nodejs spawn shell process (ps aux) and filter

gistfile1.js

  var run_cmd = function(cmd, args, callBack) {
    var spawn = require('child_process').spawn;
    var child = spawn(cmd, args);
    var resp = "";

    child.stdout.on('data', function (buffer) { resp += buffer.toString() });
    child.stdout.on('end', function() { callBack (resp) });
  }

  var check_ps_aux = function(service) {

    run_cmd( "ps", ["aux"], function(output) {
      var output_lines = output.split(/\r?\n/);
      var filtered = output_lines.filter(function(x){
        var regex = new RegExp(service.ps_search, 'i');
        return regex.test(x);
      });

      // update data
      service.is_running = filtered.length > 0 ? true : false;

    });
  }