Unable to install Ionic with npm? (Mac OSX El Capitan 10.11.2)

I am trying to install Ionic using npm, on my mac, running OSX El Capitan 10.11.2.

sudo npm install -g cordova ionic

Cordova is already installed, and I definitely entered my password correctly. Here are the error messages and logs:

Last login: Sun May  1 18:41:17 on ttys001
egaumbp:~ gg$ sudo npm install -g cordova ionic
Password:
/usr/local/bin/cordova -> /usr/local/lib/node_modules/cordova/bin/cordova
/usr/local/bin/ionic -> /usr/local/lib/node_modules/ionic/bin/ionic

> node-sass@3.4.2 install /usr/local/lib/node_modules/ionic/node_modules/node-sass
> node scripts/install.js

shell-init: error retrieving current directory: getcwd: cannot access parent directories: Permission denied
path.js:424
var path = (i >= 0) ? arguments[i] : process.cwd();
                                             ^

Error: EACCES: permission denied, uv_cwd
at Error (native)
at Object.posix.resolve (path.js:424:50)
at startup (node.js:96:32)
at node.js:968:3
npm ERR! Darwin 15.2.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "-g" "cordova" "ionic"
npm ERR! node v4.4.1
npm ERR! npm  v2.14.20
npm ERR! code ELIFECYCLE

npm ERR! node-sass@3.4.2 install: `node scripts/install.js`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the node-sass@3.4.2 install script 'node scripts/install.js'.
npm ERR! This is most likely a problem with the node-sass package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     node scripts/install.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs node-sass
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! 
npm ERR!     npm owner ls node-sass
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /Users/gg/npm-debug.log
egaumbp:~ gg$ 

Is there a solution?

Have you tried this? Ionic install issue osx