Step 2 — Your first Git commit

"Roll back to last month", "collaborate with a friend", and "keep my code safe" — one tool solves all three.

1. What Git stores

Snapshots of the folder at each point in time. One commit = one snapshot.

t0: README.md "hi"
t1: README.md "hi world"       ← commit 1
t2: README.md "hi world!"      ← commit 2

Each commit references the previous by hash, forming a chain.

2. Install

# Windows
winget install Git.Git

# macOS
brew install git

# Linux
sudo apt install git

git --version    # 2.40+

3. One-time config

git config --global user.name "Your Name"
git config --global user.email "you@example.com"
git config --global init.defaultBranch main
git config --global core.autocrlf input    # (Windows) line endings

Use a real email — commits are tagged with it.

4. First repo

mkdir my-first-repo
cd my-first-repo
git init

A hidden .git/ folder now tracks history.

5. Three areas

Working tree  →  Staging  →  Repository
 editing           add          commit

• Edit — Git only notices changes
• add — stage for next commit
• commit — snapshot sealed

echo "# My project" > README.md
git status
git add README.md
git status
git commit -m "docs: first README"
git log

6. Ten basic commands

git status
git diff
git diff --staged
git add .
git commit -m "msg"
git log --oneline
git log --graph --oneline
git branch
git checkout -b feature-x
git merge feature-x

7. Branches — parallel worlds

git checkout -b fix-login
# edit
git add . && git commit -m "fix: login"
git checkout main
git merge fix-login

A branch = another line of snapshots diverging from a point on main.

8. Connect to GitHub

Create an empty repo on GitHub, then:

git remote add origin https://github.com/you/repo.git
git push -u origin main

Subsequent pushes just use git push.

9. Collaboration cycle

git pull
git checkout -b fix-x
# work
git add . && git commit -m "fix: x"
git push -u origin fix-x
# Open a Pull Request on GitHub

10. Commit messages

Subject line + blank + body.

feat: add signup page

- email / password inputs
- POST to /api/signup
- handle loading and errors

Common tags: feat, fix, docs, refactor, test, chore.

11. Undoing

git commit --amend -m "new msg"
git restore --staged file
git restore file                    # discard edits (careful)
git reset HEAD~1                    # undo last commit, keep edits

Avoid reset --hard as a beginner.

12. .gitignore

node_modules/
.next/
.env
.env.local
*.log
dist/
.DS_Store

Never commit .env — rotate secrets if you do.

13. Gotchas

• Accidentally committing .env — rotate secrets, history is hard to scrub
• HTTPS push requires a PAT (or use SSH keys)
• Merge conflicts — resolve manually, then git add + commit
• Lost state — git reflog shows every HEAD move; usually recoverable

Closing

Ten commands cover 80% of real work. Learn the rest as you need it. Make git status a reflex.

Next

• 03-vscode

References: Pro Git Book (free) · GitHub Skills · Oh Shit, Git!?!.