How to fix the problem of "Cannot open display"?

[Peng Yu]

On Sun, Oct 4, 2009 at 12:55 PM, Brandon Allbery <allbery at kf8nh.com> wrote:
> On Oct 4, 2009, at 13:53 , Peng Yu wrote:
>>
>> $ gnome-terminal
>> $Failed to parse arguments: Cannot open display:
>
>
> Unless you built Gtk+ with native Aqua support (which I think won't yet work
> with GNOME stuff), you need to install and run Apple's X11.

My OS is leopard. Would you please point me where I should download
it? And how to install it? Thank you!

Regards,
Peng