Git Switch Branch – How to Change the Branch in Git

Switching branches is something you’ll need to do often in Git.

To do this, you can use the git checkout command.

How to create a new branch in Git

To create a new branch in Git, you should use the git checkout command. Consequently, you need to pass the -b flag along with a branch name. Consequently, this command will not only create a new branch but also switch to it immediately. Therefore, you will be positioned on the new branch right away, enabling you to start working on it without any additional steps.

This process will result in the creation of a new branch based on the current branch. Consequently, the new branch will inherit the exact history from the point where the original branch was branched off.

Assuming you are currently on a branch called master:

(master)$ git checkout -b my-feature
Switched to a new branch 'my-feature'
(my-feature)$

Here you can see a new branch created called my-feature which was branched off of master.

How to switch to an existing branch in Git

To switch to an existing branch, you should use the git checkout command once again. Consequently, omit the -b flag and provide the name of the branch you wish to switch to. As a result, this command will not only change your working branch but also update your working directory to reflect the selected branch.

(my-feature)$ git checkout master
Switched to branch 'master'
(master)$

There is also a handy shortcut for returning to the previous branch you were on by passing – to git checkout instead of a branch name:

(my-feature)$ git checkout – Switched to branch ‘master’ (master)$ git checkout – Switched to branch ‘my-feature’ (my-feature)$

How to check a specific commit

To checkout or switch to a specific commit, you can also use git checkout and pass the SHA of the commit instead of a branch name.

After all, branches are just pointers and trackers of specific commits in the Git history.

How to find a commit SHA

One way to find the SHA of a commit is to view the Git log.

You can view the log by using the git log command:

(my-feature)$ git log
commit 94ab1fe28727b7f8b683a0084e00a9ec808d6d39 (HEAD -> my-feature, master)
Author: John Mosesman <johnmosesman@gmail.com>
Date:   Mon Apr 12 10:31:11 2021 -0500

    This is the second commmit message.

commit 035a128d2e66eb9fe3032036b3415e60c728f692 (blah)
Author: John Mosesman <johnmosesman@gmail.com>
Date:   Mon Apr 12 10:31:05 2021 -0500

    This is the first commmit message.

On the first line of each commit after the word commit is a long string of characters and numbers: 94ab1fe28727…

This is called the SHA. A SHA is a unique identifier that is generated for each commit.

To checkout a specific commit, you just need to pass the commit’s SHA as the parameter to git checkout:

(my-feature)$ git checkout 035a128d2e66eb9fe3032036b3415e60c728f692
Note: switching to '035a128d2e66eb9fe3032036b3415e60c728f692'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 035a128 a
((HEAD detached at 035a128))$

Note: You generally only need to use the first few characters of the SHA—as the first four or five characters of the string are most likely unique across the project.

What is a detached HEAD state?

The result of checking out a specific commit puts you in a “detached HEAD state.”

From the documentation:

[a detached HEAD state] means simply that HEAD refers to a specific commit, as opposed to referring to a named branch

The HEAD (one of Git’s internal pointers that track where you are in the Git history) has diverted from the known branches, and so changes from this point would form a new pathway in the Git history.

Git wants to make sure that that is what you are intending, so it gives you a “free space” of sorts to experiment—as described by the output:

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

From this position, you have two options:

• Experiment and then throw away your changes by returning to your previous branch
• Work from here and start a new branch from this point

You can use the git switch – command to undo any changes you make and return to your previous branch.

If you instead want to keep your changes and continue from here, you can use git switch -c <new-branch-name> to create a new branch from this point.

Conclusion

It’s not only a versatile tool but also a multi-purpose command. You can use it while creating new branches. On the other hand, use it when switching to an already existing branch. You could use it to check out certain commits. As such, it offers varied functionality, thus being of great significance in diverse Git operations.

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