Git and GitHub Explained In 10 Minutes |

Welcome to this guide on Git. In this article, we'll explore the most important features of Git, starting with why version control is essential for modern development.

We will cover several key architectural decisions that have contributed to Git's popularity. First, the fact that Git is a distributed version control system (DVCS). We will compare a DVCS with a centralized version control system to understand the advantages it provides. We'll also discuss the snapshot system that Git follows, where a complete snapshot of your project is taken with every commit.

After exploring these core concepts, we will look at a short history of Git and review a few popular version control systems that came before it.

Then, we'll dive into the practical side of things. We'll discuss creating a remote repository using GitHub, a platform that enhances Git with powerful collaboration features. We will walk through a practical example of creating a new local Git repository and pushing it to a remote repository on GitHub.

Finally, we'll get a deep dive into how Git organizes and stores your code through its layered architecture, including the working directory, staging area, local repository, and remote repository. We'll trace how a file moves through these stages and look at what happens in the background when you commit your code.

Why Is Version Control Essential?

A version control system (VCS) is a tool that tracks changes to files over time. When developing software, code constantly evolves, often with numerous developers working on the same files. A VCS is crucial for managing this complexity efficiently and, more importantly, for enabling collaboration without conflict. The primary purpose is to maintain a complete history of the code and ensure developers can work together without overwriting each other's work.

Here’s why it's indispensable:

Collaboration: Multiple developers can work on the same project simultaneously without interfering with each other's changes.
History Tracking: You can easily view, compare, and restore previous versions of your code. If you need to access the code as it was a year ago, a VCS makes it possible.
Branching: Modern development involves multiple environments and release cycles. Branching allows you to create isolated lines of development, enabling different team members to work on various features or fixes simultaneously.

How Git's Distributed Model Improves Collaboration

There are two main types of version control systems: centralized and distributed.

Centralized Version Control Systems (CVCS): A single central server stores all versions of the code. When a developer checks out code, they get a snapshot of the current version, not the entire history.
Distributed Version Control Systems (DVCS): Every developer has a complete copy of the repository, including the full history. When you clone a Git repository, you get everything.

Let's compare them:

Git's distributed nature enhances collaboration and efficiency by providing:

Complete Local History: Every developer’s local copy includes the full project history, making offline work seamless.
Offline Branching: Local clones contain all remote branches, allowing developers to switch, create, or merge branches without a network connection.
Faster Operations: Most Git commands like commit and diff are local, resulting in near-instant performance.
Enhanced Reliability: If the main server goes down, any local copy can be used to restore the entire project.

Why Git's Snapshot System Is a Game-Changer

Instead of storing just the differences (deltas) between files, Git's snapshot-based system captures the entire state of your project at each commit. Think of it as a photograph taken every time you save your work.

How it Works: Git stores a complete version of each changed file. If a file hasn't changed in a commit, Git simply links to the previous identical version rather than duplicating it. This process is highly efficient, as Git compresses the files and stores them in its own internal representation.
Contrast with Delta-Based Systems: In delta-based systems (like Subversion), only the changes between file versions are stored. To reconstruct a specific version, the system must start from a base version and apply a sequence of deltas, which can be slow and complex, especially for branching.

Let's look at an example:

Snapshot-Based System (Git) 1. Commit 1: You create a file. Git stores a full snapshot of file_v1. 2. Commit 2: You modify the file. Git stores a new, full snapshot of the modified file_v2. 3. Commit 3: You modify it again. Git stores another full snapshot of file_v3. Retrieving any version is instant because Git already has the complete file.

Delta-Based System (Subversion) 1. Commit 1: You create a file. The system stores the full file_v1. 2. Commit 2: You modify the file. The system stores only the delta (the difference between v1 and v2). 3. Commit 3: You modify it again. The system stores the delta from v2. To get file_v3, the system has to take file_v1, apply the first delta, and then apply the second delta. This calculation becomes time-consuming in projects with thousands of files.

The advantages of Git's snapshot system are clear: * Speed: Quickly access any commit without calculating changes. * Reliability: Full file versions are always available, reducing the risk of corruption. * Simplified Merging: Merging is faster because Git works with complete file versions, not a series of patches.

A Brief History of Git

In 2005, the Linux kernel development team, led by Linus Torvalds (the creator of Linux), needed a powerful, distributed version control system. The proprietary tool they were using was expensive, unreliable, and centralized. Torvalds built Git to solve these problems based on three key design principles:

Speed: Git was designed to be exceptionally fast, even for massive projects.
Security: Every change is tracked and verifiable through cryptographic hashing (SHA-1).
Decentralization: Developers can work independently offline and connect only when needed.

2005: Git is released as an open-source project.
2008: GitHub is launched, making Git widely accessible for collaborative projects online.
2010s: Git adoption surges as countless open-source communities and companies migrate from older systems like Subversion (SVN).
2018: Microsoft acquires GitHub, further boosting Git's presence in the enterprise market.

Today, Git is the industry standard for version control. While GitHub is the most popular hosting platform, several other excellent options exist:

GitLab: An all-in-one DevOps platform with integrated CI/CD, container registry, and monitoring.
Bitbucket: Developed by Atlassian, it offers strong integration with tools like Jira and Trello.
Azure Repos: Microsoft's Git hosting service, tightly integrated with Azure DevOps.
AWS CodeCommit: Amazon's managed Git service, integrated with the AWS ecosystem.
Cloud Source Repositories: Google Cloud's Git-compatible service with deep integration into its platform.

Popular Version Control Systems Before Git

Before Git dominated the landscape, several other systems were popular:

CVS (Concurrent Versions System): A simple, lightweight, and centralized VCS. It had limited merge support and was prone to errors in large projects.
Subversion (SVN): Also centralized, SVN was more user-friendly than CVS. However, it was network-dependent for most operations, and performance degraded with large repositories.
Perforce: A centralized VCS known for its excellent performance with large codebases and binary files, making it a favorite in the game development industry.

Here's a quick comparison of Git and its main predecessor, Subversion:

What is GitHub?

GitHub is a web-based platform built on top of Git. It provides a cloud-based home for your Git repositories, enhancing them with powerful tools for team collaboration, code review, and project management. Think of it as Git++—Git in the cloud with a suite of extra features.

Key features include:

Hosted Repositories: Create public repositories to share with the world or private repositories for secure, team-only collaboration.
Pull Requests: A mechanism for proposing changes and requesting code reviews, enabling peer collaboration before code is merged.
Issue Tracking: A built-in system to manage bugs, feature requests, and tasks directly within your repository.
Discussions: A dedicated space for questions, ideas, and decisions, keeping conversations organized.
GitHub Actions: An integrated CI/CD (Continuous Integration/Continuous Deployment) tool to automate workflows for building, testing, and deploying your code.
GitHub Pages: A feature to host static websites (like portfolios, documentation, or demos) directly from your repository.

Git vs. GitHub

How Git Organizes Your Code: The Layered Architecture

Git uses a layered approach to manage your code, which gives you fine-grained control over your work:

Working Directory: This is your local project folder where you create, edit, and delete files.
Staging Area (or Index): This is an intermediate area where you prepare a set of changes before committing them. It allows you to group related changes into a single, clean commit.
Local Repository: This is your personal, complete copy of the project's history, stored in a hidden .git directory. When you commit, your staged changes are saved here.
Remote Repository: This is the shared repository, typically hosted on a platform like GitHub, where the team collaborates and syncs their work.

The Journey of a File in Git

A file moves through multiple stages before it is safely stored in the remote repository:

You create or modify a file in your Working Directory.
You use git add to move the changes from the working directory to the Staging Area.
You use git commit to save the snapshot from the staging area into your Local Repository.
You use git push to upload your commits from the local repository to the Remote Repository, sharing them with your team.