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bun.sh/docs/guides/process/stdin.mdx
2025-11-21 14:06:19 -08:00

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---
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](/runtime/utils) for more useful utilities.