You don't want the and $_ ne ".\n" in the condition statment. Take that out and put something like: if ($_ eq ".\n") {last;} just before the push line.

#!/usr/bin/perl  -w

use strict;
use diagnostics;

my (@lines);

while (<>) {
  if ($_ eq ".\n") { last;}
  push @lines,$_;
}

foreach (reverse @lines) { print; }
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