Subversion diff with vimdiff

Side by side diffs are much more legible and useful than those in unified format or any other linear diff. By default, the svn diff command presents output in the unified format, though it has an option, --diff-cmd, which allows you to specify the program that will perform the diff. Passing vimdiff as the diff command doesn’t work as the options passed by svn diff are a bit complicated:

~/code/perllib/MG$ cat foo.sh
\#!/bin/bash
echo $*
~/code/perllib/MG$ svn diff --diff-cmd foo.sh Proxy.pm
Index: Proxy.pm
-u -L Proxy.pm (revision 21095) -L Proxy.pm (working copy) .svn/text-base/Proxy.pm.svn-base /tmp/svndiff.tmp

Subversion is telling diff to output context (-u), show pretty names for the files (-L) and then the two files to diff. To make this work with vim, we simply need to cut out the extra options. To do so, I wrote a simple script:

\#!/bin/bash
shift 5
vimdiff "$@"

I put that in ~/bin/svnvimdiff and now I can do svn diff --diff-cmd ~/bin/svnvimdiff Proxy.pm and view the diff in vimdiff. Since this is a command I use often, I aliased it in my .bashrc:

alias svndiffvim='svn diff --diff-cmd ~/bin/svnvimdiff'