use Modern::Perl;

my $lastrow = "";

open my $fh, '<', 'fail.txt' or die $!;

while (my $line = <$fh>)
{
    next unless $line =~ /\S/;
    
    if ($line ne $lastrow)
    {
        print $line;
        $lastrow = $line;
    }
}

close $fh;

##</code><code>##

hostname1.com
Gateway FAIL
hostname2.com
Gateway FAIL
Gateway FAIL