sub change_password {
    my ($host, $ssh) = @_;
    my ($pty) = $ssh->open2pty('passwd');
    my $expect = Expect->init($pty);
    $expect->raw_pty(1);
    # $expect->log_user(1);
    if (answer_passwd($expect, 'current.*:', $old)    and
        answer_passwd($expect, 'Enter new.*:', $new)  and
        answer_passwd($expect, 'Retype new.*:', $new) and
        $expect->expect($timeout, "success")) {
        exit(0);
    }
    exit(1);
}