REG LOAD KeyName FileName /reg:32 | /reg:64 KeyName ROOTKEY\SubKey (local machine only) ROOTKEY HKLM | HKU SubKey The key ...

REG LOAD KeyName FileName [/reg:32 | /reg:64]

  KeyName    ROOTKEY\SubKey (local machine only)
    ROOTKEY  [ HKLM | HKU ]
    SubKey   The key name to load the hive file into. Creates a new key.

  FileName   The name of the hive file to load.
             You must use REG SAVE to create this file.

  /reg:32  Specifies the key should be accessed using the 32-bit registry view.

  /reg:64  Specifies the key should be accessed using the 64-bit registry view.

Examples:

  REG LOAD HKLM	empHive TempHive.hiv
    Loads the file TempHive.hiv to the Key HKLM	empHive