Chapter 70: Git

Git is not a graphics topic, but it is a software engineering topic. If you already know and use Git, then feel free to skip to the next chapter.

I won’t try to teach you the fundamentals of Git. There are approximately 1,000,000 tools that can do a better job of that. So far as I know, this is as good as any. If you have any alternatives to recommend, please let me know!

Instead, this chapter is about some motivation for using Git, some best practices, and some general advice. I’ll also touch on a few topics that I think are commonly confusing for early Git users.


There are two different ways to create a git repository. One way is by cloning an existing repository (e.g. from GitHub), and the other is using the init command. Create a git repository by running this command in a directory with files you want to put in a repository:

git init

Add your source code and readme to using the add command it like this:

git add src/
git add resources/
git add ext/
git add CMakeLists.txt
git add
git status
git commit -m 'Add my source, build scripts, and readme!'

Do not include the build/ directory or anything in it. These files should never be checked into a repository.


If you make changes after a commit, or if you cloned the repo instead of downloading it, you also use the add followed by commit command to apply your changes.

git add src/main.cpp
git add
git commit

The status command can be used to see what files have changed, what need to be added, etc.

git status


After you have committed things, you need to push in order to upload your changes to GitHub. You will need to copy either the HTTPS or SSH clone url for your repository.

clone or download

HTTPS will require your GitHub password every time you try to push.

SSH will require that you set up SSH Keys with your GitHub account, but will never ask for a password when you push!

Once you have picked and copied the URL for your repository, run this command if you originally cloned the base code repository:

git remote set-url origin YOUR_COPIED_URL
git push origin master

Otherwise, if you inited the repository instead of cloning it, do this:

git remote add origin YOUR_COPIED_URL
git push origin master

Then your code should be saved in GitHub Classroom!


If your repository already has a origin remote (and you get some sort of error about not being able to add the origin remote), run this command instead:

git remote set-url origin YOUR_COPIED_URL