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Wireshark-users: Re: [Wireshark-users] (wireshark:26800): Gtk-WARNING **: cannot open display:

From: Greg Toombs <greg.toombs@xxxxxxxxxxxxxx>
Date: Wed, 12 Dec 2007 01:41:40 -0500
Stephen Fisher wrote:
> Wireshark doesn't install any window manager specific things at this time other than providing a wireshark.desktop file.
>   
Right, but the desktop file should have two entries, not one. (Or two
desktop files? I don't know how it works.) This is done by default in
Ubuntu, for one.
> sudo/su doesn't always carry your environment variables to the program being run as root.  To verify this is happening, try sudo echo $DISPLAY and verify it is blank.
echo $display
:0.0

sudo echo $display:
:0.0

sudo su
echo $display
<blank>
> If so, try adding the DISPLAY variable assignment to your root shell's startup dot-file and see if that works.
When I su and then set the variable, the output changes to:

Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified

(wireshark:26949): Gtk-WARNING **: cannot open display: :0.0

>  Your sudo may also have an option to preserve environment variables such as DISPLAY when running. I don't have a Linux machine handy at the moment to try it out, but on MacOS X sudo does preserve environment variables and has an option not to.
I think it would be more proper to set the default environmental
variables for the root user, instead of temporarily transferring those
from the non-root to root user during sudo. Either way, it looks like it
isn't just a $display problem.

-- 

Greg Toombs