Branches

Last updated on 2025-12-03 | Edit this page

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Overview

Questions

  • What are branches?
  • How do I view the current branches?
  • How do I manipulate branches?

Objectives

  • Understand how branches are created.
  • Learn the key commands to view and manipulate branches.

Branching is a feature available in most modern version control systems. Branching in other version control systems can be an expensive operation in both time and disk space. In git, branches are a part of your everyday development process. When you want to add a new feature or fix a bug—no matter how big or how small—you spawn a new branch to encapsulate your changes. This makes it harder for unstable code to get merged into the main code base, and it gives you the chance to clean up your future’s history before merging it into the main branch.

A diagram showing branching in a theoretical git repository.
Git Branching: An example of how branches of a repository are based on each other and evolve over time. (Source: Atlassian Git Tutorial)

The diagram above visualizes a repository with two isolated lines of development, one for a little feature, and one for a longer-running feature. By developing them in branches, it’s not only possible to work on both of them in parallel, but it also keeps the main branch free from questionable code.

The implementation behind Git branches is much more lightweight than other version control system models. Instead of copying files from directory to directory, Git stores a branch as a reference to a commit. In this sense, a branch represents the tip of a series of commits—it’s not a container for commits. The history for a branch is extrapolated through the commit relationships.

()

What is a branch?

In git a branch is effectively a pointer to a snapshot of your changes. It’s important to understand that branches are just pointers to commits. When you create a branch, all Git needs to do is create a new pointer, it doesn’t change the repository in any other way. If you start with a repository that looks like this:

A diagram showing several commits on a single branch in a theoretical git repository.
Git Branching: A branch is just a “named pointer” to a commit. (Source: Atlassian Git Tutorial)

Let’s say we wanted to reworking our recipes to use a different format. We could continue on our existing branch, but we’re not so sure about this change, so instead we create a new branch to experiment with:

BASH 

git branch yaml-format

The repository history remains unchanged. All you get is a new pointer to the current commit:

A diagram showing a new branch pointer in a theoretical git repository.
Git Branching: The new branch is pointing to the same commit from which it was branched off. (Source: Atlassian Git Tutorial)

Note that this only creates the new branch. To start adding commits to it, you need to move to it with git checkout, and then use the standard git add and git commit commands.

A branch also means an independent line of development. Branches serve as an abstraction for the edit/stage/commit process. New commits are recorded in the history for the current branch, which results in a fork in the history of the project. However, it is really important to remember that each commit only records the incremental change in the document and NOT the full history of changes. Therefore, while we think of a branch as a sequence of commits, each commit is independent unit of change.

Branching Commands

Creating, deleting, and modifying branches is quick and easy; here’s a summary of the commands:

To list all branches:

BASH 

git branch

OUTPUT 

$ git branch
* main
  yaml-format

The asterisk (*) indicates the current branch. To see more information about each branch, including the latest commit on each branch, use the -avv flags:

BASH 

git branch -avv

OUTPUT 

$ git branch -avv
* main        ec240ab Ignore png files and the pictures folder.
  yaml-format ec240ab Ignore png files and the pictures folder.

We can see that, as we have not added any new commits to the yaml-format branch, both branches point to the same commit (ec240ab).

To create a new branch named <branch>, which references the same point in history as the current branch.

BASH 

git branch <branch>

To create a new branch named <branch>, referencing <start-point>, which may be specified any way you like, including using a branch name or a tag name:

BASH 

git branch <branch> <start-point>

To delete the branch <branch>; if the branch is not fully merged in its upstream branch or contained in the current branch, this command will fail with a warning:

BASH 

git branch -d <branch>

To delete the branch <branch> irrespective of its merged status:

BASH 

git branch -D <branch>

Renaming a branch can be done with the -m tag:

BASH 

git branch -m <old-branch-name> <new-branch-name>

Let’s switch over to our new branch so we can start making changes:

BASH 

git switch yaml-format

OUTPUT 

$ git switch yaml-format
Switched to branch 'yaml-format'
Callout

git switch was introduced in Git 2.23 as a more purpose specific command for switching branches. It is functionally similar to git checkout, which is still used widely, but is a more general command with multiple purposes (switching branches, restoring files, etc).

To create a new branch <new> referencing <start-point>, and check it out.

BASH 

git switch -c <new> <start-point>

The special symbol "HEAD" can always be used to refer to the current branch. In fact, Git uses a file named HEAD in the .git directory to remember which branch is current:

BASH 

$ cat .git/HEAD
ref: refs/heads/master

Let’s reformat our recipe to use YAML and commit the changes:

BASH 

nano guacamole.md
name: Guacamole
ingredients:
  avocado: 1.35
  lime: 0.64
  salt: 2
instructions: ""

BASH 

git add guacamole.md
git commit -m "Reformat recipe to use YAML."

Now let’s check our branches again:

BASH 

git branch -avv

OUTPUT 

$ git branch -avv
  main        ec240ab Ignore png files and the pictures folder.
* yaml-format a2b55be Reformat recipe to use YAML.
Challenge

Challenge

Challenge 1: Renaming a file in a branch

We updated our guacamole recipe in the yaml-format branch to use a different format. But now the file extension .md doesn’t make sense anymore. Rename the file to guacamole.yaml and commit the change to the yaml-format branch. Run git status before you commit your changes. Is there anything different about the way this commit looks than in our earlier exercises?

You can use the mv command to rename files in the terminal:

BASH 

mv old-filename new-filename

BASH 

mv guacamole.md guacamole.yaml
git add guacamole.yaml guacamole.md
git status

OUTPUT 

$ git status
On branch yaml-format
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
        renamed:    guacamole.md -> guacamole.yaml

Git is not very clever about most things, but as long as the contents of the file are identical, it can at least figure out that we just renamed the file, rather than deleting one and adding another.

BASH 

git commit -m "Rename recipe file to use .yaml extension."
Challenge

Challenge

Challenge 2:

Key Points
  • A branch represents an independent line of development.
  • git branch creates a new pointer to the current state of the repository and allows you to make subsequent changes from that state.
  • Subsequent changes are considered to belong to that branch.
  • The final commit on a given branch is its HEAD.