This tutorial will take you through a basic Git setup and workflow which most developers will use to contribute to repositories on GitHub. Once you have completed this lab, you should:

• understand the role of version control software in code development
• have a working Git setup on your machine
• be prepared to create basic changes to a GitHub project

Supplementary labs will introduce additional common Git commands and resources. Feel free to flag me down or message me if you have any questions! :)

1. First, make sure you have Git installed on your machine. To check if it is installed, open your shell of choice and type git version. This command should return your current version of Git. If it does not, you should go to Git's Download Options and choose the download appropriate for your OS.
2. Go to Github and fork this repository, by navigating to the project page and clicking the Fork button on the upper right corner of the project page.

Hint: This creates a remote copy of the repository under your own account (your very own fork). The fork is connected to the original project, and is now configured for creating pull requests.

3. Open your shell again (Git Bash if using windows), and clone your personal fork to your local machine.

   • Go to your fork's repository on GitHub

   • Click the green Code button. This will give you the project URL for your fork. Copy this URL.

   • In your shell, navigate to the directory where you would like to clone the project. If you are unfamiliar with navigating through the shell, use this page as a helpful guide to cd.

   • Clone your fork repository:

     git clone <project_url>
     

   • If you haven't used Git before, Git may ask you to configure your GitHub credentials. Do this by running the commands below, and then retry your clone command.

     git config ––global user.name “github_username”
     git config ––global user.email “email_address”
     

In this step, you will be making a change to your clone of this repository. Think of an improvement you could make to this project. Which steps did you find confusing? Did you ever feel like I had assumed too much about your knowledge of your system? Here are some examples:

• Fix a typo in this README
• Add additional information to a step that confused you, or was not clear or specific enough
• Insert a helpful link
• Correct a mistake in my markdown styling
• Add more markdown styling to make the README more clear
• Add an additional note about OS specific corrections (i.e. in Windows, you will need to ...)

If do not want to make a change to existing material, create your own supplementary lab under the supplementary_labs(supplementary_labs) folder, using the file supplementary_labs/SupplementaryLabTemplate as a template. Use the lab supplementary_labs/CheckingYourStatus as an example.

1. In your shell, navigate to the repository clone you have made on your local machine.

2. Create a branch to encapsulate the changes you will make for your new "feature":

   git checkout -b "your_new_branch_name"
   

3. Now that you have made and switched to the new branch, make your change. Open up the file you would like to make a change to in your local machine, or alternatively, create you own supplementary lab under supplementary_labs. Make your change, and save it.

4. Run a git status to see your changes, and the filepaths of the files you have changed. Notice they are red because they have not been staged.

   git status
   

   Hint: "Staging" means telling Git which files to track in the next snapshot. The reason we stage changes is so that Git does not have to scan every file in the project for potential changes before every snapshot. Staging also gives the user more control over which changes Git tracks (i.e. if you make a breaking change, don't stage it, and Git will pretend that change never happened in the next snapshot!

5. Stage your changes for commit by running the following command for every file you changed.

    git add <insert the filepath of changed file here>
   

6. Commit your staged changes, by running the following command just once:

    git commit -m "Write a descriptive commit message here about the changes you made"
   

   Hint: "Committing" is recording a snapshot of all your staged changes. A commit is "recorded" in your local version histoy, and can be read, referenced, or reverted in the future.

7. Now, push your local change to your remote fork by running this command:

    git push origin <your branch name>
   

   The first time you run this command, the origin repository URL may not be set. To check if this is the case, use

   git remote -v
   

   This command should tell you whether or not your "origin" alias is set to the correct repository. It should be set to the URL of your fork in GitHub. If it isn't, set it now in Git by running:

   git remote add origin <URL of your remote fork>
   

   Now retry the push command.

   You may encounter an error that says the remote fork contains work your local does not have. If this is the case, it simply means that you have to update your local clone before pushing to your fork. To do this, run

   git pull origin
   

   Then, retry your push command.

8. Open your remote repository on GitHub. On the main project page, there should be a new popup indicating that the branch containing your changes has been pushed from your local repository to your remote repository. Click the button that says Compare & pull request. This will bring you to a menu showing you the commits encapsulated on this branch. Review your changes, and create a pull request.

9. At this point, if another student has modified the same line as you in the same file, you may get a merge conflict. Complete this supplementary lab to resolve the merge conflict, and then retry from step #7.

10. Once the pull request is submitted, I will need to approve it to merge it.

Once I have merged a pull request like yours, you will have pull the code from the original remote project again to get the updated code. To pull from the upstream, first you will have to set the uptream alias by running:

git remote add upstream <URL of the original remote repo owned by me>

Verify that the upstream URL was added correctly by running:

git remote -v

Now, you can pull the updated code from the upstream project into your local copy of the code.

git pull upstream

You now have the most current version of the upstream project in your local machine, and if you navigate to where you made your change, you should see now that it has been incorporated! Great job!

Hint: Remember from the presentation that the code exists in 3 places. Now, the upstream is updated, and the local clone is updated. How do we update the last repository -- your fork? Try to see if you can figure out how to update your fork using Step #7.

This lab is an extremely rudimentary look at the basics. Git has hundreds of other advanced functionalities which students will find extremely useful. Students who have finished the lab, should go complete at least one supplementary lab under the folder supplementary_labs which demonstrates one of these additional functions. Estimated time of completion for the supplementary labs is 5 minutes.

Please let me know if you found this lab helpful. Especially let me know if you found this lab incomplete or confusing. Feedback is greatly appreciated. Thanks for your great work!