sub process_file {
  my $file=shift;
  
  open(IN,"<$file") || die "Couldn't open '$file': $!\n";
  my @in=(<IN>)[0..9];
  close IN;

  if (join('',@in)=~/\r\n/m) {
       ## found!
       ## do something exciting here
  }
}

##</code><code>##

  push @in,scalar <IN> for 1..10;