filectime

This method gets all the files in a directory, and echoes them in the order of the date they were added (by ftp or whatever).
<?PHP
function dirList ($directory, $sortOrder){
 //Get each file and add its details to two arrays
 $results = array();
 $handler = opendir($directory);
 while ($file = readdir($handler)) { 
 if ($file != '.' && $file != '..' && $file != "robots.txt" && $file != ".htaccess"){
 $currentModified = filectime($directory."/".$file);
 $file_names[] = $file;
 $file_dates[] = $currentModified;
 } 
 }
 closedir($handler);
 //Sort the date array by preferred order
 if ($sortOrder == "newestFirst"){
 arsort($file_dates);
 }else{
 asort($file_dates);
 }
 
 //Match file_names array to file_dates array
 $file_names_Array = array_keys($file_dates);
 foreach ($file_names_Array as $idx => $name) $name=$file_names[$name];
 $file_dates = array_merge($file_dates);
 
 $i = 0;
 //Loop through dates array and then echo the list
 foreach ($file_dates as $file_dates){
 $date = $file_dates;
 $j = $file_names_Array[$i];
 $file = $file_names[$j];
 $i++;
 
 echo "File name: $file - Date Added: $date. <br/>""; 
 }
}
?>
I hope this is useful to somebody.

Line 37 of the code above has an error.
echo "File name: $file - Date Added: $date. <br/>""; 
There is an extra " after the <br/> that needs to be deleted in order for this code to work.

Filemtime seems to return the date of the EARLIEST modified file inside a folder, so this is a recursive function to return the date of the LAST (most recently) modified file inside a folder.
<?php
// Only take into account those files whose extensions you want to show.
$allowedExtensions = array(
 'zip',
 'rar',
 'pdf',
 'txt'
);
function filemtime_r($path)
{
 global $allowedExtensions;
 
 if (!file_exists($path))
 return 0;
 
 $extension = end(explode(".", $path)); 
 if (is_file($path) && in_array($extension, $allowedExtensions))
 return filemtime($path);
 $ret = 0;
 
 foreach (glob($path."/*") as $fn)
 {
 if (filemtime_r($fn) > $ret)
 $ret = filemtime_r($fn); 
 // This will return a timestamp, you will have to use date().
 }
 return $ret; 
}
?>

You should avoid feeding the function files without a path. This applies for filemtime() and possibly fileatime() as well. If you omit the path the command will fail with the warning "filectime(): stat failed for filename.php".

Under Windows you can use fileatime() instead of filectime().

filectime running on windows reading a file from a samba share, will still show the last modified date.

If you need file creation time on Mac OS X:
<?php
if ($handle = popen('stat -f %B ' . escapeshellarg($filename), 'r')) {
 $btime = trim(fread($handle, 100));
 echo strftime("btime: %Y.%m.%d %H:%M:%S\n", $btime);
 pclose($handle);
}
?>

Note that on Windows systems, filectime will show the file creation time, as there is no such thing as "change time" in Windows.

If you use filectime with a symbolic link, you will get the change time of the file actually linked to. To get informations about the link self, use lstat.