The Open Engine: Git & GitHub Mastery

Unlocking the world of professional collaboration. Learn the tools that power the global software engineering community.

What is Git & GitHub?

Before Git, developers used to email folders of code to each other. It was a nightmare. Git is a Version Control System (VCS), a tool that helps track changes in code and allows thousands of people to work on the same project simultaneously without breaking each other's work.

GitHub is the social layer on top of Git. It's where the world's most important software (like Linux, React, and Python) lives and grows.

Setup of Git

To start using Git, you need a terminal. On Windows, Git Bash is recommended alongside an editor like VS Code.

You can download Git from: https://git-scm.com/download/win

git --version   # Verify Git installation

Basic Commands

Navigating the Terminal

cd [path]       # Change directory
ls              # List files in the current folder
ls -a           # List all files, including hidden ones

Init Command

Used to create a new Git repository in your current folder.

git init
git remote add origin "link"  # Connect local repo to remote
git remote -v                 # Verify remote connection

The Core Workflow

The fundamental process of contributing code follows this path:

Clone & Status

Clone: Downloading a repository to your local machine.

git clone "project link"   # Clone using HTTPS link from GitHub repo

Status: Displays the state of your working directory and staging area.

git status

File states transition between: untracked, modified, staged, unmodified.

Add, Commit & Push

Add: Adds new or changed files in your working directory to the Git staging area.

git add "file name"      # Add a specific file
git add .                # Add all current changes

Commit: It's the record of a change.

git commit -m "type your message"

Push: Upload local repository content to a remote repository.

git push origin main     # Standard push command
git push -u origin main  # Push and set upstream

Fearless Branching

In a professional environment, everyone makes their own copy to work on, called a Branch (e.g., a feature branch diverging from main or master default branch). It's a sandbox where you can experiment safely without affecting others.

git branch                    # Check branches
git branch -M main            # Rename branch to 'main'
git checkout [branch name]    # Navigate between branches
git checkout -b [new branch]  # Create and switch to new branch
git branch -d [branch name]   # Delete branch

Merging & Pull Requests

After finishing a feature, you need to bring changes back.

Way 1: Merge Commands

git diff [branch name]        # Compare commits, branches, files, etc.
git merge [branch name]       # Merge another branch into your current one

Way 2: Pull Request (PR)

A Pull Request lets you tell others about changes you've pushed. It's a conversation where you ask teammates to review your code.

Resolving Merge Conflicts: An event that takes place when Git is unable to automatically resolve differences in code between two commits. Typically resolved during a PR review or a Git merge manually.

Keeping Sync: Pull & Fork

Pull: Used to fetch and download content from a remote repo and immediately update the local repo to match that content.

git pull origin main

Fork: A fork is a rough copy. It's a new repository that shares code and visibility settings with the original "upstream" repository. Ideal for contributing to Open Source projects you don't own.

Undoing Changes

Mistakes happen. Here's how to go back in time safely.

git log                       # Check history to find commit hash

# Case 1: Staged changes (Unstage)
git reset [file name]
git reset

# Case 2: Committed changes (undo 1 recent commit)
git reset HEAD~1

# Case 3: Committed changes (discard changes entirely to a commit)
git reset [commit hash]
git reset --hard [commit hash]  # WARNING: Deletes uncommitted work!