Practice¶

This section contains step-by-step exercises. Each one is self-contained: you can follow them in order or jump to whichever interests you.

Before starting

Make sure you have Git installed and configured as we saw in Workspace, and the SSH connection with GitHub ready per SSH Connection.

Exercise 1 · First commit¶

Goal: create a local repository, make a change, and confirm it. Estimated time: 10 minutes.

Step 1 · Create the folder¶

mkdir my-first-repo
cd my-first-repo

Step 2 · Initialize Git¶

git init

You should see:

Initialized empty Git repository in /path/to/my-first-repo/.git/

Step 3 · Configure the default branch (optional)¶

If you haven't configured init.defaultBranch=main globally yet:

git checkout -b main

Step 4 · Create a file¶

echo "# My first repo" > README.md

Step 5 · Check the status¶

git status

You'll see:

On branch main

No commits yet

Untracked files:
  (use "git add <file>..." to include in what will be committed)
        README.md

nothing added to commit but untracked files present (use "git add" to track)

Step 6 · Add to staging¶

git add README.md
git status

Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
        new file:   README.md

Step 7 · Make the first commit¶

git commit -m ":sparkles: Create initial README"

Expected result

[main (root-commit) abc1234] :sparkles: Create initial README
 1 file changed, 1 insertion(+)
 create mode 100644 README.md

Step 8 · See the history¶

git log --oneline

You'll see your first commit with its short hash.

Exercise 2 · Resolve a conflict¶

Goal: simulate a merge conflict and resolve it manually. Estimated time: 15 minutes.

Step 1 · Prepare the repository¶

mkdir conflict-demo && cd conflict-demo
git init && git checkout -b main
echo "Line 1" > greeting.txt
echo "Line 2" >> greeting.txt
git add greeting.txt
git commit -m ":sparkles: Initial version of greeting"

Step 2 · Create a branch with a change¶

git switch -c feature/greeting
echo "Hello, world!" > greeting.txt
git commit -am ":sparkles: Greeting in English"

Step 3 · Go back to main and make a different change¶

git switch main
echo "Hola, mundo!" > greeting.txt
git commit -am ":sparkles: Greeting in Spanish"

Step 4 · Try the merge¶

git merge feature/greeting

Git can't decide which version of the file to keep:

Auto-merging greeting.txt
CONFLICT (content): Merge conflict in greeting.txt
Automatic merge failed; fix conflicts and then commit the result.

Step 5 · Inspect the conflict¶

cat greeting.txt

You'll see the markers:

<<<<<<< HEAD
Hola, mundo!
=======
Hello, world!
>>>>>>> feature/greeting

Step 6 · Resolve by hand¶

Edit the file and keep only the version you want:

echo "Hello, world!" > greeting.txt

(In real life, you probably want to keep both lines or choose carefully.)

Step 7 · Confirm the resolution¶

git add greeting.txt
git commit -m ":wrench: Resolve conflict in greeting.txt"

Exercise 3 · Pull Request with code review¶

Goal: simulate a complete collaboration flow on GitHub: create a branch, make a change, open a PR, receive feedback, apply it, and merge. Estimated time: 30 minutes.

Step 1 · Create the repository on GitHub¶

Go to github.com/new.
Name: practice-pr.
Check Add a README file.
Click Create repository.

Step 2 · Clone and create a branch¶

git clone git@github.com:YOUR_USER/practice-pr.git
cd practice-pr
git switch -c docs/add-installation

Step 3 · Make a change¶

Edit README.md and add a section:

## Installation

```bash
npm install my-package
```

(Use triple backticks in the actual file.)

Step 4 · Commit and push¶

git add README.md
git commit -m ":books: Document installation in README"
git push -u origin docs/add-installation

Step 5 · Open the PR¶

Go to the URL GitHub shows after the push.
Click Compare & pull request.
Title: Document installation in README.
Description: explanation of what you added and why.
Mark as Draft.
Click Create pull request.

Step 6 · Receive feedback¶

Imagine a reviewer comments:

"Missing prerequisites (Node.js >= 18)."

Step 7 · Apply the feedback¶

Edit README.md:

## Installation

**Prerequisite**: Node.js 18 or higher.

```bash
npm install my-package
```

Commit and push:

git add README.md
git commit -m ":wrench: Mention Node.js 18+ requirement"
git push

The PR updates automatically with the new commit.

Step 8 · Approve and merge¶

Mark the PR as Ready for review.
Approve (yourself in this exercise).
Squash and merge.
Delete the branch.

Exercise 4 · Configure branch protection¶

Goal: apply protection rules to the main branch from the GitHub UI. Estimated time: 10 minutes.

Only applies to repositories where you're an admin

If it's your personal repo, perfect. If it's an organization's, ask for admin access first.

Step 1 · Go to Settings → Branches¶

github.com/YOUR_USER/practice-pr/settings/branches

The first step is to navigate to the Settings tab of the repository. In the screenshot below, the tab is highlighted in orange at the right of the repo header:

Settings tab in the repository header

Image: Settings tab in a GitHub repository header.

Step 2 · Add a rule for `main`¶

Click Add rule.
Branch name pattern: main.
Enable:
☑ Require a pull request before merging.
☑ Require approvals: 1.
☑ Dismiss stale pull request approvals when new commits are pushed.
☑ Require linear history (no merge commits).
☑ Do not allow force pushes.
☑ Do not allow deletions.
Click Create.

Step 3 · Test that it works¶

git switch main
echo "Direct change" >> README.md
git commit -am "test"
git push

You should receive an error:

remote: error: GH006: Protected branch update failed for refs/heads/main.

That confirms the protection works. To make changes to main now, you have to do them via Pull Request.

Additional resources¶

Git Official Tutorial.
Oh My Git! — game to learn Git visually.
Learn Git Branching — interactive tutorial with visualizations.
GitHub Skills — short official courses.

Next step¶

Go back to Home to review all the material or explore the Glossary.