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For CLI tools, it’s often useful to read from stdin. In Bun, the console object is an AsyncIterable that yields lines from stdin.
https://mintcdn.com/bun-1dd33a4e/Hq64iapoQXHbYMEN/icons/typescript.svg?fit=max&auto=format&n=Hq64iapoQXHbYMEN&q=85&s=c6cceedec8f82d2cc803d7c6ec82b240index.ts
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.
terminal
bun run index.ts

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.
https://mintcdn.com/bun-1dd33a4e/Hq64iapoQXHbYMEN/icons/typescript.svg?fit=max&auto=format&n=Hq64iapoQXHbYMEN&q=85&s=c6cceedec8f82d2cc803d7c6ec82b240stdin.ts
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.
terminal
echo "hello" | bun run stdin.ts

Chunk: hello
See Docs > API > Utils for more useful utilities.