Little search and replace trouble

[strago]

$file=str_replace("{title2}",$line['title'],$file);
$file['title2'] = trim(preg_replace('/[^\w\d]+/', ' ', $file['title2']));
$file['title2'] = str_replace(' ', '-', $file['title2']);

 

The first line does what it should do, have {title2} in the template generate the page title. The next two lines don't do the replacing.