Recursive Find File

Recursively looks for a file in directories in the current a top-level from the calling script. Will return false if the file cannot be found.
<?php

function find_file($file, $prev_path = '')
{
 $new_path = ($prev_path == '') ? dirname(__FILE__) : dirname($prev_path);
 
 if ($prev_path == $new_path)
  return false;
 
 $full_path = $new_path . DIRECTORY_SEPARATOR . $file; 
 
 return (file_exists($full_path)) ? $full_path : find_file($file, $new_path);
}

?>

Usage

$file = find_file('file_in_a_higher_directory_but_dont_know_where.php');

if ($file)
include($file);
else
echo "File Not Found!";