Example to list only files matching totalpages_????_??_CITS.txt
from the current directory.
$dirname = ".";
print $dirname . "\n";
opendir(DIR,$dirname);
@totalpagesfiles = grep{/totalpages_\d{4}_\d{2}_CITS.txt/gi} readdir(DIR);
closedir(DIR);
foreach $tpf (@totalpagesfiles)
{
print "$tpf\n";
}