Initializes the SYSGEN work area with the system parameter values from
  a parameter file, the system image, the active system, or the default
  list.


  Format:

    USE file-spec
    USE CURRENT
    USE ACTIVE
    USE DEFAULT

Additional information available:

CURRENTACTIVEDEFAULT

file-spec

  File specification of a previously created system parameter file;
  file type defaults to PAR.

  Obtains the system parameter values from the current system image.

  Obtains the system parameter values from the active, running system.

  Obtains the system parameter values from the default list.