/sys$common/syshlp/helplib.hlb EDIT, /TPU, /WRITE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  /WRITE    (default)
  /NOWRITE

  Determines whether exiting writes the main (or first) buffer to a
  file.  If you specify multiple input files on the EDIT/TPU command
  line, this qualifier applies to each buffer.  Does not affect other
  buffers you create during the editing session.

  /WRITE is the same as /NOREAD_ONLY---on exiting, EVE writes out the
  MAIN (or first) buffer to a file if the buffer has been modified, and
  if necessary, EVE prompts you for the output file name.

  /NOWRITE is the same as /READ_ONLY.  For EVE, this makes the MAIN (or
  first) buffer write-locked and also makes it unmodifiable, unless you
  used /MODIFY.  Use /NOWRITE to view a file without making any
  changes.  For example, the following command lets you view a file
  named STAFFMEMO.TXT, so you can use cursor-movement commands but
  cannot change the text:

     $ EDIT/TPU staffmemo.txt /NOWRITE

  In EVE, the status line shows whether the buffer is read-only or
  write.  Also, you can change the read/write and modification
  attributes of the buffer during your editing session by using the SET
  BUFFER command.