I'm not able to start any GUI applications as a root user:# pgrep -lf Xorg1590 /usr/bin/Xorg -br -nolisten tcp :0 vt7 -auth /var/lib/xdm/authdir/authfiles/A:0-PNnJzp# echo $DISPLAY:0# xeyesNo protocol specifiedError: Can't open display: :0# firefoxNo protocol specifiedNo protocol specifiedError: cannot open display: :0# xcalcNo protocol specifiedError: Can't open display: :0#Distribution is openSUSE 11.2(2.6.31.5-0.1-default) and X.Org X Server version is 1.6.5. My DISPLAY variable is set correctly, isn't it? Any ideas what might cause this problem?
X Can't open display: :0 while DISPLAY variable is correct
xorg;display
:0 should work as should :0.0 (normal default) as also localhost:0 etc. Permissions are most likely problem.Try disabling xhost with: xhost +(This is unlikely to work but easier to do than the following which is required if it didn't).So if that fails it's probably xauth.Follow the first answer on here: https://serverfault.com/questions/51005/how-to-use-xauth-to-run-graphical-application-via-other-user-on-linuxTo add the xauth key from your user logged into X to the root user.