my $exp;

foreach (@hosts) {
        $exp = Expect->spawn("ssh -l $username $_")
                or die "Cannot spawn ssh: $!\n";

        do_exp ($timeout, 'password $', $oldpass);
        do_exp ($timeout, "$username\]", 'passwd');
        do_exp ($timeout, 'password:', $oldpass);
        do_exp ($timeout, 'password:', $newpass);
        do_exp ($timeout, 'password:', $newpass);
}

sub do_exp {
        my ($_timeout, $_lookfor, $_send) = @_;
        if ($exp->expect($_timeout, $_lookfor)) {
                $exp->send($_send);
        } else {
                die "Timeout waiting for $_lookfor.\n";
        }
}