Lifo

A Linux-like operating system that runs natively in the browser. Not a VM, not an emulator -- a reimagination of Unix where the browser runtime is the kernel and browser APIs are the system calls.

┌──────────────────────────────────────────────────┐
│                  Terminal UI                      │  xterm.js + Tokyo Night theme
├──────────────────────────────────────────────────┤
│                    Shell                          │  bash-like interpreter
├──────────────────────────────────────────────────┤
│            Command Registry / $PATH              │  ES module command map
├───────────┬────────────┬─────────────────────────┤
│ Coreutils │ Net Cmds   │ User Packages           │  each cmd = async function
├───────────┴────────────┴─────────────────────────┤
│          Node.js Compatibility Layer             │  thin wrappers over OS APIs
├──────────────────────────────────────────────────┤
│           Virtual Filesystem (VFS)               │  in-memory + IndexedDB persistence
├──────────────────────────────────────────────────┤
│              Kernel API Layer                    │  unified browser API wrappers
├──────────────────────────────────────────────────┤
│               Browser APIs                       │  fetch, streams, OPFS, etc.
└──────────────────────────────────────────────────┘

Getting Started

pnpm install
pnpm dev

Open http://localhost:5173 in a modern browser. You'll be greeted with a fully functional terminal.

pnpm build        # Production build
pnpm test         # Run test suite
pnpm typecheck    # Type check without emitting

What's Inside

Kernel

• Virtual Filesystem (VFS) -- synchronous in-memory INode tree with full POSIX-like semantics (read, write, stat, mkdir, symlinks, hard links, permissions)
• Virtual Providers -- /proc exposes system info (uptime, meminfo, cpuinfo, version) and /dev provides device files (null, zero, random, urandom)
• Persistence -- IndexedDB-backed filesystem persistence with serialization/deserialization of the entire INode tree

Shell

A bash-like shell with:

• Full lexer/parser/interpreter pipeline producing an AST
• Pipes (ls | grep foo | wc -l), redirects (>, >>, <, 2>, &>)
• Logical operators (&&, ||), sequences (;), background (&)
• Variable expansion ($VAR, ${VAR:-default}), command substitution ($(...))
• Glob expansion (*.txt, **/*.js), tilde expansion (~), brace expansion ({a,b,c})
• Tab completion for commands, files, and directories
• Command history with reverse search
• Job control (Ctrl+C, fg, bg, jobs)
• Builtins: cd, pwd, export, alias, source, read, test, echo, and more

60+ Commands

| Category | Commands | |---|---| | Filesystem | ls, cat, cp, mv, rm, mkdir, rmdir, touch, ln, stat, find, tree, du, df, chmod, file, basename, dirname, realpath, mktemp | | Text | grep, sed, awk, head, tail, sort, uniq, wc, cut, tr, diff, nl, rev | | I/O | printf, tee, xargs, yes | | Network | curl, wget, ping, dig | | System | ps, top, kill, env, uname, whoami, hostname, uptime, free, date, cal, bc, sleep, watch, which, man, help | | Archive | tar, gzip, gunzip, zip, unzip | | Runtime | node (run JS with Node.js compat layer), pkg (package manager) |

Node.js Compatibility Layer

Run JavaScript files with node script.js or node -e "code". The compatibility layer maps 15 Node.js standard library modules to browser APIs:

fs, path, events, buffer, util, os, process, http, child_process, stream, url, timers, crypto, console

Package Manager

pkg install <url>    # Install a package from URL
pkg remove <name>    # Uninstall a package
pkg list             # List installed packages
pkg info <name>      # Show package details

Filesystem Hierarchy

/
├── home/user/          # User home directory ($HOME)
├── tmp/                # Temporary files (in-memory)
├── etc/                # System configuration
├── var/log/            # System logs
├── usr/bin/            # Installed package binaries
├── proc/               # Virtual: system info (cpuinfo, meminfo, uptime)
├── dev/                # Virtual: devices (null, zero, random, urandom)
└── bin/                # Core commands

Tech Stack

• TypeScript (strict mode, ESM throughout)
• Vite for builds
• xterm.js + WebGL addon for terminal rendering
• Vitest for testing
• Target: Chrome 110+, Firefox 110+, Safari 16.4+

Project Structure

src/
├── main.ts              # Boot sequence
├── kernel/              # VFS, persistence, virtual providers
├── shell/               # Lexer, parser, interpreter, expander, completer
├── commands/            # All 60+ commands organized by category
├── node-compat/         # Node.js standard library shims
├── pkg/                 # Package manager
├── terminal/            # xterm.js wrapper
└── utils/               # Path, args, glob, colors, encoding, archive
tests/                   # Mirrors src/ structure with full coverage

License

MIT