Cloning and Forking

There are two ways to get a copy of a repository: cloning (for your own repos or to work locally) and forking (to contribute to others' repos).

Cloning Repositories

Cloning creates a local copy of a remote repository.

Basic Clone

# HTTPS
git clone https://github.com/owner/repository.git

# SSH (recommended)
git clone git@github.com:owner/repository.git

# GitHub CLI
gh repo clone owner/repository

What Clone Does

1. Creates a directory named after the repo
2. Downloads all files and history
3. Sets up origin remote pointing to the source
4. Checks out the default branch

Clone Options

# Clone to specific folder
git clone https://github.com/owner/repo.git my-folder

# Clone specific branch
git clone -b develop https://github.com/owner/repo.git

# Shallow clone (only recent history)
git clone --depth 1 https://github.com/owner/repo.git

# Clone with submodules
git clone --recursive https://github.com/owner/repo.git

After Cloning

cd repository

# See the remote
git remote -v
# origin  https://github.com/owner/repository.git (fetch)
# origin  https://github.com/owner/repository.git (push)

# See branches
git branch -a

# Start working
git checkout -b my-feature

Forking Repositories

A fork is your personal copy of someone else's repository on GitHub.

Why Fork?

Use Case	Description
Contributing	Make changes to propose back
Experimentation	Try ideas without affecting original
Starting point	Use as base for your own project
Archiving	Keep a copy of important code

How to Fork

1. Go to the repository on GitHub
2. Click the Fork button
3. Choose where to fork (your account or organization)
4. Wait for GitHub to copy the repo

Fork vs Clone

Fork	Clone
Creates copy on GitHub	Creates copy on your computer
Lives in the cloud	Lives locally
Linked to original	Just downloads files
For contributing	For local work

Typical workflow: Fork on GitHub, then clone your fork locally.

The Fork Workflow

Step 1: Fork on GitHub

Click "Fork" on the original repository.

Step 2: Clone Your Fork

git clone git@github.com:your-username/repository.git
cd repository

Step 3: Add Upstream Remote

git remote add upstream https://github.com/original-owner/repository.git

git remote -v
# origin    git@github.com:your-username/repository.git (fetch)
# origin    git@github.com:your-username/repository.git (push)
# upstream  https://github.com/original-owner/repository.git (fetch)
# upstream  https://github.com/original-owner/repository.git (push)

Step 4: Keep Your Fork Updated

# Fetch updates from original
git fetch upstream

# Merge into your main branch
git checkout main
git merge upstream/main

# Push to your fork
git push origin main

Step 5: Make Changes

# Create feature branch
git checkout -b fix-typo

# Make changes
# ...

# Push to your fork
git push -u origin fix-typo

Step 6: Create Pull Request

On GitHub, create a PR from your fork's branch to the original repository.

Syncing a Fork

Via Command Line

# Fetch upstream changes
git fetch upstream

# Merge into your branch
git checkout main
git merge upstream/main

# Push to your fork
git push origin main

Via GitHub UI

1. Go to your fork on GitHub
2. Click "Sync fork" button
3. Click "Update branch"

Handling Sync Conflicts

If your fork has diverged:

# Fetch upstream
git fetch upstream

# Rebase your changes on top of upstream
git checkout main
git rebase upstream/main

# Force push (your fork only!)
git push --force origin main

When to Clone vs Fork

Clone When

• It's your own repository
• You have direct push access
• You just want a local copy to browse
• You're working on a private team project

Fork When

• You want to contribute to someone else's project
• You don't have push access
• You want your own copy to modify
• You want to propose changes via pull request

GitHub CLI for Cloning and Forking

# Clone a repository
gh repo clone owner/repo

# Fork and clone in one step
gh repo fork owner/repo --clone

# Fork without cloning
gh repo fork owner/repo

# Clone your own repo
gh repo clone my-repo

Submodules

Some repositories contain other repositories:

# Clone with submodules
git clone --recursive https://github.com/owner/repo.git

# Initialize submodules after clone
git submodule init
git submodule update

# Update submodules
git submodule update --remote

Large Repositories

For very large repositories:

# Shallow clone (faster, less history)
git clone --depth 1 https://github.com/owner/large-repo.git

# Later, get more history if needed
git fetch --unshallow

# Partial clone (Git 2.22+)
git clone --filter=blob:none https://github.com/owner/large-repo.git

Troubleshooting

Authentication Issues

# If HTTPS prompts for password, use token
git clone https://token@github.com/owner/repo.git

# Or switch to SSH
git remote set-url origin git@github.com:owner/repo.git

Permission Denied

• Check SSH key is added to GitHub
• Verify repository access permissions
• Use HTTPS with personal access token

Slow Clone

• Use shallow clone: --depth 1
• Clone specific branch only
• Check network connection

Summary

• Clone: Creates local copy for working on
• Fork: Creates GitHub copy for contributing
• Use SSH for passwordless authentication
• Add upstream remote to track original repo
• Keep forks synced with upstream
• Use shallow clones for faster downloads
• The fork workflow is essential for open source contribution

In the next lesson, we'll learn how to set up your GitHub profile.