are you using strict and warnings? i can't tell from your code, but i don't see any my declarations. your example of the while/if/last loop should work. that is, last should exit the while loop. here's my code, it works. the output is below it.

#!/usr/local/bin/perl -w
use strict;
$|++;

my $r;
while($r=<DATA>) {
    print "hi$r";
    if($r eq "\n") {
        last;
    }
    print "bye$r\n";
}

__DATA__
1
2
3

4
[download]

the output:

C:\WINDOWS\Desktop>perl test_last.pl
hi1
bye1

hi2
bye2

hi3
bye3

hi

C:\WINDOWS\Desktop>
[download]

are you certain "\n" is the condition you need to stop the loop? or is it EOF? if it's the end of the file you're looking for, i'd suggest something like

#!/usr/local/bin/perl -w
use strict;
$|++;

while(<DATA>) {
    print "$_";
}

__DATA__
1
2
3
4
[download]

if you're not using strict, you might want to read up on it. start here, at Use strict warnings and diagnostics or die.

~Particle