Object Mentor Blog: VIM as a Diff/Merge Tool

VIM as a Diff/Merge Tool

Tim Ottinger — Wed, 30 Apr 2008 21:24:00 -0500

Do you need a really quick, clean, powerful diff/merge tool that you can use in windows, mac, and various Unixen? As a happy and pround vim user, I have been enjoying vimdiff for a number of years.

        > gvim -d file1 file2
        > vimdiff file1 file2

(G)vimdiff is wonderful. You can move changes between two versions of a file with great ease (if you know vim) and amazing speed. It can handle files of any size and does a fine job of syncing up both versions.

Vim can do just about anything. I have learned that no matter how much I use and study Vim I still am just scratching the surface of what the editor can do. I find little tricks and configuration options, new keystrokes, and fun little bits of minutae. I think it’s all new. With my memory, sometimes I just think something is new, and have to go check my past notes to see if I already knew it.

Today I (re)learned about diffopt, which makes gvimdiff more wonderful.

    :set diffopt=filler

By default, diffopt is set to “filler”. Filler doesn’t do much, it just adds vertical spaces to keep the text of the left and right pane aligned. It’s a good setting, and I don’t much like working without it. But there are other settings which are overlooked, even by experts.

    : set diffopt+=iwhite

My second favorite is ‘iwhite’, which stands for “ignore whitespace”. It makes gvimdiff ignore leading, trailing, and embedded spaces so that simple acts like retabbing or deleting vertical spaces won’t obscure actual changes. It really helps you to merge changes in situations where you’ve adopted code that was built to entirely different standards.

    :set diffopt+=icase

iCase ignores capitalization, which is not as useful as the other options, since programmers are normally interested in case, but it may be handy when someone has corrected and reformatted SQL. I don’t expect to use it much.

    :set diffopt+=horizontal

The last interesting bit is the choice between vertical splits (the normal case) and horizontal splits (for very long lines on cinema-aspect screens). I hope to never need this option again, but I have needed to deal with absurdly long lines.

If you can use VIM at all, you will find vim’s diffmode to be a very powerful and useful tool. If you can’t use vim already, then maybe vimdiff will be the reason you will learn vim.

"VIM as a Diff/Merge Tool" by tim

Mon, 05 May 2008 00:32:12 -0500

Huh? No graphical indication? You must not have been in diff mode, or you didn’t have syntax enabled. The differences are pretty stark if you have color syntax highlighting turned on, and you have shortcut keys to move between differences.

When I use vimdiff, it collapses the areas where there are no differences. I see a few lines of context, and clearly colored areas of difference (including space changes within a line), and am able to copy changes between the panes pretty easily.

Maybe there needs to be some tutorial here. With screenshots.

"VIM as a Diff/Merge Tool" by Lorne

Sun, 04 May 2008 10:49:18 -0500

You can select two files, right click, and select ‘Diff with Vim’. Easy enough???

"VIM as a Diff/Merge Tool" by pb

Sun, 04 May 2008 09:31:27 -0500

Just what I want – to type in a stupid command line instead of selecting two file and right clicking to choose diff.

"VIM as a Diff/Merge Tool" by AqD

Sun, 04 May 2008 01:56:11 -0500

I found it hard to use for large files without the graphical indication of where the differences are…. There are a lot of GUI diffs that are better for the job and I’d use vimdiff only when I’m on console mode.

"VIM as a Diff/Merge Tool" by Tim

Sat, 03 May 2008 17:56:08 -0500

If you are on *nix, don’t overlook meld. It’s quite a nice tool also. I just tend to do more work with VIM than not.

"VIM as a Diff/Merge Tool" by Rob van Eijk

Fri, 02 May 2008 15:31:11 -0500

I discovered merging through gVim. It works like a charm. I use it to keep my dokuwiki main.php up to date when doing updates.

"VIM as a Diff/Merge Tool" by David Paxson

Thu, 01 May 2008 13:36:41 -0500

I used VIM’s diff feature to compare/merge a base file along with two branches from it. I also had a three monitor setup with the diff spread across the three monitors.

"VIM as a Diff/Merge Tool" by kretik

Thu, 01 May 2008 12:08:55 -0500

Unless you’re doing this because you’re running on *nix, there’s no reason not to use WinMerge. It’s light years ahead of vim’s diff functionality.

"VIM as a Diff/Merge Tool" by Chris Gaal

Thu, 01 May 2008 11:12:42 -0500

I’m an avid Vim user as well, and vimdiff has become an indispensable part of my daily tool kit.

I’d offer two other tips on the topic of using Vim as a diff tool:

- Check out the DirDiff plugin (google “vim dirdiff”). It’s very nice for viewing diffs of directory contents.

- I’ve found it helpful to map Vim’s commonly used diff commands to single keys, and adding in a “zz” command to center the window on the current difference when jumping to the next diff. This allows to you fly though diffs, quickly obtaining/putting changes. I use the following, which uses similar key bindings to Araxis Merge (a tool I used in my pre-Vim life):

nmap <F7> [czz

nmap <F8> ]czz

nmap <F2> do

nmap <F3> dp

"VIM as a Diff/Merge Tool" by A Purohit

Thu, 01 May 2008 11:06:55 -0500

I use vim and its diff tool very heavily. I have defined the following shortcuts

nnoremap <Leader>u :diffupdate<cr>

nnoremap <Leader>g :diffget<cr>

nnoremap <Leader>p :diffput<cr>

(my leader is the comma character)

so I can type ,g to get ,p to put diffs (both commands work with respect to the current window) and ,u to refresh the screen. It really speeds things up.

"VIM as a Diff/Merge Tool" by nicholas a. evans

Thu, 01 May 2008 10:06:47 -0500

I’m an avid vim user, and I often use vimdiff when merging simple changes. But when I’m dealing with conflict resolution, I usually resort to kdiff3, which is available under Linux, Windows, and Mac OS X.

Although I think that meld looks nicer than kdiff3, the UI and workflow of kdiff3 seem the most intuitive to me when dealing with three-way diffs for conflict resolution. And vimdiff is faster and closer to hand than meld when dealing with smaller diff tasks.

"VIM as a Diff/Merge Tool" by Pádraig Brady

Thu, 01 May 2008 09:19:11 -0500

I’ve not liked vimdiff when I tried it. I’ll try again I promise. My current merge tool of choice is meld, which I’ve described here: http://www.pixelbeat.org/programming/diffs/

The important thing to note anyway is that using these tools, is infinitely better than merging manually.