如何绕过php过滤器

Question

我想查看flag.txt 这是其中一些单词和符号被屏蔽的代码，你们能帮我绕过它吗？我找不到绕过它的方法。

error_reporting(0);
if (isset($_GET['print'])) {
  if (!empty($_GET['print'])){
    $printValue= strtolower($_GET['print']);
    $blocked = array("cat", "more" ,"readfile", "fopen", "file_get_contents", "file", "SplFileObject" );
    $special_block= "nc";
    $$special_block= "../flag.txt";
    foreach ($blocked as $value) {
      if (strpos($printValue, $value) || preg_match('/\bsystem|\bexec|\bbin2hex|\bassert|\bpassthru|\bshell_exec|\bescapeshellcmd| \bescapeshellarg|\bpcntl_exec|\busort|\bpopen|\bflag\.txt|\bspecial_block|\brequire|\bscandir|\binclude|\bhex2bin|\$[a-zA-Z]|[#!%^&*_+=\-,\.:`|<>?~\\\\]/i', $printValue)) {
        $printValue="";
        echo "<script>alert('Bad character/word ditected!');</script>";
        break;
      }
    }
  eval($printValue . ";");
  } 
}```