Listing 30.15. Konwersja dokumentów XLS do formatu TXT
$files = glob('dane-xls/*.xls');
foreach ($files as $f) {
    $nf = newfilename($f, '.txt');
    $parsed = parse_xls($f);
    $txt = array2txt($parsed);
    file_put_contents($nf, $txt);
}
