function Sort_Directory_Files_By_Last_Modified($dir, $sort_type = 'descending', $date_format = "F d Y H:i:s.")
{
$files = scandir($dir);

$array = array();

foreach($files as $file)
{
	if($file != '.' && $file != '..')
	{
		$now = time();
		$last_modified = filemtime($dir.$file);

		$time_passed_array = array();

		$diff = $now - $last_modified;

		$days = floor($diff / (3600 * 24));

		if($days)
		{
		$time_passed_array['days'] = $days;
		}

		$diff = $diff - ($days * 3600 * 24);

		$hours = floor($diff / 3600);

		if($hours)
		{
		$time_passed_array['hours'] = $hours;
		}

		$diff = $diff - (3600 * $hours);

		$minutes = floor($diff / 60);

		if($minutes)
		{
		$time_passed_array['minutes'] = $minutes;
		}

		$seconds = $diff - ($minutes * 60);

		$time_passed_array['seconds'] = $seconds;

	$array[] = array('file'         => $file,
		             'timestamp'    => $last_modified,
		             'date'         => date ($date_format, $last_modified),
		             'time_passed'  => $time_passed_array);
	}
}

usort($array, create_function('$a, $b', 'return strcmp($a["timestamp"], $b["timestamp"]);'));

if($sort_type == 'descending')
{
krsort($array);
}

return array($array, $sort_type);
}

//Example of usage:

$dir  = '/home/public_html/my_directory/';

$array = Sort_Directory_Files_By_Last_Modified($dir);

// Info Array
$info = $array[0];

// Sort Type
$sort_type = $array[1];

echo '<h3>'.$dir.'</h3>';

echo 'Order by: Last Modified ('.$sort_type.')<br>';

foreach($info as $key => $detail)
{
	echo '<h4>'.$detail['file'].'</h4>';

	echo 'Last Modified: '.$detail['date'].'<br>';

	$time_passed = '';

	foreach($detail['time_passed'] as $type => $value)
	{
	$time_passed .= $value." ".$type.", ";
	}

	$time_passed = "<span>".rtrim($time_passed, ", ")."</span> ago";

	echo $time_passed."nn";

}

function Sort_Directory_Files_By_Last_Modified($dir, $sort_type = 'descending', $date_format = "F d Y H:i:s.")
{
$files = scandir($dir);

$array = array();

foreach($files as $file)
{
	if($file != '.' && $file != '..')
	{
		$now = time();
		$last_modified = filemtime($dir.$file);

		$time_passed_array = array();

		$diff = $now - $last_modified;

		$days = floor($diff / (3600 * 24));

		if($days)
		{
		$time_passed_array['days'] = $days;
		}

		$diff = $diff - ($days * 3600 * 24);

		$hours = floor($diff / 3600);

		if($hours)
		{
		$time_passed_array['hours'] = $hours;
		}

		$diff = $diff - (3600 * $hours);

		$minutes = floor($diff / 60);

		if($minutes)
		{
		$time_passed_array['minutes'] = $minutes;
		}

		$seconds = $diff - ($minutes * 60);

		$time_passed_array['seconds'] = $seconds;

	$array[] = array('file'         => $file,
		             'timestamp'    => $last_modified,
		             'date'         => date ($date_format, $last_modified),
		             'time_passed'  => $time_passed_array);
	}
}

usort($array, create_function('$a, $b', 'return strcmp($a["timestamp"], $b["timestamp"]);'));

if($sort_type == 'descending')
{
krsort($array);
}

return array($array, $sort_type);
}

http://www.bitrepository.com/web-programming/php/sort-files-by-filemtime.html

This is a function that selects files from a directory and orders them by the last time they were changed, in ascending or descending order. The snippet also calculates how much time passed since the file’s content was changed.

Sort files from directory & order them by filemtime()

sort, files, directory

PHP