GitHub: What It Is and How It Works

Born as a simple tool to host open source software projects, GitHub today represents the largest collaborative community ever created, as well as the archive that preserves the history of the digital technologies of our time.

Today, almost every line of code written passes at least once through GitHub’s servers, a platform that hosts the work of over 100 million developers and more than 400 million projects.

What is GitHub?

GitHub is an online platform owned by Microsoft that allows developers to store, manage, and track changes to source code projects while collaborating with other programmers.

GitHub is based on Git, a distributed version control software created by Linus Torvalds in 2005 to efficiently coordinate the work of the thousands of contributors active on the Linux kernel—who had recently been forced to stop using the BitKeeper system that had been in place until then.

Torvalds’ “personal” need soon turned into a platform hosting over 100 million developers and containing more than 400 million repositories. Launched in 2008, GitHub is now the largest and most widespread hub for open source projects in the world.

The difference between Git and GitHub

The fundamental difference between Git and GitHub lies in the fact that Git is software that runs locally, while GitHub is one of the cloud hosting services that uses the technology developed by Torvalds.

Git is local version control software that tracks file history by taking a snapshot of the code every time a change is made (commit). One of its main features is that it allows you to restore any previous version of files and create parallel work branches to test new code without affecting the main version of the project.

GitHub, as mentioned, is the Microsoft-owned website that hosts Git projects online to make them available to other developers who need or want to collaborate. The same service is also offered by other platforms such as GitLab and Bitbucket, but GitHub can safely be considered “the standard.” 

In fact, the platform quickly managed to become a reference point for the entire open software community (for example, by offering unlimited free space for public projects and allowing developers to have a profile page that collects all their contributions in a sort of public portfolio).

GitHub: what is it for?

The main functions of GitHub can be summarized as follows:

• Version control (GitHub versioning): this is Git’s core purpose and consists of tracking every change to the code, allowing you to return to any previous version and work in parallel on the same project without interfering with the main code;
• Repositories and hosting: GitHub stores and makes accessible via the web the code of millions of projects (repositories), from proprietary software of small businesses to the (open source) code that helped land humans on the Moon with the Apollo 11 mission;
• Collaboration: it provides developers with tools that allow hundreds of developers to work on the same project simultaneously without overwriting each other’s work, such as “pull requests” (used to propose changes and have them reviewed) and “issues” for bug tracking.

More recently, GitHub has also taken on another strategic role: with the integration of GitHub Copilot, an artificial intelligence based on OpenAI models trained on GitHub’s vast archive, the platform has become a true programming assistant capable of suggesting code in real time, fixing errors, and automating particularly repetitive or complex tasks.

GitHub: how does it work?

Before GitHub, contributing to someone else’s project meant emails and manual patches. Today, to contribute, it’s enough to take someone else’s project, copy it (fork), modify it, and ask the author to accept the changes (pull request).

Let’s take a closer look at how it works. Unlike other systems, Git operates through snapshots: every time there is a change (commit), it takes a complete snapshot of the entire state of the project at that moment. 

Each snapshot is associated with a unique ID (hash) calculated from the code content, which also includes author, date and time, and messages. This Git-specific mechanism makes it virtually impossible to corrupt or alter the software. Even changing a single bit would alter the “signature” of the snapshot.

Another central feature of how GitHub works lies in its pointer system (branching), which is what allows hundreds of people to work together on the same software project. The Main pointer is a label that indicates the latest official version of the software. Alongside it, other bookmarks may exist that point to branches, i.e., the “experimental” branches of the software that are not yet part of the main project.

These bookmarks, which update automatically at commit time, allow different parts of the software to be developed in parallel without developers’ work interfering with one another.

How to use GitHub

To start using GitHub, the first step is to create an account on github.com and install Git on your computer. After that, you can choose between three different ways to interact:

• From the command line, using terminal commands;
• Via the GitHub Desktop app, which offers a very easy-to-use graphical interface, ideal for those unfamiliar with Git;
• Directly on the web interface, which allows you to perform many core actions (create repositories, upload files, fork, etc.).

In any case, everything starts on the developer’s computer, where the project’s Git folder/repository is created. Git tracks all changes made to the code. When the project is ready to be shared, it is uploaded (push) to GitHub, which then contains a copy of the repository that all collaborators can work on.

Collaborative work takes place through three key tools:

 

• Fork: used to copy a project so you can work on it without interfering with the original;

• Pull request: if the fork includes improvements over the original code, you ask the author to approve the changes made;

• Merge: approved changes are automatically “merged” into the original code, and the branch is integrated into Main.