Lesson 1: The Parallel Universe

Imagine you could create a parallel universe where you experiment freely — and if the experiment succeeds, merge it back into reality. If it fails, just delete that universe. No consequences. That's what branches do in Git.

What is a Branch?

A branch is a separate line of development. It's a copy of your project where you can make changes without affecting the main branch.

main:     A ── B ── C
                     \
feature:              D ── E ── F

• main stays stable while feature evolves independently.
• When the feature is ready, you merge it back.

Why Branches Matter in DevOps

• Feature branches — Each new feature gets its own branch.
• Hotfix branches — Emergency fixes without disrupting development.
• Release branches — Prepare a release while development continues.
• Environment branches — staging, production reflect deployed states.

Creating a Branch

git branch feature/login        # Create a new branch
git checkout feature/login      # Switch to it

Or the shortcut:

git checkout -b feature/login   # Create AND switch in one command

Switching Branches

git checkout main               # Switch back to main
git switch feature/login        # Modern alternative to checkout

Listing Branches

git branch                      # Local branches
git branch -a                   # All branches (including remote)
git branch -v                   # Branches with last commit info

Branch Naming Conventions

| Pattern | Example | Use Case | |---------|---------|----------| | feature/ | feature/user-auth | New features | | bugfix/ | bugfix/login-crash | Bug fixes | | hotfix/ | hotfix/security-patch | Urgent production fixes | | release/ | release/v2.0 | Release preparation |

Mission Objective

Create your first parallel universe:

1. Create it: Run git branch feature/login to create a new branch.
2. Enter it: Switch to it with git checkout feature/login.
3. Survey: Run git branch -a to see all branches.

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