open my $fh, "<", $filename
    or die "Can't open $filename: $!\n";

my $lastline;
$lastline = $_ while <FILE>;
print "$lastline\n";
[download]

Or

use Tie::File;
tie my @file, 'Tie::File', $filename
    or die "Can't open $filename: $!\n";
print @file[ -1 ];
[download]

Or

use File::ReadBackwards;
tie *FH, 'File::ReadBackwards',  $filename
    or die "Can't open $filename: $!\n";
my $lastline = <FH>;
print $lastline;
[download]

Or any of a myriad others.

Which one to pick depends on your precise circumstances.