Lesson

Branches

Branches are movable pointers. Learn how switching, diverging, and deleting work.

Beginner 7 min read

Learning objectives

Understand a branch as a pointer to a commit
See how new commits move only the active branch
Recognize diverging history and detached HEAD

A branch is a pointer

Creating a branch writes a new pointer at the current commit. That is the entire cost — no files are copied. This is why Git branches are cheap and encouraged.

Only the active branch moves

When you commit, only the branch HEAD points at advances. Other branches stay where they are, which is how two branches diverge from a common commit.

Detached HEAD

If you check out a commit hash directly, HEAD points at the commit rather than a branch. Commits you make there belong to no branch and can be lost when you switch away.

Try it yourself

interactive visualization

Empty folder

Run git init to create a repository.

Working directory

Clean — no uncommitted changes.

git add ↓

Staging area

Nothing staged. Run git add.

git commit ↓

Repository

No commits yet.

1/6Empty repositoryOpen in visualizer

Branch off, commit on the feature, then switch back — main is unchanged.

Commands used

terminal

git switch -c feature
git add feature.ts
git commit -m "feat"
git switch main
git log --oneline

Common mistakes

• Committing in detached HEAD and losing the work.
• Deleting an unmerged branch with -D.

Best practices

• Use descriptive names: feat/…, fix/…, docs/….
• Keep branches short-lived and focused.

Mini challenge

Create a branch, add a commit, switch back to main, and confirm main did not move.

Open the visualizer to try it

Summary

Branches are cheap movable pointers.
Only the checked-out branch advances on commit.
Detached HEAD commits belong to no branch.

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