title: $PATH in vim is different from which in shell? (Mac OSX)
body: <p>As you know that the ctags in OSX is a basic version, and I install a full version of ctags using homebrew, but when I wanna use it in Vim's command mode, it always ran the basic one. So I checked the $PATH var in Vim's command mode, like <code>!echo $PATH</code>, and it showed that <code>/usr/local/bin</code> followed the <code>/usr/bin</code>, which was different from the shell environment $PATH, so please kindly tell me how to fix this， many thanks!.
  BTW, I changed the $PATH in vimrc file, but it only affected the $PATH if I type the command <code>echo $PATH</code> in Vim's command mode, not <code>!echo $PATH</code>.</p>