GIT: Using Branches

13.1. What are branches?

Git allows you to create branches, i.e. named pointers to commits. You can work on different branches independently from each other. The default branch is most often called master.

A branch pointer in Git is 41 bytes large, 40 bytes of characters and an additional new line character. Therefore, the creating of branches in Git is very fast and cheap in terms of resource consumption. Git encourages the usage of branches on a regular basis.

If you decide to work on a branch, you checkout this branch. This means that Git populates the working tree with the version of the files from the commit to which the branch points and moves the HEAD pointer to the new branch.

HEAD is a symbolic reference usually pointing to the branch which is currently checked out.

13.2. List available branches

The git branch command lists all local branches. The currently active branch is marked with *.

# lists available branches
git branch

If you want to see all branches (including remote-tracking branches), use the -a for the git branch command. See Remote tracking branches for information about remote-tracking branches.

# lists all branches including the remote branches
git branch -a

The -v option lists more information about the branches.

In order to list branches in a remote repository use the git branch -r command as demonstrated in the following example.

# lists branches in the remote repositories
git branch -r

13.3. Create new branch

You can create a new branch via the git branch [newname] command. This command allows to specify the commit (commit id, tag, remote or local branch) to which the branch pointer original points. If not specified, the commit to which the HEAD reference points is used to create the new branch.

# syntax: git branch <name> <hash>
# <hash> in the above is optional
git branch testing

13.4. Checkout branch

To start working in a branch you have to checkout the branch. If you checkout a branch, the HEAD pointer moves to the last commit in this branch and the files in the working tree are set to the state of this commit.

The following commands demonstrate how you switch to the branch called testing, perform some changes in this branch and switch back to the branch called master.

# switch to your new branch
git checkout testing

# do some changes
echo "Cool new feature in this branch" > test01
git commit -a -m "new feature"

# switch to the master branch
git checkout master

# check that the content of
# the test01 file is the old one
cat test01

To create a branch and to switch to it at the same time you can use the git checkout command with the -bparameter.

# create branch and switch to it
git checkout -b bugreport12

# creates a new branch based on the master branch
# without the last commit
git checkout -b mybranch master~1

13.5. Rename a branch

Renaming a branch can be done with the following command.

# rename branch
git branch -m [old_name] [new_name]

13.6. Delete a branch

To delete a branch which is not needed anymore, you can use the following command. You may get an error message that there are uncommited changes if you did the previous examples step by step. Use force delete (uppercase -D) to delete it anyway.

# delete branch testing
git branch -d testing
# force delete testing
git branch -D testing
# check if branch has been deleted
git branch

13.7. Push changes of a branch to a remote repository

You can push the changes in a branch to a remote repository by specifying the target branch. This creates the target branch in the remote repository if it does not yet exist.

If you do not specify the remote repository, the origin is used as default

# push current branch to a branch called "testing" to remote repository
git push origin testing

# switch to the testing branch
git checkout testing

# some changes
echo "News for you" > test01
git commit -a -m "new feature in branch"

# push current HEAD to origin
git push

# make new branch
git branch anewbranch
# some changes
echo "More news for you" >> test01
git commit -a -m "a new commit in a feature branch"
# push anewbranch to the master in the origin
git push origin anewbranch:master

# get the changes into your local master
git checkout master
git pull

This way you can decide which branches you want to push to other repositories and which should be local branches. You learn more about branches and remote repositories in Remote tracking branches.

13.8. Switching branches with untracked files

Untracked files (never added to the staging area) are unrelated to any branch. They exist only in the working tree and are ignored by Git until they are committed to the Git repository. This allows you to create a branch for unstaged and uncommitted changes at any point in time.

13.9. Switching branches with uncommitted changes

Similar to untracked files you can switch branches with unstaged or staged modifications which are not yet committed.

You can switch branches if the modifications do not conflict with the files from the branch.

If Git needs to modify a changed file during the checkout of a branch, the checkout fails with a "checkout conflict" error. This avoids that you lose changes in your files.

In this case the changes must be committed, reverted or stashed. You can also always create a new branch based on the current HEAD.

13.10. Differences between branches

To see the difference between two branches you can use the following command.

# shows the differences between
# current head of master and your_branch

git diff master your_branch

You can use commit ranges as described in Commit ranges with the double dot operator and Commit ranges with the triple dot operator. For example, if you compare a branch called your_branch with the master branch the following command shows the changes in your_branch and master since these branches diverged.

# shows the differences in your
# branch based on the common
# ancestor for both branches

git diff master...your_branch

See Viewing changes with git diff and git show for more examples of the git diff command.