Thank you very much for correcting me... As I explain in my comments, I'm not really a programmer, and, well, I'm begining with perl. You are right! I have downloaded the script and found a difference with the one I use... I don't declare "my $size=1024". If you do this, the script will work. I think I posted the code before correcting the bug :-( With $no_partes, what the script do is read parts of $MAX_SIZE_PART. When $no_partes is less than $MAX_SIZE_PART it gets out with the rest of the file. Ej: 120 mgs into 50, 50 and 20. Thank you for your advice about @ARGV... I'm not very clear about the use of the arguments by now. I have to learn a lot yet ;-) And it's true, I should better read and write a chunk at a time... In fact, my hard disk seems like if it's going to explode each time I run the script. I know that the first thing to do when you want to program in Perl is look at the CPAN, but I know that the best way for learn programing is make programs... And I was sooo proud about this script! Well, I'll try to be more careful with the code before post it. Thank you.