Requests the internal command interpreter to read subsequent command
  input from a specific file or device.  The file can contain any valid
  interactive command.  Command files can be nested to 16 levels.  The
  file type defaults to .COM.

  Format:  @file-spec

  If the logical name SHOW_CLUSTER$INIT is defined, SHOW CLUSTER uses the
  directory defined by SHOW_CLUSTER$INIT to locate the command file specified.
  If SHOW_CLUSTER$INIT is not defined, SHOW CLUSTER looks for the command file
  in the current default directory.

  To execute a command procedure upon invoking SHOW CLUSTER, define the
  logical name SHOW_CLUSTER$INIT to equate to the filespec you want
  SHOW CLUSTER to execute.  The file type defaults to .INI.