Find string in all included files in PHP

Some times when debugging we find some variables or string, but when tons of php code is included its big problem. Here's how I search string or variable in all included files.

$file_included = get_included_files();

foreach($file_included as $val) {
    if(preg_match('/YOUR STRING HERE/',file_get_contents($val))){  
       echo $val.'
';
    }

}

You simply need to include that on the footer of your page