another idea...
If you don't want the last two lines you could truncate them

open(F, '+<afile.txt') || die 'cannot open afile.txt';
while (<F>) {
    push(@addrs, tell(F)) unless eof(F);
}
truncate(F, $addrs[-2]) || die 'cannot truncate afile.txt';
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This will remove the last two lines in a file.
I got the idea for this in the Perl Cookbook. Recipe 8.10
If you don't have that book I recommend it.