如何解码这个PHP混淆？

Question

我尝试使用zen以及其他内容解码此代码，但唯一的问题是我真的不知道如何手动解码这个代码。有人能帮助我吗？

if (!function_exists('f38158721')) {
  function f38158721($fld) {
    $fld1 = dirname($fld);
    $fld = $fld1 . '/scopbin';
    clearstatcache();
    if (!is_dir($fld)) return f38158721($fld1);
      else return $fld;
  }
}

require_once (f38158721(__FILE__) . '/25661563.php');

$REXISTHECAT4FBI = 'FE50E574D754E76AC679F242F450F768FB5DCB77F34DE341 660C280D176E374DE7FB3B090A782B6B68DBC97BEAD93B681C452F25BE26';
f38158721g0666f0acdeed38d4cd9084ade1739498(f38158721f0666f0acdeed38d4cd9084ade1739498(__FILE__));

$REXISTHEDOG4FBI = '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';

$REXISTHECAT4FBI = '94CD76CD371C5A7BC70C186E779C293B9B49BACA5A781A6';

eval(f38158721y0666f0acdeed38d4cd9084ade1739498('MUQyMzM5NThCRDgwODY4MEQ2', $REXISTHEDOG4FBI));