lib/prince.php
private function cmdlineArgEscape2($argStr)
    {
        //chr(92) is character backslash ( \ ).
        $len = strlen($argStr);

        $numTrailingSlashes = 0;
        for($i = ($len - 1); $i  >= 0; $i--)
        {
            if($argStr[$i] == chr(92))
            {
                $numTrailingSlashes += 1;
            }
            else
            {
                break;
            }
        }

        while($numTrailingSlashes > 0)
        {
            $argStr .= chr(92);
            $numTrailingSlashes -= 1;
        }

        return $argStr;
    }
private function cmdlineArgEscape2($argStr)
    {
        //chr(92) is character backslash ( \ ).
        $len = strlen($argStr);

        $numTrailingSlashes = 0;
        for($i = ($len - 1); $i  >= 0; $i--)
        {
            if($argStr[$i] == chr(92))
            {
                $numTrailingSlashes += 1;
            }
            else
            {
                break;
            }
        }

        while($numTrailingSlashes > 0)
        {
            $argStr .= chr(92);
            $numTrailingSlashes -= 1;
        }

        return $argStr;
    }
Double the number of trailing backslash(es):      n*trailing backslash => (2*n)*trailing backslash.