SET BACKUP CONTROL STRING    (ULTRIX only)

  Specifies information about backup files for writing out a buffer, saving
  a section file, or creating or updating a command file. You specify if the
  backup filespec contains a location (directory) file name, and version
  number (if any).

  Example:

     The following command creates backup files in the same directory as the
     overwritten file, with the same name as the overwritten file, and
     appends a tilde (~) without a version number:

        Command: SET BACKUP CONTROL STRING !AS!AS~

     Thus, if you write out a file named JABBER.TXT, the backup version is
     named JABBER.TXT~, emulating EMACS file backup.

  Usage notes:

  o  By default, EVE creates backup files. See help on SET FILE BACKUP.

  o  The control string is an FAO control string which allows up to three
     FAO directives that take a parameter. The first directive takes a
     string for the backup file directory, the second takes a string for the
     combined file name and type, and the third takes an integer for the
     version number. For more information about FAO directives, see help on
     TPU FAO.

  o  The default control string is "!AS!AS.!SL" which specifies

        *  Same directory as the overwritten file (the first !AS)
        *  Same name and type as the overwritten file (the second !AS)
        *  Appends a period (".") and a version number (!SL)

     For information about FAO directives, see help on TPU FAO.

  o  To exclude the directory or version number, replace the corresponding
     FAO directive with "!+". However, do not use "!+" for the second FAO
     directive (file name) if you want unique backup file names.

  o  EVE provides parameters for only the first three directives. If you
     specify only two directives, EVE ignores excess parameters when
     creating the backup filespec.

  o  EVE starts backup version numbers at 1. If you write a buffer to a
     different file, or save a different section file, EVE reverts to
     version number 1. If your control string includes a version number, and
     the backup file exists, then EVE increments the version number, and
     tries again, thus, maximizing the version number.

  o  Maximizing the version number does not prevent the backup file from
     having a version number that is lower than that of existing files.
     Deleting files should, therefore, be performed with care.

  o  If you do not specify a version number in your control string, a second
     backup operation will overwrite the backup copy of the original file.
     This prevents recovery from a keystroke journal file because keystroke
     recovery requires the original file (see help on Journal Files). There
     is no effect on buffer-change journaling and recovery.

  o  SET FILE BACKUP is a global attribute, applying to all buffers. To save
     your setting for future editing sessions, use SAVE ATTRIBUTES to create
     a section file or to create or update a command file---see help on
     Attributes.

  Examples:

     Control String    Effect
     ----------------------------------------------------------------------
     !AS!AS.bak        Creates single backup file in same directory as the
                       overwritten file, with the same name and type as the
                       overwritten file, and with ".bak" appended without a
                       version number.

     !+!AS.bak         Same as !AS!AS.bak (above), but creates a single
                       backup file in your working direectory.

     !+!AS!SL          Same as !+!AS.bak (above), but creates multiple
                       versions, each with a version number.

     !+~/back/!AS!SL   Same as !+!AS!SL, but creates the backup files in
                       directory ~/back/.

     !AS!AS~           EMACS-style single backup with tilde (~) appended

     !AS!AS~!SL        EMACS-style with tilde (~) and version numbers
                       appended

     +----------------------------------------------------+
     | SET BACKUP CONTROL STRING applies only on ULTRIX   |
     | systems.  See help on ULTRIX Differences           |
     +----------------------------------------------------+

  Related topics:

     Attributes          SET FILE BACKUP     SET NOFILE BACKUP
     SHOW FILE BACKUP    TPU FAO