code: function exec(command
  	, options = { encoding:'binary' }
  	, callback = (err, stdout, stderr) =>	{
  												if (err) {
  													console.log( ENCODING ? iconv.decode(new Buffer(stderr, 'binary'), ENCODING) : stderr );
  													console.log('------------------------------------------------------');
  													console.log('Execute command failed:');
  													console.log(command);
  													console.log('------------------------------------------------------');
  												}else{
  													console.log( ENCODING ? iconv.decode(new Buffer(stdout, 'binary'), ENCODING) : stdout );
  												}
  											}
  	) {
  	return (typeof options == 'function') ?
  			child_process.exec(command, { encoding:'binary' },  options) :
  			child_process.exec(command, options,  callback);
  }
docs: 异步执行