Screen brightness settings, are there any commands?

[Than Ngo]

you can use xgamma or xrandr to adjust gamma. 

Than

> I have problems with bug 722745
> (https://bugzilla.redhat.com/show_bug.cgi?id=722745), but I have heard
> that there are other ways to control the screen brightness settings.
> Are there any special commands you can do in addition to the gnome
> screen brightness settings? That would probably help regarding that
> bug.
> 
> /Andreas