Command_Qualifiers

/BEFORE
  /BEFORE=time

  Deletes all history information from the history file dated prior
  to the specified date. The deleted information is replaced by a
  single entry stating that history information has been deleted
  from the history file.

  If you omit the /BEFORE qualifier, the default is to remove
  information that was logged prior to the time you enter the
  command. If you include the /BEFORE qualifier and do not specify a
  time, the default is TODAY.

  You can specify the time as an absolute, delta, or combination
  time value, or as one of the following keywords: TODAY, TOMORROW,
  or YESTERDAY. Digital Test Manager interprets TOMORROW as the time at
  which you enter the DELETE HISTORY command.

/CONFIRM
  /CONFIRM (D)
  /NOCONFIRM

  Controls whether Digital Test Manager prompts you to confirm each
  deletion. Valid responses are Yes, No, All, or Quit.

/LOG
  /LOG (D)
  /NOLOG

  Controls whether Digital Test Manager displays informational and
  success messages on your screen.

/OUTPUT
  /OUTPUT[=file-specification]

  Sends output from the DELETE HISTORY command to the specified
  file.

  The output is written to a file called HISTORY.OUT in your
  current directory if you do not specify the /OUTPUT qualifier.
  If you specify the file name without the file type, the file type
  defaults to .LIS.