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..