Read data from stdin.
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> Read data from [stdin][@stdlib/streams/node/stdin].
``bash`
npm install @stdlib/process-read-stdin
`javascript`
var stdin = require( '@stdlib/process-read-stdin' );
#### stdin( \[encoding,] clbk )
Reads data from [stdin][@stdlib/streams/node/stdin].
`javascript
function onRead( error, data ) {
if ( error ) {
return console.error( 'Error: %s', error.message );
}
console.log( data.toString() );
// => '...'
}
stdin( onRead );
`
By default, returned data is a [Buffer][buffer]. To return a string of a specified encoding, provide an encoding parameter.
`javascript
function onRead( error, data ) {
if ( error ) {
return console.error( 'Error: %s', error.message );
}
console.log( data );
// => '...'
}
stdin( 'utf8', onRead );
`
When a file's calling Node.js process is running in a [TTY][tty] context (i.e., no [stdin][@stdlib/streams/node/stdin]), data will either be an empty [Buffer][buffer] (no encoding provided) or an empty string (encoding provided).
`javascript
var stream = require( '@stdlib/streams-node-stdin' );
function onRead( error, data ) {
if ( error ) {
return console.error( 'Error: %s', error.message );
}
console.log( data );
// => ''
}
stream.isTTY = true;
stdin( 'utf8', onRead );
`
`javascript
var string2buffer = require( '@stdlib/buffer-from-string' );
var stream = require( '@stdlib/streams-node-stdin' );
var stdin = require( '@stdlib/process-read-stdin' );
function onRead( error, data ) {
if ( error ) {
console.error( 'Error: %s', error.message );
} else {
console.log( data.toString() );
// => 'beep boop'
}
}
// Fake not being in a terminal context:
stream.isTTY = false;
// Provide a callback to consume all data from stdin:
stdin( onRead );
// Push some data to stdin:
stream.push( string2buffer( 'beep' ) );
stream.push( string2buffer( ' ' ) );
stream.push( string2buffer( 'boop' ) );
// End the stream:
stream.push( null );
`
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
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---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/process-read-stdin/tree/deno
[deno-readme]: https://github.com/stdlib-js/process-read-stdin/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/process-read-stdin/tree/umd
[umd-readme]: https://github.com/stdlib-js/process-read-stdin/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/process-read-stdin/tree/esm
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[buffer]: https://nodejs.org/api/buffer.html
[tty]: https://nodejs.org/api/tty.html#tty_tty
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