USE:

  reprtreg  [/t | /p]  [/a | path_name <path_name>]

Options:

  [/t | /p]
  /t specify the output of the registry dump goes to a text file 
  called registry.txt in the local directory.

  /p specifies that the output goes to LPT1.

  [/a | path_name <path_name>]
  /a specifies that the entire registry should be dumped to the 
  specified output.  Warning this will make a file nearly 700K.

  path_name <path_name> indicates to dump one or more specified
  branches, beginning at the path name.  The path name must be a 
  full pathname, prepended by the predefined key it's based off
  of.

  i.e. to dump hardware information, and some general user information   
from the registry to the registry.txt file, type the following on the   
command line:

  reprtreg   /t   HKEY_LOCAL_MACHINE\HARDWARE    HKEY_USERS\THE_USER

  The resulting dump will be prepended with the boot.ini, the config.nt, 
  and the autoexec.nt files.

CAUTION:

  If you type "reprtreg /p /a" on the command line, you better put
  a couple of reams of paper in the printer, and go home til
  morning.  This is nearly 700Kb of information.