I know you would normally enter into vimdiff mode from the terminal with vimdiff file1 file2. However, I frequently find myself already in vim with multiple different splits, and I'd like to run vimdiff on two specific splits, and then turn vimdiff off.

How would I go about this?

N.B. there might be other splits in my vim session that I don't want to be comparing. So I might have 4 vertical splits and I want to run vimdiff on split 1 with split 3, look at some differences, and then turn the diff off.

2 Answers 2


The command is called :diffthis. It must be executed in every window you want to add to the comparison.

The inverse is :diffoff which exits diff mode in the current window. To exit diff mode in all applicable windows add a bang: :diffoff!.

  • 2
    The cod mapping from tpope's unimpaired can be handy.
    – mMontu
    Commented Mar 12, 2020 at 13:07
  • @mMontu It maps exactly to diffthis / diffoff. So it's useful if you're already using vim-unimpaired. Otherwise, it's not a problem to create such mapping yourself.
    – Matt
    Commented Mar 12, 2020 at 14:39
  • @Matt glorious - thank you, this works a treat.
    – Aeroblop
    Commented Mar 12, 2020 at 15:22
  • 4
    To quickly accomplish this in your splits, you can use :windo as in ":windo diffthis".
    – jpheldson
    Commented Mar 12, 2020 at 20:28

Noting that two :diffthis commands ought to be issued with the existing two-split view, here's a quick Autohotkey snippet that does the trick - it simply emulates key-input to the Vim window by issuing :diffthis twice.

            send :diffthis
            send {enter}
            send ^w
            send w
            send :diffthis
            send {enter}

Looking forward to a native Vimscript/Lua-based solution.

Correction: :windo diffthis does the trick!

Kudos to Christian Brabandt.

Note, :windo diffoff achieves the same function as :diffoff!.

  • 4
    easier: :windo :diffthis if only two splits are opened Commented Aug 4, 2022 at 6:50

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