It seems someone taught you how to program outside of Perl before she taught you how to program inside of Perl. ;-)

Here's my riff on kcott's script…

#!/usr/bin/env perl

use strict;
use warnings;

use autodie qw( open close );
use English qw( -no_match_vars );

my $input_file  = 'input.txt';
my $output_file = 'output.txt';

my $start = 17;
my $end   = 30;

open my $input_fh,  '<', $input_file;
open my $output_fh, '>', $output_file;

LINE:
while (my $line = <$input_fh>) {
    next LINE if $INPUT_LINE_NUMBER < $start;
    last LINE if $INPUT_LINE_NUMBER > $end;

    print {$output_fh} $line;
}

close $input_fh;
close $output_fh;

exit 0;
[download]

And here's a greatly reduced version using <ARGV> and STDOUT instead of hardwiring file names inside the script…

#!/usr/bin/env perl

use warnings;

while (<>) {
    next if $. < 17;
    last if $. > 30;

    print;
}
[download]