Show HN: A Unix environment in a single HTML file (420 KB)

Source: Hacker News

Overview

A Unix environment in one HTML file.

• Shell, filesystem, git, npm, vi, and 200+ commands.
• ~420 KB gzipped. No server. Runs in your browser right now.

shiro.computer

user@shiro:~$ npm init -y
Wrote to /home/user/package.json

user@shiro:~$ npm install left-pad
added 1 package

user@shiro:~$ echo 'const lp = require("left-pad"); console.log(lp("hello HN", 30, "."))' > app.js

user@shiro:~$ node app.js
......................hello HN

user@shiro:~$ git init && git add . && git commit -m "shipped from a browser tab"
Initialized empty Git repository in /home/user
[main (root-commit) a1b2c3d] shipped from a browser tab
 3 files changed, 17 insertions(+)

user@shiro:~$ ▮

A static HTML file that boots into a Unix shell. The filesystem is IndexedDB. Commands are JavaScript. Files survive page reloads. Everything runs client‑side — the page works offline with no server at all.

Build and interact with apps

Write a counter, serve it, click buttons from the shell, upgrade to a grapher, commit with git.

Interact → counter → serve → page commands → upgrade → commit

Serve an app, use page to click and read DOM elements, then commit.

Real git, no server

init, add, commit, diff — all running client‑side via isomorphic‑git.

Snapshot as a GIF

Capture the entire filesystem into a GIF. Drag it to another instance to restore.

Seed GIF → snapshot → drag → restore

source → target (illustrative)

How it works

Filesystem

IndexedDB with a POSIX‑like API: stat, readdir, readFile, writeFile, mkdir, symlink, chmod, glob. Files persist across reloads.

Shell

Supports pipes, redirects, $variables, &&, ||, quoting, heredocs—enough POSIX features for real scripting.

Packages

Real npm tarballs from the registry. node runs JavaScript files. esbuild bundles TypeScript. require() resolves node_modules.

One file

Single self‑contained HTML. All JS/CSS inlined by the build. ~420 KB gzipped. Deploy anywhere — GitHub Pages, S3, or open it locally.