Q:

where is vimfiles directory on mac OS?

I am a new user of mac OSX, I found there is no vimfiles directory under /usr/share/vim, but directory vim73 is there. this vim was shipped with OS and I didn't install it.
vimfiles was used for command files, plugins, which won't be affect by vim updates, but vim73 is only for current version, if I install vim74, then all files under vim73 won't be used any more.

A:

Just create a .vim directory in your home folder:
$ cd
$ mkdir .vim

This will used by every version of VIM.  This is explained under
:help vimfiles

