If you encounter the problem of being unable to start an X application through an
ssh-tunnel and run into an error message similar to
Can't open display
RuntimeError: could not open display
you should check
- that you used
ssh -X[...]to enable X11 forwarding when connecting to the server
- that the
xauth-package is installed correctly on your server
xauth is used to edit and display the authorization information used in connecting to an X server.
For example, after installing a minimalistic CentOS the
xorg-x11-xauth package is not necessarily installed as well.
The solution is quite simple:
yum install xorg-x11-xauth
does the trick! You may have to reconnect to give
xauth the opportunity to create a new authority file for you user (