1.$ WRITE SYS$OUTPUT F$UNIQUE()
      414853555241159711D7DF797CCF573F
      $
      $ WRITE SYS$OUTPUT F$UNIQUE()
      414853555241509811D7DF797E3F2777
      $

      This example shows how a unique string is returned on
      subsequent WRITE commands.

    2.$ OPEN/WRITE TEMP_FILE 'F$UNIQUE()
      $ DIRECTORY

      Directory WORK1:[TEST]

      594B53554C421C9C11D75463D61F58B7.DAT;1

      Total of 1 file.
      $
      $ CLOSE/DISPOSITION=DELETE TEMP_FILE
      $ DIRECTORY
      %DIRECT-W-NOFILES, no files found
      $

      The first command creates a temporary file and gives it a
      unique name, which is displayed by the subsequent DIRECTORY
      command. After the file is later closed and deleted, it no
      longer shows up in the directory.