Start X

To Start an X server use the command:

      startx.

startx initializes an X session it is a front end to xinit,
that provides a nicer user interface.

Display

Start an application on some X server (e.g., an xterm): xterm -display host:0.0
host (e.g., localhost): machine on which the X server is running.

       0.0 : Display and Screen.

X supports multiple physical screens in its specification.

To specify the default display for a session
use the DISPLAY environment variable: DISPLAY=localhost:0.0 export DISPLAY

Access Rights

Fortunately not anyone on the Internet can
start an application on your display.
By default, X prohibits access from all machines
except your own. The xhost command enables access:

Example (enable access to anyone):

       xhost +

A secure X connection with ssh

You may connect to an X-sever and transmit data via ssh (secure shell):

 ssh -X user@remote_host

Any X application that you open on remote_host will be displayed on the machine where you opened the ssh.