GITHUB / LESSON 06

Branches.

Working on features in isolation

Written by Andrew Lee JenkinsPublished Oct 5, 202612 min readFree lesson

So far you've been working on one single version of your project. Which is fine... right up until you want to try something new and you're nervous about wrecking the code that already works. That's EXACTLY what branches are for.

What is a Branch?

A branch is basically a copy of your project where you can mess around freely. Your original stays safe the whole time you're trying new things.

Picture yourself writing an essay.

You've got your main essay (the "main" branch)
You want to try out a different introduction
So you make a copy to experiment on
If you like it, you keep it, and if you hate it, you toss it
Your original essay was never in any danger

The Main Branch

Every repository has a default branch, usually called main (older repositories might call it master). This is treated as the "official" version of your project.

The rule. Keep main working at ALL times. Never push broken code directly to main. My dad's rule was "do it right or don't do it at all," and main is where that rule lives.

Creating a Branch

Alright, let's make a new branch and try something out.

Step 1. Make Sure You're in Your Repo

Example

cd ~/Projects/my-first-repo

Step 2. See Your Current Branch

Example

git branch

You'll see * main. That lil star shows which branch you're on.

Step 3. Create a New Branch

Example

git checkout -b add-feature

This creates a new branch called add-feature and switches you over to it in one move.

Branch naming tips.

Keep it lowercase
Use hyphens instead of spaces
Be descriptive, like fix-login-bug, add-contact-page or update-styles (future you will be grateful)

Step 4. Verify You're on the New Branch

Example

git branch

Now you'll see this.

Example

  main
* add-feature

The star moved to add-feature. You're in.

Working on Your Branch

From here on, any changes you make land on the add-feature branch. Your main branch stays exactly how you left it.

Step 5. Make a Change

Example

echo "This is a new feature" > feature.txt

Step 6. Add and Commit

Example

git add feature.txt
git commit -m "Add feature file"

Your change is saved on the add-feature branch. Over on main, that file doesn't exist at all.

Switching Between Branches

You can hop back to main whenever you want.

Example

git checkout main

Now look at your files. feature.txt is GONE! Don't panic... it still exists on the add-feature branch.

Switch back.

Example

git checkout add-feature

Aaand feature.txt is back. Each branch keeps its own version of your project.

Pushing a Branch to GitHub

Right now your new branch only exists on your computer. To save it to GitHub, run this.

Example

git push -u origin add-feature

The -u origin add-feature part tells Git to create this branch on GitHub and hook it up to your local branch. After that first push, plain old git push does the job.

Merging Branches

Happy with your changes? Then it's time to merge them back into main.

Step 1. Switch to Main

Example

git checkout main

Step 2. Merge Your Branch

Example

git merge add-feature

Git takes the changes from add-feature and combines them into main.

Step 3. Push the Updated Main

Example

git push

Now main has all the changes you made on add-feature. Donezo!

Deleting a Branch

Once it's merged, you might not need that branch hanging around anymore.

Example

git branch -d add-feature

That deletes the branch locally, on your computer. To delete it on GitHub too, run this.

Example

git push origin --delete add-feature

Common Branch Workflow

Here's how branches usually get used, start to finish.

You're on main with working code
You create a branch for a new feature with git checkout -b new-feature
You make your changes and commit them on that branch
You push the branch to GitHub with git push -u origin new-feature
You create a "Pull Request" on GitHub (that's next lesson)
After review, you merge the branch into main
You delete the branch since it's done its job

Example

main:        o---o-----------o-----------o (merged!)---o
                  \                       /
new-feature:       o---o-------o---------+
                   (feature work)

The top row is main and the bottom row is the new-feature branch. It splits off, picks up a few commits, and then merges back into main.

Quick Reference

Screenshot this one. You'll be back.

Command	What It Does
`git branch`	List all branches
`git checkout -b name`	Create and switch to new branch
`git checkout name`	Switch to existing branch
`git merge name`	Merge branch into current branch
`git branch -d name`	Delete a branch
`git push -u origin name`	Push new branch to GitHub

TL;DR

Branches let you build new features without touching main
The main branch should ALWAYS have working code
Create branches with git checkout -b branch-name
Switch between branches with git checkout branch-name
Merging brings changes from one branch into another
Delete branches after you've merged them (only the capital D version can force out an unmerged one)

What's Next?

Merging directly works fine, but on a team you usually want somebody to look over your code first. In the next lesson you'll learn about Pull Requests, which is how you propose changes and get feedback before anything gets merged...

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