use Expect;
$Expect::Debug = 1;
my $string= '/usr/bin/ssh 127.0.0.1';
my $exp=Expect->spawn($string) || die "error $!\n";

$exp->expect(2, "password: ");
$exp->send("XXXXXXXX\n");
$exp->expect(2,'$');
$exp->send("ls\n");
$exp->expect(2,'$');

##</code><code>##

$exp->interact();