Run any command in background from PHP

BackgroundProcess.php

<?php

namespace _\sys;

use RuntimeException;

class BackgroundProcess
{
	/**
	 * Theory:
	 * - http://stackoverflow.com/a/7149229/335304
	 * - http://ua1.php.net/shell_exec#59898
	 * - http://nsaunders.wordpress.com/2007/01/12/running-a-background-process-in-php/
	 * @param $cmd
	 * @param int $nicenessAddition
	 * @return array
	 * @throws \RuntimeException
	 */
	static function run($cmd, $nicenessAddition = 0)
	{
		$s = '';
		if ($nicenessAddition)
			$s .= 'nice -n ' . $nicenessAddition . ' ';
		$s .= $cmd . ' &';

		$p = proc_open($s, array(), $pipes);
		if (!is_resource($p))
			throw new RuntimeException('Cannot start command ' . $cmd . ' in background with using: ' . $s);
		proc_close($p);
	}
}