Can I see changes before I save my file in Vim?

Question

I use Vim. I open a file. I edit it and I want to see what I\'ve edited before I save it.

How can I do this in Vim?

Answer 1

Source the following and use :DIFF command

function! s:diff()
    let tmpa = tempname()
    let tmpb = tempname()
    earlier 100h
    exec 'w '.tmpa
    later 100h
    exec 'w '.tmpb
    update
    exec 'tabnew '.tmpa
    diffthis
    vert split
    exec 'edit '.tmpb
    diffthis
endfunction
command! -nargs=0 DIFF call diff()