Modifying the Library Window Display (Tru64 UNIX)
  At run time, Bookreader searches for one of the following files
  in /usr/lib/dxbook :
      library.decw_bookshelf
      library.decw$bookshelf
      library.bks
  If Bookreader locates one of these files, it displays the books
  and bookshelves listed in the file.  Users can make Bookreader
  look for a file of the same name in a different location by
  defining the environment variable DECW_BOOK as follows:
  %  setenv  DECW_BOOK  /usr/lib/books
  Users can define DECW_BOOK to be a search list by sep-
  arating each location with a space and enclosing the entire
  string in quotation marks:
  %  setenv  DECW_BOOK  "/usr/lib/books  /usr/lib/info"
  When DECW_BOOK is defined as a search list, Bookreader
  displays as bookshelves all the library files it finds in the spec-
  ified directories in the order in which they are listed in the
  definition.  Bookreader opens and displays the contents of the
  first bookshelf it encounters.
  For example, assume DECW_BOOK points to the following
  two directories: /usr/lib/books  and  /usr/lib/info .  When you
  start Bookreader, the following things occur:
  1.   First Bookreader looks in the directory  /usr/lib/books
      for a library files named  library.decw_bookshelf  ,
      library.decw$bookshelf  , and library.bks .  If Bookreader
      finds a file, it displays the contents in the Library window.
  2.   Then Bookreader looks in the directory   /usr/lib/info  for
      a library file.  If Bookreader finds a file, it displays the
      contents in the Library window after the contents of the
      first library file it found.
  To see how DECW_BOOK is currently defined on your
  system, enter the following command:
  %  echo  $DECW_BOOK
  Once you decide to modify the Library window display, you
  can choose one of the following approaches:
  *   Display an alternate library bookshelf instead of
      the default
  *   Add another bookshelf to the default library book-
      shelf
  Both tasks require that you first  create your own book-
  shelf file.
  Additional topics:
  *   Modifying the Library Window Display (OpenVMS)
  *   Bookreader Help Topics