Version Control

What is Version Control?

Version Control (also known as source control) is a system that records changes to files over time, allowing you to recall specific versions later.

Git Basics

# Initialize repository
git init

# Clone repository
git clone https://github.com/user/repo.git

# Check status
git status

# Add files
git add .
git add file.js

# Commit changes
git commit -m "Add new feature"

# Push to remote
git push origin main

# Pull latest changes
git pull origin main

Branching Strategy

Git Flow

# Main branches
main (production)
develop (integration)

# Supporting branches
feature/user-authentication
hotfix/critical-bug
release/v1.2.0

# Create feature branch
git checkout -b feature/user-auth develop

# Work on feature
git add .
git commit -m "Implement user authentication"

# Merge to develop
git checkout develop
git merge feature/user-auth

# Delete feature branch
git branch -d feature/user-auth

Trunk-Based Development

# Single main branch
main

# Short-lived feature branches
git checkout -b feature/quick-fix
# Work for < 1 day
git push origin feature/quick-fix
# Create PR and merge quickly

Multi-Stack Examples

Angular Project

# .gitignore for Angular
node_modules/
dist/
.angular/
*.log
.env

# Commit Angular changes
git add src/app/
git commit -m "feat: add user dashboard component"
git push origin feature/dashboard

.NET Project

# .gitignore for .NET
bin/
obj/
*.user
*.suo
appsettings.Development.json

# Commit .NET changes
git add Controllers/
git commit -m "feat: add user controller"
git push origin feature/user-api

Node.js Project

# .gitignore for Node.js
node_modules/
.env
*.log
dist/

# Commit Node.js changes
git add src/
git commit -m "feat: add authentication middleware"
git push origin feature/auth

Commit Messages

Conventional Commits

# Format: <type>(<scope>): <subject>

# Types
feat: New feature
fix: Bug fix
docs: Documentation
style: Formatting
refactor: Code restructuring
test: Adding tests
chore: Maintenance

# Examples
git commit -m "feat(auth): add JWT authentication"
git commit -m "fix(api): resolve null pointer exception"
git commit -m "docs(readme): update installation steps"
git commit -m "test(user): add unit tests for user service"

Pull Requests

# .github/pull_request_template.md
## Description
Brief description of changes

## Type of Change
- [ ] Bug fix
- [ ] New feature
- [ ] Breaking change
- [ ] Documentation update

## Testing
- [ ] Unit tests pass
- [ ] Integration tests pass
- [ ] Manual testing completed

## Checklist
- [ ] Code follows style guidelines
- [ ] Self-review completed
- [ ] Comments added for complex code
- [ ] Documentation updated

Code Review

# Review process
1. Create feature branch
2. Make changes
3. Push to remote
4. Create pull request
5. Code review
6. Address feedback
7. Approve and merge

# GitHub CLI for reviews
gh pr create --title "Add user authentication"
gh pr review --approve
gh pr merge

Merge Strategies

Merge Commit

git checkout main
git merge feature/new-feature
# Creates merge commit

Squash and Merge

git checkout main
git merge --squash feature/new-feature
git commit -m "feat: add new feature"
# Combines all commits into one

Rebase and Merge

git checkout feature/new-feature
git rebase main
git checkout main
git merge feature/new-feature
# Linear history

Tagging Releases

# Create tag
git tag -a v1.0.0 -m "Release version 1.0.0"

# Push tags
git push origin v1.0.0
git push origin --tags

# List tags
git tag -l

# Checkout tag
git checkout v1.0.0

Handling Conflicts

# When merge conflict occurs
git pull origin main
# CONFLICT in file.js

# Edit file.js to resolve conflicts
<<<<<<< HEAD
const version = '1.0.0';
=======
const version = '2.0.0';
>>>>>>> feature/update-version

# Resolve to:
const version = '2.0.0';

# Mark as resolved
git add file.js
git commit -m "resolve: merge conflict in version"

Git Hooks

# .git/hooks/pre-commit
#!/bin/sh
npm run lint
npm test

# Make executable
chmod +x .git/hooks/pre-commit

# Using Husky
npm install husky --save-dev
npx husky install

# .husky/pre-commit
#!/bin/sh
npm run lint
npm test

Monorepo Management

# Structure
project/
├── apps/
│   ├── angular-app/
│   ├── api/
│   └── admin/
├── libs/
│   ├── shared/
│   └── ui/
└── package.json

# Commit specific app
git add apps/angular-app/
git commit -m "feat(angular): add dashboard"

# Commit shared library
git add libs/shared/
git commit -m "feat(shared): add validation utils"

Best Practices

1. Commit often: Small, focused commits
2. Write clear messages: Descriptive commit messages
3. Use branches: Feature branches for development
4. Review code: Pull request reviews
5. Keep history clean: Rebase or squash when appropriate
6. Tag releases: Version your releases
7. Protect main: Branch protection rules
8. Use .gitignore: Exclude unnecessary files

Interview Tips

• Explain version control: Track changes over time
• Show Git commands: Basic workflow
• Demonstrate branching: Git Flow, trunk-based
• Discuss commits: Conventional commits format
• Mention strategies: Merge, squash, rebase
• Show multi-stack: Angular, .NET, Node.js examples

Summary

Version Control tracks code changes over time using systems like Git. Use branching strategies like Git Flow or trunk-based development. Write clear commit messages following conventions. Use pull requests for code review. Apply appropriate merge strategies. Tag releases for versioning. Essential foundation for CI/CD and team collaboration.