$ sudo npm install -g ionic
/usr/local/bin/ionic -> /usr/local/lib/node_modules/ionic/bin/ionic

> [email protected] 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:91:32)
    at node.js:962:3
npm ERR! Darwin 15.3.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "-g" "ionic"
npm ERR! node v4.3.1
npm ERR! npm  v2.14.12
npm ERR! code ELIFECYCLE

npm ERR! [email protected] install: `node scripts/install.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] 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 their info via:
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/elviscai/npm-debug.log