oio11

export DISPLAY="127.0.0.1:10.0"

sudo service ssh restart

http://www.x.org/wiki/FAQErrorMessages#AlreadyActive

Could not get lock /var/lib/dpkg/lock

sudo dpkg --set-selections < package.list && sudo apt-get dselect-upgrade

sudo dpkg --configure -a

??? sudo fuser -vki /var/lib/dpkg/lock; sudo dpkg --configure -a

sudo rm /var/lib/dpkg/lock

sudo rm /var/lib/apt/lists/lock

sudo rm /var/cache/apt/archives/lock

http://unix.stackexchange.com/questions/59337/xming-debian-cant-open-display

startx -- :1

rm -rf /tmp/.X0-lock

~/.Xauthority required but missing

ln -s "$XAUTHORITY" ~/.Xauthority

ls -la ~/.Xauthority

??? x11vnc -display :0 -auth /home/USER/.Xauthority

export XAUTHORITY=/home/user/.Xauthority
su
xclock

http://www.linuxquestions.org/questions/linux-software-2/cannot-open-display-as-root-352200/

had same issue after syncing my home folder on Ubuntu 12.04. I resolved it using following commands:

rm ~/.Xaut*

Then i logged out and re-logged in. Following warning arisen:

/usr/bin/xauth:  file /home/iranice/.Xauthority does not exist

After that, Linux created .Xauthority file automatically. I logged out and re-logged in and everything was OK :)

Good luck

http://superuser.com/questions/315050/xauth-x11-ssh-forwarding-problem

http://askubuntu.com/questions/40320/unable-to-copy-the-users-xauthorization-file

http://askubuntu.com/questions/124038/xauthority-required-but-missing

/etc/network/interfaces -- configuration

# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

# The loopback interface
auto lo
iface lo inet loopback

# The first network card - this entry was created during the Debian installation
auto eth0
iface eth0 inet dhcp

partconf-mkfstab

###################################################################################

Making X windows work after su or ksu

If you get the following error message

> xclock
X11 connection rejected because of wrong authentication.
X connection to localhost:10.0 broken (explicit kill or server shutdown).

The problem is that X uses an authentication mechanism called xauth
which runs when you log in. When you use su or ksu to switch your
identity, the xauth file of the new identity has different magic
cookies than your local X server knows about and you get the above
message.

To fix this, you need to take your original magic cookie that xauth
initially sets up and copy it into the xauth file of the new
identity. Under your original identity, do the following:

unity% echo $DISPLAY
localhost:10.0

This tells you the display number that was setup for you via SSH. In
the example the display number is 10.

unity% xauth list unix:10
linux00xen.unity.ncsu.edu/unix:10 MIT-MAGIC-COOKIE-1 79f6967b5f825931b17dfc0002f45748

Note the display number in the above command! This prints out the
cookie for your display. Put that string into your copy buffer. Next
switch to the new identity:

unity% sudo su -
Password:
# xauth add linux00xen.unity.ncsu.edu/unix:10 MIT-MAGIC-COOKIE-1 79f6967b5f825931b17dfc0002f45748
xauth: creating new authority file /root/.Xauthority

You should now have the authentication for X setup. Try running the X app and it should work.

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http://www.lns.cornell.edu/~dlr/acceleratorphysics/computing/unix.txt