Git Basics: Your First Repository

# Create a new project directory
mkdir my-first-repo
cd my-first-repo

# Initialize Git — creates a hidden .git folder
git init
# Output: Initialized empty Git repository in .../my-first-repo/.git/

# Check the status of your repo
git status
# Output: On branch main. No commits yet. Nothing to commit.

# Create a file
echo "# My Project" > README.md

# Check status — README.md is "untracked"
git status

# Stage the file
git add README.md
# Or stage ALL changes at once:
git add .

# Check status again — file is now "staged"
git status

# Commit with a message
git commit -m "feat: add README with project description"

# See your commit in the log
git log

# Full log — shows hash, author, date, message
git log

# Compact — one line per commit
git log --oneline

# Compact + visual branch graph
git log --oneline --graph --all

# Show last 5 commits only
git log -5

# Search commits by message
git log --grep="feat"

# Show commits by a specific author
git log --author="Your Name"

# See unstaged changes (Working Directory vs Staging)
git diff

# See staged changes (Staging vs last commit)
git diff --staged

# See changes between two commits
git diff abc1234 def5678

# See changes in a specific file
git diff README.md

# Diff output legend:
# Lines starting with + are ADDED (green)
# Lines starting with - are REMOVED (red)
# Lines with no prefix are unchanged (context)

# Format: type(scope): short description

feat: add user authentication system
feat(auth): add Google OAuth login
fix: resolve null pointer in payment flow
fix(cart): prevent negative quantity bug
docs: update API documentation
chore: upgrade dependencies to latest versions
style: format code with prettier
refactor: extract validation logic into helper
test: add unit tests for UserService
perf: optimize database query with index

# Dependencies
node_modules/
vendor/

# Environment variables (NEVER commit secrets!)
.env
.env.local
.env.production

# Python
__pycache__/
*.pyc
*.pyo
.venv/
venv/

# Build outputs
dist/
build/
*.min.js

# OS files
.DS_Store        # Mac
Thumbs.db        # Windows
desktop.ini

# IDE settings
.vscode/
.idea/
*.swp

# 1. Create and init project
mkdir todo-app && cd todo-app
git init

# 2. Create .gitignore FIRST
echo "node_modules/\n.env\n.DS_Store" > .gitignore
git add .gitignore
git commit -m "chore: add .gitignore"

# 3. Add README
echo "# Todo App\nA simple task manager." > README.md
git add README.md
git commit -m "docs: add README with project overview"

# 4. Create main file
echo "const todos = [];" > app.js
git add app.js
git commit -m "feat: initialize app with empty todos array"

# 5. Add a feature
echo "function addTodo(text) { todos.push({text, done: false}); }" >> app.js
git add app.js
git commit -m "feat: add addTodo function"

# 6. Fix something
# (edit app.js to add validation)
git add app.js
git commit -m "fix: validate empty string in addTodo"

# See your beautiful history!
git log --oneline