process.stdin, test

a.js

function f(s) {
  return s.split('').map(function (a) {
    return ('00' + a.charCodeAt(0).toString(16)).slice(-2);
  }).join(' ');
}
process.stdin.setEncoding('utf8');
process.stdin.on('readable', function () {
  var a = process.stdin.read();
  if (a !== null) {
    console.log('> ', a.replace(/\n/, ''));
    console.log('| ', f(a));
  }
});

b.js

function f(s) {
  return s.split('').map(function (a) {
    return ('00' + a.charCodeAt(0).toString(16)).slice(-2);
  }).join(' ');
}
process.stdin.setEncoding('utf8');
process.stdin.on('data', function (a) {
  if (a !== null) {
    console.log('> ', a.replace(/\n/, ''));
    console.log('| ', f(a));
  }
});