Open Source 101: Version Control Systems and Git

Introduction

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Open source software (OSS) is software released under licenses that allow inspection, modification, and redistribution of source code. The open source movement has seen explosive growth since the late 1990s. Today, open source projects form the foundation of global technology infrastructure. From tiny hobby projects to massive platforms like Linux and Android that power billions of devices, open source is ubiquitous across the industry.

The economic impact of open source is staggering. According to recent data, the typical application stack contains 80-90% open source components. As of 2022, the market cap for open source ecosystem companies reaches nearly $1 trillion. About 36% of developers are now contributing to open source projects as collaboration continues to accelerate.

So what enables effective large-scale collaboration in open source software development? The answer is version control systems. By tracking code changes over time, version control allows coordination across potentially thousands of developers working in parallel.

This article will provide you with a definitive guide to leveraging open source workflows, from understanding version control fundamentals to mastering Git in practice. Let‘s start with the role version control systems play in managing software change.

Understanding Version Control Systems

A version control system (VCS) records changes made to code, documents, or other information stored as file system files. As updates occur, the VCS snapshots relevant metadata to track the timeline of changes. By managing this revision history, VCS provides key collaboration and coordination abilities for development teams.

Key Abilities of Version Control:

  • Chronological change tracking to reconstruct evolution
  • Traceability for coordination, accountability, and resolving issues
  • File revision histories to roll back unwanted changes
  • Support simultaneous workflows for merging parallel development

Version control brings order to the chaos of uncontrolled changes. An analogy for VCS is tracking the revision history for a document. As multiple authors make edits, a system snapshots file differences, logs attribution data on who made what change, and handles merging parallel edits cleanly to prevent overwrite conflicts.

Now imagine this document version tracking on a massive, enterprise scale with thousands of collaborators. Welcome to open source!

Adoption By The Numbers

Version control usage has rapidly expanded:

  • 97% of organizations report using version control systems
  • 87% of developers use version control daily
  • Most popular systems: Git (71%), Subversion (50%), Mercurial (12%)

Under the hood, version control systems implement identity tracking, storage snapshots, artifact tree representations, and differencing algorithms to reconstruct history. They generally fall into two architectural paradigms: centralized and distributed.

Centralized Version Control

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Distributed Version Control

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Understanding Git Basics

Today, Git dominates as the most broadly adopted distributed version control system. Originally created to support Linux kernel development, Git‘s lightning fast performance, superior branching capabilities, and distributed architecture causes it to outshine older centralized systems.

Core Git Abilities and Advantages

  • Distributed development (offline work, global collaboration)
  • Powerful branches for isolated experiments
  • Cryptographic data integrity protection
  • Fast performance for large codebases
  • Staging area for flexible commit workflow
  • Complete revision history and source control

Now let‘s jump into using Git for a solo developer workflow. We will cover installation, setup, basic commands, and visualizing the standard Git commit workflow.

Installing and Configuring Git

Installing Git

The first step is downloading and installing a Git client locally:

  • Windows – Download Git for Windows installer
  • MacOS – Install Xcode command line tools or standlone Git package
  • Linux – Use system package manager (APT, Yum, etc.)

Verify the install with:

git --version

This will output the version if Git is installed properly.

Configuring Git

Next we need to set the user name and email for commit authorship metadata:

git config --global user.name "Your Name"
git config --global user.email "[email protected]"

This links your commits to your user identity. We can inspect the active config with: 

git config --list

Connect Git Remotes

To publish code or collaborate, we need to connect to a shared remote Git repository. Popular Git remotes include:

  • GitHub – Cloud hosting for Git repositories
  • GitLab – Self-hosted Git repository management
  • BitBucket – Git and Mercurial repositories

We will use GitHub, which offers unlimited public and private repositories for individuals and teams. This example connects my GitHub account via SSH…

SSH Key Setup

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Git Command Basics

Now that Git is configured properly, let‘s overview some essential commands.

Core Git Commands and Workflow

Git features a simple three stage workflow. Files can live in three main states:

  1. Working Directory – Regular files we edit
  2. Staging Index – Snapshots of changes ready to commit
  3. Git Repository – Commit history with file snapshots

Here are commands for managing file state transitions:

# Pull latest history from remote
git pull origin main

# Edit files in working directory 
vim index.js

# Add file changes to staging index 
git add index.js

# Commit snapshot of staging index
git commit -m "Update index page text"

# Push commits to remote
git push origin main

And a visual of core Git workflow:

Inspecting History and Status

We can also diff file changes, browse past commits, and view status:

# Show unstaged file changes
git diff

# List commits chronologically 
git log

# View high level repo status
git status

Now that we have a handle on basic workflow, let‘s look at leveraging branches.

Git Branching Workflows

Branching allows isolated and parallel development. Instead of one central code timeline, development can fork into branches:

                  main Branch        
                 /              
Initial commit->Version 1.0---->Version 1.1
                 \ 
                  Feature Branches

Common branching strategies include:

  • Main codebase branch + user feature branches
  • Main code + develop integration branch + features
  • Environment branches (dev/test/prod)

Let‘s walk through a collaborative feature branch example…

1. Developer Creates Feature Branch

# Checkout new branch 
git checkout -b login-module

This branch allows working on a login module isolated from main.

2. Developer Builds Feature

Commits related changes:

git add login.py
git commit -m "Add user auth module"

3. Developer Pushes Feature Branch

So other contributors can access: 

git push origin login-module

Now a teammate can review progress on the login-module branch.

4. Teammate Creates Pull Request

……

Additional Git Capabilities

Beyond fundamental workflows, Git offers powerful advanced capabilities:

  • Rebasing – Rearrange commits for linear history
  • Git Hooks – Script triggers for automation
  • Stashing – Temporarily stash unfinished changes
  • Git LFS – Support large binary files
  • Bisect – Binary search history

Let‘s explore rebasing to cleanly integrate feature branch work.

Leveraging Rebasing

By default, Git merge creates special merge commits. Rebasing moves branch commits onto main branch tip:

                                     Feature   
                                    /           
A--B--C--D              main   E--F--G              
                   `git rebase` =>  
                             A--B--C--D--E‘--F‘--G‘  main

This enables:

  • Linear commit history on main branch
  • Conflict resolving with branch commits

Overall, rebasing produces clean integration results.

The full power of Git expands far beyond this intro guide. Now let‘s look at engaging in open source projects.

Open Source Collaboration

Let‘s shift our focus to collaborating in the open source ecosystem via Git and GitHub. Some starting points:

Finding Open Source Projects

There are millions of open source projects spanning applications, libraries frameworks, and more across every language. GitHub Explore surfaces trending projects. Other places to look include documentation sites for languages and frameworks which highlight relevant open source packages.

Contributing Through Documentation

Fixing documentation typos and inaccuracies is a starting point to understand project internals. From there issues and bug fixes provide first code contributions.

Engaging in Code Reviews

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Conclusion

We have explored the immense power of version control systems for scaling software collaboration along with Git fundamentals. Some parting advice:

  • Start using version control if you haven‘t already!
  • Experiment locally then connect cloud repository
  • Isolate experiments through branching
  • Invest time mastering rebase, bisect, hooks

The capabilities transform software development. Now go use your new Git superpowers to start contributing to open source today!

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