Why Can't I Install Software As Root?

When I become root with "su -" and try to install some software, such as firefox, it then says:"(firefox-installer-bin:3645): Gtk-WARNING **: cannot open display:" What's the meaning of this information? And how can I deal with it?Thanks!

Thats a harmless warning, it happens all the time to me, but the software will continue run (installer or whatever).

Hi...

this is becouse display :0.0 is used by another user and when you try to run it as root (by su) you violate the security, since it work like you want to run it from another computer... first you must know what display you use (usualy :0.0, but who knows...) as normal user (without su, just like that), do:

echo $DISPLAY

, then you should add your host (again as usual user), do:

xhost +localhost

and you should see something like:

localhost being added to access control list

then switch user (do su ) and export display (take value that gives you echo... do

export DISPLAY=:0.0

if it was :0.0.

that should make the case, hope this helped

PS.: Yes, I think it will continiue to run it it is console aplication, but as I remember firefox also got gtk graphic based installer, and there you must get access to display it...

aslong as you firewall tcp port 6000 (and 6001 + if you are running more than one X server)there is no ecurety risk from disableing this securety feature by deafualt, many distro's like redhat / fedora do.

Why don't you just go to wherever X is running (in most cases it is accessed by pressing Ctrl+Alt+F8, if that doesn't work, try that with F7, F9 and so on) and log in as root there?In GNOME or KDE, you can log out as your normal user and log in as root. Or you can open up a terminal there and use sudo to access your installation file.

Why don't you just go to wherever X is running (in most cases it is accessed by pressing Ctrl+Alt+F8, if that doesn't work, try that with F7, F9 and so on) and log in as root there?
In GNOME or KDE, you can log out as your normal user and log in as root. Or you can open up a terminal there and use sudo to access your installation file.

Maybe he's logged in as a normal users under X and is he trying to install something by launching it as root via a terminal ?

Oh well in that case, just log out as normal user and log in as root on the X server.

Edited September 17, 2008 by FirefoxRocks (see edit history)

Just simply use sudo to do the action. Sometimes doing su on some distributions limit you purposefully or try right clicking the file on your file manager and type kdesu sh and press OK. It will launch a password window and let you run the application as root. In GNOME, it should be the same but replace kdesu with gnomesu.xboxrulz