I have had very bad luck with installing and using NodeJS on the MacOSX.  I originally downloaded the MacOSX version from https://nodejs.org/en/ and it is just ever so slightly different from what is used on linux that many commands did not work for me.

Instead, I installed it using homebrew and no longer had any problems with it.  Homebrew is a little difficult to configure initially - but once configured it is easy to use.  I followed the instructions from: http://shapeshed.com/setting-up-nodejs-and-npm-on-mac-osx/  which includes a link to installing homebrew.

What it basically boils down to is: install homebrew

From the command line execute "brew install node"

Then install everything else using the instructions from the various tools.  Ie 

npm install -g grunt

npm install -g yo

Without homebrew, you often need to run sudo:

sudo npm install -g grunt

And a number of the nodejs install packages refuse to install if your using sudo..