Simple non-blocking command runner

RunBackground.php

<?php
/**
 * Simple non-blocking command runner
 *
 * Class RunBackground
 */
class RunBackground {

    /**
     * Running command without waiting for it to complete
     *
     * @param string $cmd
     * @param string $inDir
     */
    public static function command ($cmd, $inDir = '.') {
        switch(static::detectOS()) {
            case 'nix':
                shell_exec("cd $inDir && $cmd > /dev/null 2>/dev/null &");
                break;

            case 'win':
                pclose(popen("cd $inDir && start /B $cmd", "r"));
                break;
        }
    }

    /**
     * Easiest OS detection ever
     *
     * @return string
     */
    protected static function detectOS () {
        return is_writeable("/dev/null") ? "nix" : "win";
    }
}