startx                                         #Start X-Server
startx -- :1                                   #Start 2. X-Server (Desktop)
startx /path/to/program/ -- :1                 #Start programm in 2. X-Server
startx fluxbox -- :1 -config xorg2.conf        #Start 2. X-Server with program "fluxbox" with second screen-resolution

sax2                                           #Repair X-Server (on Suse)

Text x-config tool runs in text mode:

xf86config

xorg.conf manuelly:

xorgconfig                                     #Creates /etc/X11/xorg.conf

Order when X-Server starts:

startx -> xinit -> xinitrc -> xclients

Execute X on Remote PC and show output locally:

ssh 123.123.123.123 Name, Passwort
export DISPLAY=dozentRechner:1                 #":1" = 2. X-Server(Default DISPLAY=“0:0“)
xeyes & Programm                               #Execute on 2. X-Server

DISPLAY=IP:0.0
export DISPLAY
echo $DISPLAY

startkde -display local_machine_name:0.0 &

Show programm on 2. screen:

export set DISPLAY=192.168.0.1:0               #Displays on first monitor of 192.168.0.1 host
export set DISPLAY=192.168.0.1:1               #Displays on second monitor of 192.168.0.1 host
export DISPLAY=:1:0; mozilla
export DISPLAY=localhost:10.0                  #Setup by connceting remote via ssh (putty) and xming (X-Server for Windows)

Start “xrandr” on X-Terminal:

xrandr                                         #Show config and screen resolution

Example: VGA-Montior start (on CRTC 1) with:

xrandr --output VGA-0 --auto --crtc 1 

Laptop-Screen shutdown with:

xrandr --output LVDS --off -> ok

VGA-Montior set on CRTC 0:

xrandr --output VGA-0 --auto --crtc 0 

xdm:

chkconfig xdm                                   #Check if "xdm" is running
/var/log/*X*.log                                #For indication as to why it's failing to load at start.

Install gnome:

sudo apt-get install ubuntu-desktop
sudo apt-get install gdm
sudo /etc/init.d/gdm start
sudo dpkg-reconfigure xserver-xorg
sudo update
sudo upgrade

To run a X11-Programm with root, if direct root-login is not allowed:

• Login with your normal user (don´t execute “sudo su -” during login)
• xauth -f ~/.Xauthority extract /tmp/Xauthtmp :10
• Start an external X-Server (such as Xming)
• sudo su -
• xauth merge /tmp/Xauthtmp
• export DISPLAY=localhost:10.0
• xclock (or another X-Programm)