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🌀 Git: Introduction to Version Control

🔍 What is Git?

Git is the most widely-used distributed version control system for tracking changes in source code during software development. It helps developers collaborate, manage changes, and maintain code quality over time.

Think of Git as a time machine for your codebase.

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🚀 Key Features of Git

• Local-first: Git stores your entire project and its history locally, so you can work offline.
• Efficient change tracking: It records line-by-line changes, making it easy to review or roll back.
• Seamless collaboration: Git enables multiple developers to contribute to the same codebase without conflict.

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📦 What is a Git Repository?

A Git repository (or repo) is a project directory with a special hidden folder called .git. This folder stores metadata, commit history, branches, and more.

A Git repo = your project + its full timeline of changes.

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🔄 The Three States in Git

Git tracks your files through three distinct states:

State	Description
Modified	You’ve made changes to a file, but haven’t staged it yet.
Staged	You’ve marked changes to be included in the next commit.
Committed	Changes are safely stored in the Git database as a snapshot of your work.

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🌿 Git Branching

Branches allow parallel development. You can work on features or bug fixes in isolated branches, then merge them into main when ready.

Pro Tip: Always create a new branch for a feature or fix. Avoid committing directly to main.

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🔗 Git Merging

Merging integrates changes from one branch into another. For example:

git checkout main
git merge feature-branch

After merging, the main branch will include all changes from feature-branch.

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🔧 Common Git Commands

🛠️ Configuration (First-Time Setup)

git config --global user.name "Your Name"
git config --global user.email "you@example.com"
git config --global core.editor "code --wait"

Line-ending configuration:

• macOS/Linux:

  git config --global core.autocrlf input
  

• Windows:

  git config --global core.autocrlf true
  

View/edit global config:

git config --global -e

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🔰 Starting a New Git Project

Initialize a Git repository:

git init

Check repo status:

git status

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📥 Staging & Committing Changes

Stage a specific file:

git add <file-name>

Stage everything:

git add .

Unstage a file:

git reset <file-name>

Commit changes:

git commit -m "Describe your change clearly"

Tip: Use short, meaningful commit messages like "Fix login redirect bug".

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💼 Stashing Temporary Work

Save work-in-progress:

git stash

Restore stashed changes:

git stash apply

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🌱 Working with Branches

Create a new branch:

git branch <branch-name>

Switch to a branch:

git checkout <branch-name>

Create and switch in one command:

git checkout -b <branch-name>

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🧹 Undoing Changes

Revert a specific commit:

git revert <commit-hash>

Reset changes in working directory:

git reset

Be cautious with reset—it alters history. Use revert in collaborative environments.

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🔍 Inspecting History and Diffs

View commit history:

git log

Quick, one-line log:

git log --oneline

Compare file changes:

git diff

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🧬 Rebase (Advanced)

Move a branch onto another base:

git rebase <branch-name>

Use rebase for a cleaner history, but only on your own branches—never rebase shared branches unless you’re sure.

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✅ Summary Cheat Sheet

Action	Command
Initialize repository	git init
Stage changes	git add . or git add <file>
Commit changes	git commit -m "message"
Check status	git status
View history	git log, git log --oneline
Create/switch branch	git checkout -b <branch>
Merge branches	git merge <branch>
Stash work	git stash / git stash apply
Undo commit (safe)	git revert <hash>
Compare changes	git diff

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