use 5.014;
use Data::Dump 'pp';
use List::Compare;
use Perl6::Slurp;

my @a  = qw(server1 server2 server3 server5);
my @b  = slurp \*DATA, {chomp=>1};
my $lc = List::Compare->new(\@a, \@b);

pp $lc->get_complement; #=> ("server7", "server8")

__END__
server2
server5
server7
server8