Working with Git and GitHub

  • What? Git/GH are tools for file versioning.
  • Why? Git/GH are very popular with tech folks.


How Does Git work?

  • Loosely, Git adds some “hidden files” in a directory/folder on your computer.
  • These files help track changes to files in the folder.
  • This folder is called a “repository.”

Git vs. GitHub

  • Git is command line software. GitHub is an online web service for maintaining copies of repos. GitHub Desktop is a GUI wrapper for using Git on your computer.
  • If you know Git, GitHub Desktop is a piece of cake. Nerd out, learn the command line.

Git Commands

  • There are lots of ways to use Git commands. We are only doing the basics.
  • git init: create a repository using an existing folder.
  • git add: tell git you are done working with a file and the file is ready to “commit” to your repository. This is staging the file.
    • counterintuitively, this is also how you tell git that you want to remove a file you delete.
  • git commit: make the modifications to the repository and keep track of them.
  • git push: put your new files on GitHub

What we are going to do

  • Set up Git on your computer
  • Create a repository and connect it to GitHub
  • Fork and suggest changes to a repository

Prereq - Linux/Bash command line

  • Navigate using cd, cd .., and ls

Get started

  • We can move faster if you set up SSH (secure shell) login for Git.
  • Open your Terminal or Git Bash
  • ssh-keygen -t rsa -C “[the mail address you use for GitHub]”
    • No need for passphrase, just “yes” at next
  • Go to your user folder. Cmd+shift+. for Mac or “View Hidden Files” on Windows.
  • Go to the ssh folder.
  • Open the .pub file in a text editor. Copy that key.
  • Go and add that to GitHub account settings (follow along).

Name and Email to Git

  • git config --global “[Your name]”
  • git config --global “[your email]”

Make a repository

  • On the command line, navigate to a folder.
  • Make a new folder in that directory (mkdir).
  • Go into that directory (cd).
  • Create a Hello World R file in that directory (cat > hello.r, print(“Hello World”), Ctrl-d)
  • Initialize Git for that directory (git init)
  • Check the status (git status)
  • Add file we created (git add)
  • Commit the change (git commit -m “First Commit”)

Push our repo to GitHub

  • Go to GitHub in your browser.
  • Log in to your account.
  • Click the new repository button in the top-right.
  • Create the repository
  • Back in your terminal, set your remote connection
    • git remote add origin[the name of your repo]
  • Rename your “master” branch"
    • git branch -M main
  • Push your commit to the main branch
    • git push -u origin main

Collaborate Pt 1

  • Go to Collin’s teaching_repo in GitHub (
  • Fork it. Now you have a copy in your GitHub
  • Open terminal/bash and navigate to the folder in which you want the local copy for the project
  • Clone (download) a local copy:
  • Go into that local folder (cd)
  • Add a connection to the original repository -git remote add collinpaschall
  • Check that the remote is set up
    • git remote -v

Collaborate Pt 2

  • Make some changes to this file using R Studio. Add a line with print(“[your name]”). Save.
  • git add the file
  • git commit -m “[your name] added”
  • git push

Collaborate Pt 3

  • Go to your own version of the forked repository.
  • Click “pull request”.
  • The owner of the original repo is notified.
  • The owner will merge in your changes if s/he likes them.