code: function run(cmd, args, options, done) {
    if (typeof options === 'function') {
      done = options;
      options = undefined;
    }
  
    var executed = false;
    var ch = spawn(cmd, args, options);
    var stdout = '';
    var stderr = '';
  
    ch.stdout.on('data', function(d) {
      stdout += d.toString();
    });
  
    ch.stderr.on('data', function(d) {
      stderr += d.toString();
    });
  
    ch.on('error', function(err) {
      if (executed) return;
      executed = true;
      done(new Error(err));
    });
  
    ch.on('close', function(code) {
      if (executed) return;
      executed = true;
  
      if (stderr) {
        return done(new Error(stderr));
      }
  
      done(null, stdout, code);
    });
  }
docs: Spawn a binary and read its stdout.
  @param  {String} cmd The name of the binary to spawn.
  @param  {String[]} args The arguments for the binary.
  @param  {Object} [options] Optional option for the spawn function.
  @param  {Function} done(err, stdout)