Comparing two files in Vim

Question

Is it possible to view two files side-by-side in Vim? If so, how can I set up my editor to do this, and is there a way to diff between the two files within Vim?

I am aware of the :next and :prev commands, but this is not what I'm after. It would really be nice to view the two files in tandem.

Solution 1

Open the side by side view:

Ctrl+w v

Change between them:

Ctrl+w h or l

You can then open another file for comparison in one side by entering a command such as:

:e file2.txt

Checkout the vimdiff command, part of the vim package, if you want a diff-like view, e.g.:

vimdiff file1.txt file2.txt

Solution 2

You can also open vim in split-screen mode, with the -O option:-

vim -O file1 [file2 ...]

To then turn on diff mode, you need to run the :diffthis command in each pane.

Another use-case scenario, is if you've already got one file open in vim, and you want to open and compare it against another. Then you can use the following vim commands:-

:vs otherfile (open otherfile in vertical split screen)
:diffthis (turn on diff mode in original file)
Ctrl+w l  (swap to newly opened file)
:diffthis (turn on diff mode in opened file)

You can then turn off diff mode in each pane with the vim command :diffoff.

EDIT
And the other standard one that hasn't been mentioned:-

vim -d file1 [file2 ...]

This is equivalent to calling vimdiff directly.

Solution 3

Or just open the first file in VIM, then :vert diffsplit file2 :vert makes it split the screen vertically.

diffsplit does a diff, and splits the files and scrolls locks them.

Solution 4

While it has already been answered how to start the diff, it's also important how to stop it in all windows. For completeness, I repeat the comment from @Bernhard.

Start and Stop Diff of two files opened in 2 Windows (works in both, vertical and horizontal split):

:windo diffthis
:windo diffoff

this can be shortened to either

:windo difft
:windo diffo

or

:windo difft
:diffo!

Be aware that opened windows for showing plugin content lead to issues. So close stuff like NERDtree, minibufexplorer++ etc before.

Custom commands: To ease up things you can add custom commands to your ~/.vimrc:

command! Difft [ClosePluginWindow |] windo diffthis
command! Diffo windo diffoff

with [ClosePluginWindow |] being optional to close plugin windows you usually use. For NERDtree e.g. this would be NERDTreeClose |.

Credits go to @cxw and @Jordi Freixa.

View more solutions

Comments

[Zaid]

Is there a way to lock scrolling between the two windows?

[maxschlepzig]

Yes, check out vimdoc.sourceforge.net/htmldoc/options.html#%27scrollbind%27 - with vimdiff it is the default.

[Bernhard]

:windo :diffthis can be used instead of the last three commands.

[djangofan]

I usually use "diff file1 file2" on the command line.

[Dave]

This does not answer the question. The question was how to compare two different files in vim. This answer describes how to split the view of a single file vertically. Which shows two views of the same file. This answer also suggests using vimdiff, which DOES provide a solution to comparing two files in a vim-like environment, however again, not what op was asking for. Question was "Is it possible to view two files side-by-side in Vim", not in vimdiff.

[Dave]

This should be the correct answer. :vs otherfile literally compares two files in vim, not vimdiff.

[maxschlepzig]

@Dave well, this answer assumes that the reader already knows how to open a file in Vim (e.g. using :e). With that knowledge it's pretty obvious that you can open the file you want to compare when navigating to the other site. Funny, how an answer that allegedly doesn't answer the question was accepted and currently is the highest voted one.