use Text::CSV_XS "csv";

my $hr   = csv (
    in           => "hr.txt",
    key          => "samaccountname",
    keep_headers => \my @keys,
    );

my $aoh = csv (in => "ad.txt", bom => 1, on_in => sub {
    my $sam = $_[1]{samaccountname} or die "No name in AD";
    my $ahr = $hr->{$sam};
    unless ($ahr) {
        warn "I got AD data for $sam, not in HR\n";
        next;
        }
    my @diff = map { [ $_, $ahr->{$_}, $_[1]{$_} ] }
        grep { $ahr->{$_} ne $_[1]{$_} } @keys;
    @diff or return;
    say "Changes for samaccount $sam";
    printf "  %-22s %-27.27s -> %s\n", @$_ for @diff;
    });