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

If you want to use vim for comparison like in vimdiff, you could do something like this:

Edit your .vimrc and add:

nmap  :w !vim -M -R - -c ":vnew % \| windo diffthis"

From there on you will see your changes and can quit the diff view using qall like in vimdiff by pressing F8 in command mode. Replace F8 with any key you like.

Edit: Added -M to disallow any modification, because it is not save.