#
#example: 
#@dir_names = get_sub_dirs($path);
get_sub_dirs
{
   my $dir = shift;
   opendir (D, $dir) || die "can't open directory $dir";
   my @sub_dirs =  grep{/^\d+\s[A-Z]/}
                   grep {!/^\./ && -d "$dir/$_"}readdir D;
   return (@sub_dirs);
}