bun-types/docs/guides/process/stdin.mdx

Type definitions and documentation for Bun, an incredibly fast JavaScript runtime

---
title: Read from stdin
sidebarTitle: Read from stdin
mode: center
---

For CLI tools, it's often useful to read from `stdin`. In Bun, the `console` object is an `AsyncIterable` that yields lines from `stdin`.

```ts index.ts icon="/icons/typescript.svg"
const prompt = "Type something: ";
process.stdout.write(prompt);
for await (const line of console) {
  console.log(`You typed: ${line}`);
  process.stdout.write(prompt);
}
```

---

Running this file results in a never-ending interactive prompt that echoes whatever the user types.

```sh terminal icon="terminal"
bun run index.ts
```

```txt
Type something: hello
You typed: hello
Type something: hello again
You typed: hello again
```

---

Bun also exposes stdin as a `BunFile` via `Bun.stdin`. This is useful for incrementally reading large inputs that are piped into the `bun` process.

There is no guarantee that the chunks will be split line-by-line.

```ts stdin.ts icon="/icons/typescript.svg"
for await (const chunk of Bun.stdin.stream()) {
  // chunk is Uint8Array
  // this converts it to text (assumes ASCII encoding)
  const chunkText = Buffer.from(chunk).toString();
  console.log(`Chunk: ${chunkText}`);
}
```

---

This will print the input that is piped into the `bun` process.

```sh terminal icon="terminal"
echo "hello" | bun run stdin.ts
```

```txt
Chunk: hello
```

---

See [Docs > API > Utils](/docs/runtime/utils) for more useful utilities.