Stage changes (git add)
   ↓
4. Commit changes (git commit)
   ↓
5. Push to remote (git push)
   ↓
6. Repeat steps 2-5

Your First Git Repository

Let's create your first Git repository:

# Create a new folder
mkdir my-first-repo
cd my-first-repo

# Initialize Git
git init

# Check status
git status

You should see:

Initialized empty Git repository in /path/to/my-first-repo/.git/

Creating Your First Commit

# Create a file
echo "# My First Repo" > README.md

# Check status
git status

# Stage the file
git add README.md

# Commit
git commit -m "Initial commit: Add README"

# View commit history
git log

Common Git Terms Explained

Working Directory

The folder on your computer where you're currently working. Contains your actual files.

Staging Area (Index)

A intermediate area where you prepare files before committing. Think of it as a "preview" of your next commit.

Local Repository

The .git folder in your project that stores all commits and history on your computer.

Remote Repository

A version of your project hosted on a server (like GitHub).

HEAD

A pointer to your current branch and commit. Think of it as "you are here."

Git Workflow Diagram

Working Directory  →  Staging Area  →  Local Repository  →  Remote Repository
                   git add          git commit          git push

                   ←                 ←                   ←
                   git restore      git reset           git pull

Best Practices

1. Commit Often - Make small, focused commits
2. Write Clear Messages - Explain what and why, not how
3. Pull Before Push - Always sync before sharing your changes
4. Use Branches - Don't work directly on main/master
5. Review Changes - Check git status and git diff before committing
6. .gitignore - Don't commit sensitive data or generated files

What Not to Commit

Never commit: - Passwords or API keys - Large binary files (use Git LFS instead) - Dependencies (node_modules, venv, etc.) - Personal configuration files - Temporary files - Compiled code (unless necessary)

Create a .gitignore file to exclude these automatically.

Getting Help

# General help
git help

# Help for a specific command
git help commit
git commit --help

# Quick reference
git <command> -h

Resources

• Official Git Documentation
• GitHub Guides
• Pro Git Book (Free online)
• Git Cheat Sheet

What's Next?

In the following tutorials, you'll learn:

1. Basic Git Commands - add, commit, status, log
2. Branching and Merging - Create and manage branches
3. GitHub Basics - Push, pull, clone, fork
4. Collaboration - Pull requests, code review
5. Advanced Topics - Rebase, cherry-pick, stash

Next Tutorial: Basic Git Commands