Git & GitHub Guide

Introduction

Git is a distributed version control system used to track and manage source code. GitHub is a platform for hosting Git repositories online, used for collaboration, issues, pull requests, and project management.

Setup & Configuration

To install Git:

Windows: Download from git-scm.com
Mac: Use brew install git
Linux: sudo apt install git

Configure your identity:

git config --global user.name "Your Name"
git config --global user.email "you@example.com"

Essential Git Commands

git init – Start a repository
git clone URL – Copy a remote repo
git add file – Stage files
git commit -m "msg" – Save snapshot
git push/pull – Sync with remote
git log – View commit history
git status – Show working tree state

Git File Lifecycle

Files move through these stages:

Untracked → Staged → Committed → Modified

Branching & Merging

git branch – List branches
git branch name – Create branch
git switch name – Move to branch
git merge – Merge two branches
git checkout -b feature – Create and switch

Git Stash

git stash – Temporarily save uncommitted work
git stash list – View stashed items
git stash apply – Reapply changes

Restore & Reset

git restore file – Discard changes
git reset --soft HEAD~1 – Undo last commit
git reset --hard – Full reset to last commit

Rebase vs Merge

Merge: Preserves history and creates a merge commit.

Rebase: Rewrites history for a cleaner, linear timeline.

git rebase main
git merge feature

Git Squash

Combine multiple commits into one:

git rebase -i HEAD~n → Change pick to squash

Tags & Releases

git tag v1.0 – Mark a release
git tag -a v1.0 -m "release note"
git push origin v1.0 – Push tag

Git Workflows

Git Flow: Uses branches like main, develop, feature/, release/, hotfix/.

GitHub Flow: Create branch → Work → PR → Review → Merge

GitHub Usage

Fork repos to your account
Clone using git clone URL
Push changes: git push origin branch
Create PR from GitHub UI

Open Source Contribution

Fork the repo
Create new branch
Make changes and commit
Push to your fork
Create Pull Request (PR)
Get reviewed & merged