Git Working Directory, Staging Area and Repository Explained

Most Git confusion disappears once you understand three places: the working directory, the staging area and the repository. This lesson explains them with diagrams, git status output and the commands that move changes between them.

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🧩 The Three Areas of Git

Every Git project has three areas. Understanding them makes every other Git command easier.

Area	Also called	What it holds
Working directory	Working tree	The files you see and edit in your folder
Staging area	Index	The changes you have selected for the next commit
Repository	Local repo, .git	Every commit, saved permanently

┌───────────────────┐  git add   ┌──────────────┐  git commit  ┌──────────────┐
│ Working directory │ ─────────▶ │ Staging area │ ───────────▶ │  Repository  │
│  (edit files)     │ ◀───────── │   (index)    │              │   (.git)     │
└───────────────────┘ git restore└──────────────┘              └──────────────┘
                        --staged

Analogy: packing for a trip. The working directory is your room full of clothes, the staging area is the open suitcase where you put only what you want to take, and a commit closes the suitcase and labels it with the date.

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🚦 The Four States of a File

State	Meaning	How it gets there
Untracked	New file Git has never seen	You create a file
Unmodified	Tracked and identical to the last commit	After a commit
Modified	Tracked, changed, not staged	You edit a tracked file
Staged	Change selected for the next commit	git add

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🔎 Reading git status

git status

On branch main
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	modified:   README.md

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   test-plan.txt

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	login.spec.ts

Three sections, three areas: staged (green), modified but not staged (red), and untracked.

The short format

git status -s

M  README.md
 M test-plan.txt
?? login.spec.ts

Code	Meaning
M in the left column	Modified and staged
M in the right column	Modified, not staged
MM	Staged, then modified again
A	New file, staged
D	Deleted
??	Untracked

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🔬 See the Differences in Each Area

git diff            # working directory vs staging area (unstaged changes)
git diff --staged   # staging area vs last commit (what will be committed)
git diff HEAD       # working directory vs last commit (everything)

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🔁 Moving Changes Between Areas

Goal	Command
Stage a change	git add file
Unstage a change (keep it in the file)	git restore --staged file
Discard unstaged changes in a file	git restore file (cannot be undone)
Stop tracking a file but keep it on disk	git rm --cached file
Delete a tracked file and stage the deletion	git rm file
Rename or move a tracked file	git mv old.txt new.txt

More ways to undo things, including commits, are in Undo Changes.

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🎯 Why the Staging Area Is Useful

The staging area lets you build clean, focused commits even when you changed many things at once:

# You fixed a bug AND reformatted some files. Commit them separately:
git add src/checkout.ts
git commit -m "Fix rounding of tax on checkout"

git add .
git commit -m "Format test files with Prettier"

With git add -p you can even stage parts of a file: Git shows each changed block (hunk) and asks y (stage), n (skip), s (split) or q (quit).

Small, focused commits make history readable, code review easier and bugs easier to find with tools like git bisect.

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📝 Assignment

In your git-practice repository:

1. Create a new file, modify a tracked file, and stage only the modified one. Run git status and git status -s and identify each state.
2. Run git diff, git diff --staged and git diff HEAD and describe what each shows.
3. Stage a file, then unstage it with git restore --staged.
4. Make a change you do not want and discard it with git restore.
5. Rename a file with git mv and commit the rename.
6. Bonus: change two unrelated lines in one file and commit them separately using git add -p.

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❓ FAQ

🤔 What is the staging area in Git?

A middle step between your files and the repository where you collect the exact changes for the next commit. It is also called the index.

🤔 What is the difference between git diff and git diff –staged?

git diff shows changes not yet staged. git diff --staged shows staged changes that will go into the next commit.

🤔 How do I unstage a file in Git?

git restore --staged file moves the change out of the staging area but keeps your edits in the file.

🤔 What does ?? mean in git status -s?

The file is untracked: Git has never been told to track it.

🤔 How do I stop tracking a file without deleting it?

git rm --cached file, then add it to .gitignore so it is not added again.

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🎯 Next Steps

• 📜 View History and Changes: git log, show and diff
• 🙈 .gitignore: Ignore Files the Right Way
• 📘 Git and GitHub Tutorial: full course