...
opendir(DIR, $all_session) or die "Couldn't open directory, $!";
  while (my $sessions = readdir DIR) {
      # Use a regular expression to ignore files beginning with a period
      next if ($sessions =~ m/^\./);
      next if ($sessions !~ /^cgisess_[a-f0-9]{32}$/);
      if( -M qq{$all_session/$sessions} > 360){ # 6 minutes
          print "Del these session files: $sessions<br>";}

    }
closedir DIR;
...