SSH, Git, & GitHub

Effectively using Git and GitHub can streamline a lot of your work, including submissions and making sure your files at home and at school are in sync with each other. If done correctly, you can avoid interacting with the GitHub webui entirely, meaning you will no longer need to deal with 2FA and devices that you should not be using in school.

SSH Keys

SSH key pairs are two keys that can be used to authenticate a client to an SSH server, or other service (such as Github). Each key pair consists of a public key and a private key. Never share or upload your private key. Your public key is safe to distribute.

Generating ssh keys

• $ cat ~/.ssh/id_ed25519.pub
  • If you get a message that there is no such file, then you need to make a key.
  • The following commands will make an ssh key pair. (Edwards-curve Digital Signature is the algorithm used to make the keys). DO NOT CONTINUE if you already have a key.
• $ ssh-keygen -t ed25519
  • You will then be prompted to select a location for the keys that will be generated (keep the default).
  • The keys will be stored in the ~/.ssh directory.
  • The private key will be called id_ed25519 and the associated public key will be called id_ed25519.pub.
  • You will then be prompted to create a password protect this key.

Add your public ssh key to GitHub

• Use cat to display the contents of your public key in the terminal:
  • $ cat ~/.ssh/id_ed25519.pub
• Log into your GitHub account in a web browser.
• In the upper-right corner of any page, click your profile “photo”, then click Settings.
• In the user settings sidebar, click SSH and GPG keys.
• Click “New SSH key”
  • Paste your entire public key into the “Key” field. And add a label to the “title” field (e.g. “Stuy CS lab”
  • Click “Add SSH key” and possibly, confirm your git password.
• $ ssh -T git@github.com after this command you will be prompted to type the ssh-key password that you chose when creating the key.
• Read the response message from the above step! If it worked, you should see a message like this:
  • Hi stuydw! You've successfully authenticated, but GitHub does not provide shell access.

Git & GitHub

Git is a program designed to:

• Keep track of changes work over time.
• Maintain backups.
• Sync copies of the same work on multiple computers.
• Help multiple people work on the same project.

A repository is a directory containing work to be tracked by git.

GitHub is A website that provides a central place to store git repositories.

Git Setup & Configuration

• Linux and Mac users should have git installed and accessible via a shell in the Terminal program.
• Windows users should install git and the gitbash shell from here: https://gitforwindows.org/.
• Configure your local git program using these commands. Important: Use your human name (that is not for your username) and your git related email.

  • $ git config --global user.name "Q Tip"
    $ git config --global user.email qtip@tribe.quest
    $ git config --global core.editor nano
    $ git config --global pull.rebase false
    

Standard Git Commands

• Clone : Make a copy of a git repository on a computer.
  • Once a repository is cloned, it will be forever linked to any other copies (including the one on GitHub).
    • $ git clone REPO
  • The cloned copy of a repository on a specific computer is called the local copy.
• Add : Tell git to keep track of a new file.
  • All new files must be added, or git will not recognize them.
  • $ git add FILE
• Commit : Keep track of any new changes you have made to files within the repository.
  • Committing changes only effects the local copy of the repository.
  • $ git commit -a -m "fixed infinite while loop bug in foo()"
• Push : Upload any committed changes to GitHub.
  • $ git push
• Pull : Download any changes from GitHub to your local copy of a repository.
  • $ git pull
• status: List any changes that have been made to the local git repository. Useful to double check if you forgot to add a file, amongst other things.
  • $ git status
• log: Show the commit history of the current repo.
  • $ git history