As expected... hmm. Define a sample.txt like

1
2
3
[download]

And then run $ test.pl sample.txt

where test.pl is

#!/usr/bin/perl

use strict;
use warnings;

my $i = 0;
while (<>) {
    print $_;
    last if ++$i >= 2;
}

my $line;
print "My extra line: $line" while $line = <>;
[download]

Why would this program then NOT wait for any further input via STDIN ?