exec.php

<?php

require 'library/MainFunction.php';

echo '<link href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet">';
echo '<link rel="stylesheet" href="assets/style.css">';
echo '<div class="contentBox">';
set_time_limit(0);

$c = _GET('command', 'unknow');

if ($c == 'unknow') {
    echo '';
    exit;
}

$handle = popen($c, "r");

if (ob_get_level() == 0) {
    ob_start();
}

while (!feof($handle)) {

    $buffer = fgets($handle);
    $buffer = trim(htmlspecialchars($buffer));

    echo $buffer . "<br />";
    echo str_pad('', 4096);

    ob_flush();
    flush();
    sleep(0.001);
}

pclose($handle);
ob_end_flush();
echo '</div>';