偶然间发现了git 2.9可以支持更好看的Diff功能了，如下：

只好先update brew

brew update 

再更新git

brew upgrade git

然后就看着它更新了：

==> Upgrading 1 outdated package, with result:
git 2.9.0
==> Upgrading git
==> Downloading https://homebrew.bintray.com/bottles/git-2.9.0.el_capitan.bottle.tar.gz

接着，需要link这个工具：

ln -s /usr/local/Cellar/git/2.9.0/share/git-core/contrib/diff-highlight/diff-highlight /usr/local/bin/

然后配置:

git config pager.diff 'diff-highlight | less'

也可以配置到其他几个不同的命令:

$ git config pager.log 'diff-highlight | less'
$ git config pager.show 'diff-highlight | less'
$ git config pager.diff 'diff-highlight | less'

顺便的：

git config interactive.diffFilter diff-highlight