Thank you very much for your collaboration. I will follow your advice. Even though the time is a determining factor, I will try to learn Perl to understand the code of your programs in detail. If in the next days you decide to give me the emails of the other people, I will be highly thanked with you. Again I appreciate all your collaboration. You do not forget that you can contact to me whenever you want. Any thing that you need, please you do not doubt in writing to me. my email is rocasoc@hotmail.com