backup.vim

set backup
set backupdir=~/.vim.d/.bak

augroup backup
    autocmd!
    autocmd BufWritePre,FileWritePre,FileAppendPre * call UpdateBackupFile()
    function! UpdateBackupFile()
        let basedir = expand("~/.vim.d/.bak")
        let dir = strftime(basedir."/%Y%m/%d", localtime()).substitute(expand("%:p:h"), '^C:', '' , '')
        if !isdirectory(dir)
            call mkdir(dir, "p")
        endif

        exe "set backupdir=".dir
        let time = strftime("%H-%M", localtime())

        exe "set backupext=.".time
    endfunction
augroup END