gistfile1.php

<?php
// PHP version < 5.3
function compareFileName($a, $b, $keyToSortBy) {
  return strnatcmp($a[$keyToSortBy], $b[$keyToSortBy]);
}

usort($arrayThatIsPopulated, 'compareFileName');

// PHP version >= 5.3
usort($arrayThatIsPopulated, function($a, $b, $keyToSortBy) { 
	return strnatcmp($a[$keyToSortBy], $b[$keyToSortBy]);
});