Using environment variables

When you start a Graphical Environment session, the $DISPLAY, $HOME, and $PATH. environment variables are set. When you run the Desktop client, the $LANG environment variable is also set.

The $PATH and $HOME environment variables are actually set when you first log in, whether through a multiscreen running getty or through scologin. However, the X server modifies the $PATH variable to include the /usr/bin/X11 directory.

The $DISPLAY and $LANG environment variables are described below:

• The $DISPLAY environment variable is used to tell a client to which server it should send its output.

  The X display consists of one or more screens, a keyboard, and a mouse. A system may have several displays, and each display may, in turn, have more than one screen. Each display has exactly one server process controlling all its input and output. Therefore, the terms ``display'' and ``server'' are used synonymously.

  When a client is run, it must open a connection to a display. You must be able to tell the client the name of the display that you want it to use for output. You can also indicate a specific screen for the display. Because the display can be anywhere on the network, you have to provide the network name of the system to which the display is connected to fully identify the display.

  Use the following format when setting the $DISPLAY variable:
  
  [hostname]:display_number[.screen_number]

  where:

  
  hostname

  specifies the name of the machine to which the display is connected, and must be either a machine name or the machine's network address. If the hostname is not specified, the client assumes it should communicate with the display on the same machine.

  
  :display_number

  specifies the number of the display, or X server, that you want the client to use. Each display on a system is assigned a :display_number. If the display is managed by scologin, the :display_number is specified explicitly in the /usr/lib/X11/scologin/Xservers file. If the X server is started by startx, the server is assigned the first available :display_number, starting with ``:0''.

  Usually, if only one X server is running, its :display_number is ``:0''. If more than one server is running on your system, you must determine which display number corresponds to the X server you want to specify.

  
  screen_number

  specifies the screen on which the server is running.

  The default display name is stored in the $DISPLAY environment variable when the X server is started by either scologin or the startx script. However, if you want a client to use a different display, you must reset the $DISPLAY variable so it specifies the other server.

  For example, to run your clients on a remote server on a machine named scooter, you would enter:

  DISPLAY=scooter:0.0; export DISPLAY	(for sh, ksh)
  or
  setenv DISPLAY scooter:0.0	(for csh)

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  NOTE: Most clients understand the -display command line option. This option temporarily overrides the contents of the $DISPLAY variable. For more information on using this command line option, see ``Understanding resources''.

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• The $LANG environment variable specifies the language that is used on your system. By default, the $LANG variable is set to ``english_us.ascii''.