Making and Switching Branches

Two commands: one makes a branch and puts you on it, the other moves you between branches that already exist. The surprising part is watching your files change.

Create and switch in one step

git switch -c sightings-page
git branch

  main
* sightings-page

The -c means "create". The new label was made at your current commit, which means both branches currently point at exactly the same place. Nothing has diverged yet.

Committing on a branch

Work as normal — edit, stage, commit. The only thing that changes is which label moves:

git add sightings.js
git commit -m "Add the sightings list script"
git add index.html
git commit -m "Link the sightings list from the home page"

main has not moved. It still points at the commit it pointed at when you branched. The two versions of Sandpiper now genuinely differ, and both exist in the same folder.

Switching back

git switch main

Open index.html now and the sightings link is gone. Look in the folder and sightings.js is not there at all. This is the moment the model becomes real: your folder shows one branch at a time.

Nothing was lost. Switch back and everything returns:

git switch sightings-page

Two commands, two versions of the project, one folder. Practise this a few times on Sandpiper until the disappearing file stops being alarming, because it is the single most common source of "Git deleted my work" panic and it is entirely harmless.

The older spelling

git checkout -b name creates and switches; git checkout name switches. They do the same jobs and appear in every tutorial written before 2019.

switch exists because checkout had accumulated too many unrelated responsibilities — switching branches, restoring files, visiting old commits — and one command doing three different things is how beginners get hurt. This book uses switch; recognize checkout when you meet it in the wild.

When Git refuses to switch

Sometimes the switch does not happen:

error: Your local changes to the following files would be overwritten by checkout:
        index.html
Please commit your changes or stash them before you switch branches.
Aborting

Read it as a sentence. You have uncommitted changes to a file, and the branch you asked for has a different version of that same file. Switching would overwrite your work, so Git stopped.

Two ways forward, both one command. Commit the changes, if they are coherent. Or stash them — the drawer from the last chapter — if they are not. The message even tells you both. This is Git protecting you, and it is the most common branch-related message you will see.