#!/usr/bin/perl

use strict;
use warnings;

die "Usage: $0 <file> [<files>]\n" unless @ARGV;

open my $fh, '<', shift or die $!;

while (<$fh>) {
    # ...
}

while (<>) {
    # ...
}

__END__

##</code><code>##

while (<>) {
    # ...
    last if eof(ARGV);
}

while (<>) {
    # ...
}