# Run TypeScript directly
bun run index.ts

# Install packages
bun install

# Run package.json script
bun run dev

# Execute package binary
bunx cowsay "Hello"

# Run tests
bun test

# Build for production
bun build ./index.ts --outdir ./dist

# Bundle analysis for LLMs (v1.3.8+)
bun build ./index.ts --metafile-md --outdir ./dist

Bun.serve({
  port: 3000,
  fetch(req) {
    const url = new URL(req.url);
    if (url.pathname === "/api/data") {
      return Response.json({ ok: true });
    }
    return new Response("Not Found", { status: 404 });
  },
});

// Read
const content = await Bun.file("data.txt").text();

// Write
await Bun.write("output.txt", "Hello World");

// JSON
const config = await Bun.file("config.json").json();

import { Database } from "bun:sqlite";

const db = new Database("app.db");
db.run("CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY, name TEXT)");

const insert = db.prepare("INSERT INTO users (name) VALUES (?)");
insert.run("Alice");

const users = db.query("SELECT * FROM users").all();

Bun.serve({
  fetch(req, server) {
    if (server.upgrade(req)) return;
    return new Response("Upgrade failed", { status: 400 });
  },
  websocket: {
    message(ws, message) {
      ws.send(`Echo: ${message}`);
    },
  },
});

import { $ } from "bun";

// Simple command
const files = await $`ls -la`.text();

// With variables (auto-escaped)
const name = "my file.txt";
await $`cat ${name}`;

// Piping
await $`cat data.csv | grep "pattern" | wc -l`;

import { s3 } from "bun";

// Upload
await s3.file("uploads/doc.pdf").write(data);

// Download
const content = await s3.file("uploads/doc.pdf").text();

// Presigned URL
const url = s3.presign("uploads/doc.pdf", { expiresIn: 3600 });

import { redis } from "bun";

await redis.set("key", "value");
const value = await redis.get("key");
await redis.expire("key", 3600);

import { expect, test, describe } from "bun:test";

describe("math", () => {
  test("2 + 2 = 4", () => {
    expect(2 + 2).toBe(4);
  });
});

[run]
watch = true

[install]
registry = "https://registry.npmjs.org"

[test]
coverage = true

# .env files loaded automatically
DATABASE_URL=postgres://localhost/mydb

// Access
Bun.env.DATABASE_URL;
process.env.DATABASE_URL;
import.meta.env.DATABASE_URL;