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Chapter 2 — Git vs GitHub

Overview: Why Does the Distinction Matter?

The single most common source of confusion for new users is conflating Git and GitHub. They are two separate things that work together. Understanding the difference is essential before any command makes sense.

What Is Git?

Git is a version control system — a program that runs on your computer.

It tracks changes to files over time. When you run git commit, Git takes a snapshot of your staged files and records it in a local database stored in the hidden .git/ folder inside your project directory.

Key properties of Git:

  • Local. Git works entirely on your machine. No internet connection is needed to commit, branch, diff, or view history.

  • Distributed. Every clone of a repository contains the complete history. There is no single "master copy" — although in practice, one remote serves as the canonical reference.

  • Free and open source. Created by Linus Torvalds in 2005 for Linux kernel development.

Git is installed as a command-line tool:

git --version
# git version 2.44.0

What Is GitHub?

GitHub is a web platform that hosts Git repositories.

It provides:

  • Remote storage — a place to push your local commits so others can access them.
  • Collaboration tools — Pull Requests, code review, issue tracking, project boards.
  • Visibility — repository pages, contributor graphs, commit history browsing.
  • Automation — GitHub Actions for CI/CD, automated testing, and deployment.

GitHub is where the group organises its work. You interact with it through:

  1. The GitHub web interface (browser)
  2. Git commands on your terminal (via SSH)
  3. The GitHub CLI (optional, not covered in this handbook)

Other platforms

GitLab and Bitbucket offer similar services. This group uses GitHub exclusively. The concepts in this handbook transfer to other platforms, but the specific interface instructions do not.

How They Relate: Local ↔ Remote

graph LR
    subgraph "Your Computer (Local)"
        W[Working Directory] -->|git add| S[Staging Area]
        S -->|git commit| L[Local Repository .git/]
    end

    subgraph "GitHub (Remote)"
        R[Remote Repository<br/>origin/main]
    end

    L -->|git push| R
    R -->|git pull / git fetch| L

The workflow in one sentence: You edit files locally, commit them to your local Git repository, then push those commits to GitHub where your collaborators can see and review them.

Key Vocabulary

Understanding these terms is required before proceeding:

Term Where it lives Meaning
Repository Local & Remote The project folder tracked by Git, including all history
Commit Local (then pushed) A saved snapshot with a message, author, and timestamp
Branch Local & Remote An independent line of commits; main is the default
Remote Remote A named reference to a repository on GitHub; default name is origin
Clone — Copying a remote repository to your local machine
Push — Sending local commits to the remote
Pull — Fetching remote commits and integrating them locally
Fork Remote A personal copy of someone else's repository on GitHub

Fork ≠ Clone

Cloning downloads a repository to your machine. Forking creates a copy of a repository under your own GitHub account. In this group, students clone the group repository — they do not fork it.

What the Group Uses GitHub For

In this group, GitHub serves as:

  1. The canonical remote — origin/main is the authoritative version of the code.
  2. The Pull Request gate — all changes are reviewed on GitHub before merging.
  3. The issue tracker — bugs, tasks, and ideas are logged as Issues.
  4. The release record — tagged releases mark paper submissions and milestones.

Common Mistakes

  1. Thinking "I pushed to Git." You push to GitHub (the remote). Git is the local tool. Say "I pushed to GitHub" or "I pushed to origin."

  2. Editing files directly on GitHub's web editor for anything beyond trivial one-line fixes. Always work locally, then push.

  3. Confusing git pull and git clone. clone is a one-time operation to get a local copy. pull is used regularly to sync changes after you already have a clone.

Best Practice Summary

  • Git is a local tool; GitHub is a remote hosting platform. They are different things.
  • Every git push sends commits from your local Git repo to GitHub.
  • Every git pull brings commits from GitHub into your local Git repo.
  • Students clone the group repository — they do not fork it.
  • The remote is named origin by default; origin/main is the canonical branch.

Checklist

  • I can explain the difference between Git and GitHub in one sentence.
  • I understand what "local" and "remote" mean in this context.
  • I understand the role of origin and main.
  • I know the difference between clone and fork.

Exercises

  1. Diagram. On paper (or a whiteboard), draw the local ↔ remote diagram from memory. Label: working directory, staging area, local repo, remote repo, and the four operations: add, commit, push, pull.

  2. Explore GitHub. In the group's GitHub repository, find:

  3. The list of branches
  4. The commit history of main
  5. One closed Pull Request

  6. One open Issue You do not need to interact — just locate them.

  7. Vocabulary check. Ask a colleague (or write in your notes): What happens step by step when you run git push origin feature/my-task?