Branches — experiment without breaking what works

“I want to redo the design, but I want to keep what I have.” That’s what a branch is for. It splits your work into a separate line so you can try things without breaking the original.

A branch is a line of work

The line you’re on is usually called main. Branch off and you get this:

main       ●──●──●            ← stays in a working state
                └──●──●       ← where you try the new design

Nothing you do on the branch touches main. If it works out, merge it; if it doesn’t, throw the branch away.

Create one and move onto it

Add -c (create) to make a branch and switch to it at once.

git switch -c new-design

You now have a branch called new-design and you’re on it. Confirm with:

git branch

* new-design
  main

The * marks the branch you’re on. Edits you commit now go only onto new-design.

To go back, drop the -c:

git switch main

The moment you switch, the files in your editor change back too. It’s startling the first time, but it’s correct: switching branches tells Git to put the folder into that branch’s state.

Merging: git merge

When the branch work is ready, merge it into main. The key is to move to the receiving side first.

git switch main
git merge new-design

The changes from new-design are now part of main. A branch that has done its job can be deleted:

git branch -d new-design

When you hit a conflict

If the same line changed on both main and your branch, Git can’t choose for you. That’s a conflict.

Open the file and you’ll find markers:

<<<<<<< HEAD
<h1>Shima's page</h1>
=======
<h1>About Shima</h1>
>>>>>>> new-design

• From <<<<<<< HEAD to ======= — the content on your current branch (main)
• From ======= to >>>>>>> — the content on the branch being merged in

What to do is simple: edit it into the form you want and delete the three marker lines.

<h1>About Shima</h1>

Then record it as usual:

git add index.html
git commit -m "Settle the heading wording"

Merging on GitHub: pull requests

On a team, instead of merging locally you push the branch to GitHub and open a pull request — a request to merge.

git push -u origin new-design

After pushing, GitHub shows a “Compare & pull request” button. Opening the request lets others review your changes line by line. Once approved, a button on the page merges it into main.

Even working alone, pull requests are worth practicing: they give you a moment to review your own changes.

When to branch

• For a large rewrite — main stays intact if it goes wrong
• When splitting work with others — you can touch the same files and merge afterwards
• For a small solo fix — working directly on main is fine

“Branch when the change is big” is enough of a rule to start with.

Summary of this lesson

1. A branch is a separate line of work. git switch -c name creates and moves; git switch main returns
2. To merge, move to the receiving branch first, then git merge branch-name
3. A conflict is a question. Edit it into the form you want, then add and commit