Branches make working with commits easier
A branch is just a reference to a commit, it has a human-readable name and identifier. Instead of using the SHA-1 hash to reference a commit we can now use the name of a branch.
When creating a repository using
git init a branch named 'master' is created
for us, it is currently pointed at our latest commit.
Let's designate 'master' as the branch for our main line of development, anything on that branch should be stable. If we want to test out new features without breaking the main line then we can create new branches.
We want to add a new file to our current project, but we don't want to mess up 'master'.
We can see all of the branches in our repository.
git branch # stdout: master
To add our new feature we want to add a new branch. Our new feature is adding information about our favourite animal so let's call the branch something descriptive like 'favourite-animal'.
git branch favourite-animal # If we do a 'git branch' now we'll see our new branch is created, but we're # still on master. Let's 'checkout' our new branch. git checkout favourite-animal
Now that we have our branch created let's take a look at our commit history
git log, this will give us information about what commit each branch is
currently pointing to.
Let's make some changes to our new branch and commit them.
echo 'My favourite animal is a <your-favourite-animal>!' > animal.txt git add animal.txt git commit -m "Add favourite animal"
We now have a repository that looks like this.
Branches are stored in the
.git/refs/heads directory as files. If we view the
contents of any of these files they just contain the SHA-1 hash of the commit
the branch is currently pointing to.
When we were doing
git log you may have seen 'HEAD' mentioned in the log.
HEAD points to whatever is currently checked out. At the moment we have the
'favourite-animal' branch checked out so it will point to that. HEAD is a file
cat .git/HEAD # stdout: ref: refs/heads/favourite-animal
We have created a branch that has information about our favourite animal. Now let's create another branch from master and add information about our favourite TV show. We are currently on the branch 'favourite-animal'. We need to create our new branch from master.
# Create a new branch named favourite-show from the branch master git branch favourite-show master git checkout favourite-show
We'll leave the rest to you.