Git — The Time Machine for Code

Interactive

Build a Commit Graph

Click the buttons to simulate Git operations and watch the commit DAG grow in real time.

Try It

Simulated Terminal

Type Git commands and see simulated output. Try: init, status, add, commit, log, branch, checkout, diff, stash, remote.

~/my-project — bash

Welcome to the Git simulator. Type a git command to begin.

Try: git init, git status, git add, git commit -m "msg", git log

~/my-project $

Under the Hood

Git Object Model

Everything in Git is a content-addressable object stored as a SHA-1 hash. Four object types form the entire data model.

📄

Blob

Raw file contents. No filename, no metadata — just bytes. Identical files across branches share the same blob.

📁

Tree

A directory listing. Maps filenames to blob hashes (or other trees for subdirectories). This is your snapshot's filesystem.

💾

Commit

Points to a tree + parent commit(s). Stores author, timestamp, message. The chain of commits forms the DAG.

🏷️

Tag

A named reference to a commit with optional GPG signature. Annotated tags are full objects; lightweight tags are just refs.

Quick Ref

Cheat Sheet

Setup & Init

git initNew repo

git clone <url>Copy remote

git config --global user.nameSet identity

Stage & Snapshot

git add .Stage all

git commit -m "msg"Save snapshot

git stashShelve changes

git reset HEAD~1Undo last commit

Branch & Merge

git branch <name>Create branch

git switch <name>Switch branch

git merge <branch>Merge in

git rebase <base>Replay on top

Inspect & Compare

git log --oneline --graphVisual history

git diffUnstaged changes

git blame <file>Line-by-line author

git reflogEvery HEAD move

Share & Sync

git push origin mainUpload commits

git pull --rebaseFetch + rebase

git fetch --allDownload refs

git remote -vList remotes

Undo & Recover

git revert <sha>Safe undo commit

git cherry-pick <sha>Copy one commit

git bisect startBinary search bug

git clean -fdRemove untracked

The Time Machine
for Code