my $x=0;
for (my$a=0; $a<10; $a++)
{
   open (file);

   # Read the column headers
   my $line = <file>;
   print $header, "\n";
   my @keys = split /\t/, $line;

   # Process the data
   while ($line = <file>)
   {
      # The stuff inside the original else clause
      *Does some filtering as each line is read in*
   }
}