title: npm install not working, throwing errors
body: <p>I am trying to install yo and a few other packages in nodejs, however I keep getting errors. I am new to node so I am a little lost. 
  I am running Mac OS X 10.10.3. The command I am using is </p>
  
  <pre><code>sudo npm install --global yo
  </code></pre>
  
  <p>Doing this gives me the following errors. </p>
  
  <pre><code>&gt; spawn-sync@1.0.13 postinstall /usr/local/lib/node_modules/yo/node_modules/cross-spawn/node_modules/spawn-sync
  &gt; node postinstall
  
  shell-init: error retrieving current directory: getcwd: cannot access parent directories: Permission denied
  node.js:720
      var cwd = process.cwd();
                        ^
  Error: EACCES, permission denied
      at Error (native)
      at Function.startup.resolveArgv0 (node.js:720:23)
      at startup (node.js:63:13)
      at node.js:814:3
  npm ERR! Darwin 14.3.0
  npm ERR! argv "node" "/usr/local/bin/npm" "install" "--global" "yo"
  npm ERR! node v0.12.7
  npm ERR! npm  v2.11.3
  npm ERR! code ELIFECYCLE
  
  npm ERR! spawn-sync@1.0.13 postinstall: `node postinstall`
  npm ERR! Exit status 1
  npm ERR! 
  npm ERR! Failed at the spawn-sync@1.0.13 postinstall script 'node postinstall'.
  npm ERR! This is most likely a problem with the spawn-sync package,
  npm ERR! not with npm itself.
  npm ERR! Tell the author that this fails on your system:
  npm ERR!     node postinstall
  npm ERR! You can get their info via:
  npm ERR!     npm owner ls spawn-sync
  npm ERR! There is likely additional logging output above.
  
  npm ERR! Please include the following file with any support request:
  npm ERR!     /Users/XXXXXXX/npm-debug.log
  </code></pre>