<?php
  echo '<pre>'; 

  $file_name = "FULL_PATH_TO_ANY_FILE";
  $st = stat($file_name);
  $group = posix_getgrgid($st['gid']);
  $user = posix_getpwuid($st['uid']);
  $user_name = $group['name'];
  $group_name = $user['name'];

  print_r($st);

  echo "User Name: $user_name\n";
  echo "Group Name: $group_name\n";

  echo '</pre>';
?>