code: function getPsInfo(param, callback) { 
  	if (process.platform === 'windows') return;
  	var pid = param.pid;
  	var cmd = "ps auxw | grep " + pid + " | grep -v 'grep'";
  	//var cmd = "ps auxw | grep -E '.+?\\s+" + pid + "\\s+'"  ;
  	exec(cmd, function(err, output) {
  		if (!!err) {
  			if (err.code === 1) {
  				console.log('the content is null!');
  			} else {
  				console.error('getPsInfo failed! ' + err.stack);
  			}
  			callback(err, null);
  			return;
  		} 
      format(param, output, callback);
  	});
  }
docs: get the process information by command 'ps auxw | grep serverId | grep pid'
  
  @param {Object} param
  @param {Function} callback
  @api public