truncRandom.js

var fs = require('fs'),
    Trunc = require('truncating-stream'),
    truncStream = new Trunc({limit: 10}),
    readStream = fs.createReadStream('/dev/random')

readStream.on('end', function() { console.log('readStream ended') })
readStream.on('close', function() { console.log('readStream closed') })

readStream.pipe(truncStream).pipe(process.stdout)

setTimeout(function() { console.log('all done - did we close?') }, 10000)