If I understood correctly you are looking for a way of reading a file in chunks of 10 lines. Probably you can use cpan modules for that (Tie::File or DB_File). But this is another way (using an iterator):

use strict;
use warnings;

sub getNlines
  {
    my ($fh,$nLines) = @_;
    return sub {
      my $linesRead = 0;
      my $rec;
      $rec .= <$fh> for (1..$nLines);
      return $rec;
    }
  }

open my $ff, "<", shift @ARGV or die $!;
my $get10lines = getNlines($ff,10);  ## will retrieve 10 lines per cal
+l
while (my $rec = $get10lines->()){
  ## Process next 10 lines
  print "$rec\n";
}
[download]

Hope that this helps

citromatik