yld.js

process.stdin.setEncoding('utf8');

// becomes readable on every [enter] keystroke
process.stdin.on('readable', function(chunk) {
  var chunk = process.stdin.read();
  if (chunk !== null) {
    console.log(chunk
      .split('')
      .map(function(c) {
        return String.fromCharCode(c.charCodeAt(0)-1);
      }).join(''));
  }
});