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🔧 Git & GitHub Basics

**Essential version control for robotics development** *Learn Git to manage your lab code, collaborate with teammates, and track your progress*

🎯 Overview

Git is a version control system that helps you track changes in your code, collaborate with others, and maintain a history of your work. This guide covers the essential Git commands you'll need for ENME480 labs and projects.

💻 Prerequisites

Before starting, ensure you have: - ✅ Git installed on your system - ✅ GitHub account created - ✅ Basic terminal knowledge

🚀 Getting Started

Install Git

# Ubuntu/Debian
sudo apt install git

# Check installation
git --version

Configure Git

# Set your name and email
git config --global user.name "Your Name"
git config --global user.email "your.email@umd.edu"

# Check configuration
git config --list

📚 Core Git Concepts

Repository (Repo)

  • Local repository: Git repository on your computer
  • Remote repository: Git repository on GitHub/GitLab
  • Clone: Copy remote repository to local machine

Working Directory

  • Working directory: Where you edit files
  • Staging area: Area where changes are prepared for commit
  • Repository: Where committed changes are stored

Basic Workflow

  1. Edit files in working directory
  2. Stage changes to staging area
  3. Commit changes to repository
  4. Push changes to remote repository

🔧 Essential Git Commands

Initializing a Repository

# Create new repository
git init

# Clone existing repository
git clone https://github.com/username/repository.git

# Check repository status
git status

Making Changes

# Stage all changes
git add .

# Stage specific files
git add filename.py
git add *.py

# Check what's staged
git diff --cached

# Commit changes
git commit -m "Add robot control functions"

# Check commit history
git log
git log --oneline

Managing Branches

# List branches
git branch

# Create new branch
git branch feature-name

# Switch to branch
git checkout feature-name

# Create and switch to new branch
git checkout -b feature-name

# Merge branch
git checkout main
git merge feature-name

# Delete branch
git branch -d feature-name

🌐 Working with GitHub

Setting up SSH Keys

# Generate SSH key
ssh-keygen -t ed25519 -C "your.email@umd.edu"

# Start SSH agent
eval "$(ssh-agent -s)"

# Add SSH key
ssh-add ~/.ssh/id_ed25519

# Copy public key to GitHub
cat ~/.ssh/id_ed25519.pub

Remote Operations

# Add remote repository
git remote add origin https://github.com/username/repository.git

# Check remotes
git remote -v

# Push changes
git push origin main

# Pull changes
git pull origin main

# Fetch changes (without merging)
git fetch origin

📝 Common Workflows

Daily Workflow

# Start of day - get latest changes
git pull origin main

# Make changes to files
# ... edit files ...

# Check what changed
git status
git diff

# Stage and commit changes
git add .
git commit -m "Implement joint limit checking"

# Push changes
git push origin main

Feature Development

# Create feature branch
git checkout -b feature/joint-control

# Make changes
# ... implement feature ...

# Commit changes
git add .
git commit -m "Add joint control system"

# Push feature branch
git push origin feature/joint-control

# Create pull request on GitHub
# ... merge on GitHub ...

# Switch back to main
git checkout main
git pull origin main

# Delete feature branch
git branch -d feature/joint-control

🔍 Useful Git Commands

Viewing History

# View commit history
git log --oneline --graph

# View changes in specific commit
git show commit_hash

# View changes in working directory
git diff

# View staged changes
git diff --cached

Managing Files

# Remove file from Git
git rm filename.py

# Rename file
git mv oldname.py newname.py

# Ignore files
echo "*.log" >> .gitignore
echo "build/" >> .gitignore

Undoing Changes

# Undo last commit (keep changes)
git reset --soft HEAD~1

# Undo last commit (discard changes)
git reset --hard HEAD~1

# Undo changes in working directory
git checkout -- filename.py

# Revert specific commit
git revert commit_hash

📱 GitHub Desktop (Optional)

Why Use GitHub Desktop?

  • Visual interface for Git operations
  • Easier for beginners than command line
  • Built-in merge conflict resolution
  • Good for simple workflows

Installation

# Download from GitHub
# https://desktop.github.com/

# Install and authenticate with your GitHub account

🧪 Practice Exercises

Exercise 1: Create a Lab Repository

# Create directory for lab work
mkdir enme480-labs
cd enme480-labs

# Initialize Git repository
git init

# Create README file
echo "# ENME480 Lab Work" > README.md

# Make first commit
git add README.md
git commit -m "Initial commit: Add README"

# Create GitHub repository and push
git remote add origin https://github.com/username/enme480-labs.git
git push -u origin main

Exercise 2: Work with Branches

# Create feature branch
git checkout -b lab/week1

# Create lab file
echo "# Week 1 Lab" > week1.md

# Commit changes
git add week1.md
git commit -m "Add Week 1 lab notes"

# Push feature branch
git push origin lab/week1

# Switch back to main
git checkout main

# Merge feature branch
git merge lab/week1

# Push merged changes
git push origin main

🔧 Troubleshooting Common Issues

Merge Conflicts

# When you get a merge conflict
git status  # See conflicted files

# Edit conflicted files to resolve conflicts
# Look for <<<<<<<, =======, >>>>>>> markers

# After resolving conflicts
git add .
git commit -m "Resolve merge conflicts"

Authentication Issues

# If you get authentication errors
git config --global credential.helper store

# Or use personal access token
# Generate token on GitHub: Settings → Developer settings → Personal access tokens

Large Files

# If you accidentally commit large files
git filter-branch --tree-filter 'rm -f large_file.dat' HEAD

# Or use Git LFS for large files
git lfs install
git lfs track "*.dat"

📚 Git Best Practices

Commit Messages

  • Use present tense: "Add feature" not "Added feature"
  • Be descriptive: "Implement joint limit checking" not "Fix bug"
  • Keep it short: First line under 50 characters
  • Use imperative mood: "Add", "Fix", "Update", "Remove"

Branch Naming

  • Feature branches: feature/description
  • Bug fixes: fix/description
  • Lab work: lab/week1, lab/week2
  • Project work: project/final-project

When to Commit

  • After completing a logical unit of work
  • Before making major changes to working code
  • After fixing a bug or implementing a feature
  • At the end of each lab session

🆘 Getting Help

Git Resources

Course Support

  • Piazza: Ask questions on course forum
  • Office Hours: Get help from TA or instructor
  • Lab Sessions: Hands-on help during labs

🚀 Next Steps

After mastering Git basics:

  1. Set up your lab repository on GitHub
  2. Practice with daily commits during lab work
  3. Collaborate with teammates on group projects
  4. Learn advanced Git features as needed
**Ready to manage your code? Let's set up your lab repository! 📚** [🐧 Ubuntu Setup](ubuntu-setup.md){ .md-button } [🤖 ROS Setup](ros-setup.md){ .md-button } [📚 Back to Resources](resources.md){ .md-button }

Last updated: Fall 2025 • Back to Resources