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This question already has an answer here:

I'm not able to start any GUI applications as a root user:

# pgrep -lf Xorg
1590 /usr/bin/Xorg -br -nolisten tcp :0 vt7 -auth /var/lib/xdm/authdir/authfiles/A:0-PNnJzp
# echo $DISPLAY
# xeyes
No protocol specified
Error: Can't open display: :0
# firefox
No protocol specified
No protocol specified
Error: cannot open display: :0
# xcalc
No protocol specified
Error: Can't open display: :0

Distribution is openSUSE 11.2( 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?

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migrated from serverfault.com Mar 6 '13 at 21:27

This question came from our site for system and network administrators.

marked as duplicate by Gilles, warl0ck, n0pe, jasonwryan, Mat Mar 7 '13 at 5:39

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

This isn't really an SF question, and will probably get transferred soon, but you might want to look into the xauth command and see what you can learn about how the X server makes decisions about who should be allowed to perform operations through it. – MadHatter Mar 6 '13 at 8:38

: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: http://serverfault.com/questions/51005/how-to-use-xauth-to-run-graphical-application-via-other-user-on-linux

To add the xauth key from your user logged into X to the root user.

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