title: "npm -g yarn" gives "permission denied, symlink..." but the proper permissions do exists
body: <p>I need to install yarn without sudo. I do this:</p>
  <pre><code>$ npm install -g yarn
  </code></pre>
  <p>and I get this:</p>
  <pre><code>npm ERR! code EACCES
  npm ERR! syscall symlink
  npm ERR! path ../lib/node_modules/yarn/bin/yarn.js
  npm ERR! dest /usr/bin/yarn
  npm ERR! errno -13
  npm ERR! Error: EACCES: permission denied, symlink '../lib/node_modules/yarn/bin/yarn.js' -&gt; '/usr/bin/yarn'
  npm ERR!  [OperationalError: EACCES: permission denied, symlink '../lib/node_modules/yarn/bin/yarn.js' -&gt; '/usr/bin/yarn'] {
  npm ERR!   cause: [Error: EACCES: permission denied, symlink '../lib/node_modules/yarn/bin/yarn.js' -&gt; '/usr/bin/yarn'] {
  [.........]
  </code></pre>
  <p>But:</p>
  <pre><code>ls -al /usr/lib/node_modules/
  
  drwxr-xr-x  5 user1 user1  4096 Sep 15 05:13 .
  drwxr-xr-x 63 root  root  32768 Sep 14 15:18 ..
  drwxr-xr-x  9 user1 user1  4096 Sep 14 14:48 node-gyp
  drwxr-xr-x  9 user1 user1  4096 Sep 15 04:22 npm
  drwxr-xr-x  7 user1 user1  4096 Sep 14 14:48 semver
  </code></pre>
  <p>And</p>
  <pre><code>$ ls -ald /usr/lib/node_modules/
  drwxr-xr-x 5 user1 user1 4096 Sep 15 05:13 /usr/lib/node_modules/
  </code></pre>
  <p>Why and how to fix it?</p>