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

Every Git repo has a dirty little secret. A hidden folder. A place where Git stores everything.

It's called .git. And today, we're breaking in.

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The Secret Room

Run git init and Git creates a .git folder. This is Git's brain — delete it, and your repo forgets everything.

ls -la .git

Output:

HEAD
config
objects/
refs/
hooks/

Let's see what's inside.

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Git Objects — The Building Blocks

Git stores everything as objects. Three types:

Every object gets a SHA-1 hash — a unique 40-character ID. Change one byte, the hash changes completely. That's how Git ensures nothing is tampered with.

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What Happens When You Commit?

Step 1: git add

Git takes your file, compresses it, and stores it as a blob in .git/objects/.

git add hello.txt

Peek inside:

find .git/objects -type f

Output:

.git/objects/e9/65047ad7c7f9b8e...

That's your file — hashed and stored.

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Step 2: git commit

Git creates a tree (directory snapshot) and a commit object pointing to it.

git commit -m "Add hello"

Now check the log with object details:

git log --oneline

Output:

3a7b2c1 Add hello

That 3a7b2c1? It's the commit's hash. Git's way of saying: "This exact snapshot, forever."

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Inspect Any Object

Want to see what's inside an object? Use cat-file:

git cat-file -t 3a7b2c1    # Type
git cat-file -p 3a7b2c1    # Content

Output:

commit

tree 5d8f2a...
author Tanish <tanish@example.com> 1706700000 +0530
committer Tanish <tanish@example.com> 1706700000 +0530

Add hello

Git just showed you its diary.

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The Mental Model

Commit → Tree → Blobs
   ↓
Points to parent commit (history chain)

Every commit knows its parent. That's how git log traces history. That's how branches work. That's how Git never loses anything.

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Quick Peek Commands

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The .git folder isn't scary. It's just blobs, trees, and commits — all hashed, all connected.

Now you know where Git hides the bodies. 💀

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