<?php
function bbCode($txt)
{
   $ret = strip_tags($txt);
   $ret = preg_replace('#\[bkz\](.+)\[\/bkz\]#iUs', '(bkz:&nbsp;<a href="/blaaa.php?kelime=$1">$1</a>)', $ret);
   $ret = preg_replace('#\[link\=(.+)\](.+)\[\/link\]#iUs', '<a href="$1">$2</a>', $ret);
   $ret = preg_replace('#\[img\](.+)\[\/img\]#iUs', '<img src="$1" alt="Image" />', $ret); 

   return $ret;
}

$ek = bbCode('[bkz]selam[/bkz]');

echo $ek;
 
?>