How to fix permissions for files on a server?

Often after you upload files on a server you will get to the point when you won't be able to edit/delete add other files. It happened to me when I unzipped an archive directly on server with a php file.
So how do we change attributes?

set_time_limit ( 0 );
ini_set("memory_limit","1000M");

file_fix_directory(dirname(__FILE__));

function file_fix_directory($dir, $nomask = array('.', '..', 'CVS')) {
  if (is_dir($dir)) {
     // Try to make each directory world writable.
     if (@chmod($dir, 0777)) {
       echo "
Made writable: " . $dir . "
";
     }
  }
  if (is_dir($dir) && $handle = opendir($dir)) {
    while (false !== ($file = readdir($handle))) {
      if (!in_array($file, $nomask) && $file[0] != '.') {
        if (is_dir("$dir/$file")) {
          // Recurse into subdirectories
          file_fix_directory("$dir/$file", $nomask);
        }
        else {
          $filename = "$dir/$file";
            // Try to make each file world writable.
            if (@chmod($filename, 0777)) {
              echo "
Made writable: " . $filename . "
";
            }
        }
      }
    }

    closedir($handle);
  }

}