vim Backup

Wie mache ich autom. ein Backup der Datei die gerade bearbeitet wird?

~/.vimrc

set mouse=r
syntax on
colorscheme torte

" check with F8 the changes from the modified and original file
nmap <F8> :w !diff % - 2> /dev/null<CR>

" create variable for .vimconf
let vimconf = expand('%:p:h') . "/" . ".vimconf"

" if .vimconf file exists in the directroy load it
if filereadable(vimconf)
        exec "source".fnameescape(vimconf)
endif

Jetzt muss nur noch das file .vimconf in das Verzeichnis kopiert werden, wo vim autom. Backup's erstellen soll

.vimconf

" create variable of the archive directory
let archivedir = expand('%:p:h') . "/" . "archive"

" disable restore screen after vim exit, it's required for diff output
set t_ti=""
set t_te=""

" check if archive directory is available, created if needed
if !isdirectory(archivedir)
    call mkdir(archivedir , "p")
endif

" enable backup and set backup directory
set backup
set writebackup
let &backupdir=archivedir

" run autocommand and save "original" file before the modified file will be saved
autocmd BufWritePre * let &backupext = '_' . strftime("%Y%m%d_%H%M%S")
autocmd BufWritePre * :silent !cp -f % $(echo %:p:h)/archive/$(echo %:t)_old 2> /dev/null

" make a diff of the file new file and old file
autocmd VimLeave * :silent !echo -e "\n\n******************************\n*** diff new_file old_file ***\n******************************\n\n------ diff begin ------" ; diff % $(echo %:p:h)/archive/$(echo %:t)_old 2> /dev/null | less -FeX ; echo -e "------ diff end --------" ;rm -f $(echo %:p:h)/archive/$(echo %:t)_old 2> /dev/null