Inside Git: How It Works and the Role of the .git Folder

What is .git Folder?

When you run git init, Git creates a hidden .git folder.

This folder stores all history, commits, and data.
If it’s deleted → your repo is gone.

.git = Git’s database

Inside .git (Simplified)

.git/
│
├── objects/     → Stores all file data (blobs, trees, commits)
├── refs/        → Branch pointers
├── HEAD         → Current branch
├── index        → Staging area
├── config       → Repo settings

Mental Model

.git = Database where Git stores everythin

1. Blob (File Content)

A blob stores:

✅ Only file data
❌ No filename

Example:

hello.txt → "Hi World"

Git saves:

Blob = "Hi World"

If 2 files have same content → Git stores only ONE blob (saves space )

---

🔹 2. Tree (Folder Structure)

A tree stores:

✅ Folder info
✅ File names
✅ Links to blobs

Example:

project/
 ├─ app.js
 └─ index.html

Tree connects:

Tree
 ├── app.js → Blob
 └── index.html → Blob

Think of Tree = Folder snapshot 📁

---

🔹 3. Commit (Snapshot Record 📸)

A commit stores:

✅ Pointer to Tree
✅ Author
✅ Date
✅ Message
✅ Parent commit

Commit
   ↓
  Tree
   ↓
 Blobs

Each commit = Full snapshot of project

How Git Tracks Changes

Git doesn’t save only differences.

It saves snapshots of files.
Same files = reused (no extra space).

So Git is fast and efficient.

What Happens in git add?

git add file.txt

✔ Creates a blob
✔ Puts it in staging area (index)

Files → Staging Area

What Happens in git commit?

git commit -m "msg"

✔ Creates tree
✔ Creates commit
✔ Moves branch forward

Staging → Commit → Branch

How Git Uses Hashes

Every object has a unique hash.

👉 If data changes → hash changes
👉 Keeps Git secure and reliable 🔐

Summary

• .git = main storage

• Blob = file

• Tree = folder

• Commit = snapshot

• add = prepare

• commit = save