Run php script in background with symfony process component

background_php_job.php

<?php

require 'vendor/autoload.php';

use Symfony\Component\Process\Process;
use Symfony\Component\Process\ProcessBuilder;

$builder = new ProcessBuilder();
$builder->setPrefix('/usr/local/bin/php');
$cmd = $builder->setArguments(['/Users/tuncay/longRunningTask.php'])
    ->getProcess()
    ->getCommandLine();

$process = new Process($cmd . '  > /dev/null 2>&1 &');
$process->run();