Re: backup-each-save.el

[Francesco Potorti`]

>I know emacs makes backup files (~-files) but that appears to take
>place among file visits (series of opens and closes), not among file
>saves.

It does, if you give a prefix to C-x C-s:

C-x C-s runs the command save-buffer
   which is an interactive compiled Lisp function in `files'.
(save-buffer &optional ARGS)

Save current buffer in visited file if modified.  Versions described below.
By default, makes the previous version into a backup file
 if previously requested or if this is the first save.
With 1 C-u, marks this version
 to become a backup when the next save is done.
With 2 C-u's,
 unconditionally makes the previous version into a backup file.
With 3 C-u's, marks this version
 to become a backup when the next save is done,
 and unconditionally makes the previous version into a backup file.

With argument of 0, never make the previous version into a backup file.