title: installing npm modules on ubuntu gives me an error
body: <p>i got the following error when i tried to install an npm package called sharp.</p>
  
  <pre><code>sudo npm install -g sharp
  
  &gt; sharp@0.21.0 install /usr/local/lib/node_modules/sharp
  &gt; (node install/libvips &amp;&amp; node install/dll-copy &amp;&amp; prebuild-install) || (node-gyp rebuild &amp;&amp; node install/dll-copy)
  
  info sharp Downloading https://github.com/lovell/sharp-libvips/releases/download/v8.7.0/libvips-8.7.0-linux-x64.tar.gz
  ERR! sharp EACCES: permission denied, open '/usr/local/lib/node_modules/sharp/19229-libvips-8.7.0-linux-x64.tar.gz'
  ERR! sharp Please see http://sharp.pixelplumbing.com/page/install
  gyp WARN EACCES user "root" does not have permission to access the dev dir "/home/areahints/.node-gyp/8.10.0"
  gyp WARN EACCES attempting to reinstall using temporary dev dir "/usr/local/lib/node_modules/sharp/.node-gyp"
  gyp WARN install got an error, rolling back install
  gyp WARN install got an error, rolling back install
  gyp ERR! configure error 
  gyp ERR! stack Error: EACCES: permission denied, mkdir '/usr/local/lib/node_modules/sharp/.node-gyp'
  gyp ERR! System Linux 4.15.0-39-lowlatency
  gyp ERR! command "/usr/bin/node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
  gyp ERR! cwd /usr/local/lib/node_modules/sharp
  gyp ERR! node -v v8.10.0
  gyp ERR! node-gyp -v v3.8.0
  gyp ERR! not ok 
  npm ERR! code ELIFECYCLE
  npm ERR! errno 1
  npm ERR! sharp@0.21.0 install: `(node install/libvips &amp;&amp; node install/dll-copy &amp;&amp; prebuild-install) || (node-gyp rebuild &amp;&amp; node install/dll-copy)`
  npm ERR! Exit status 1
  npm ERR! 
  npm ERR! Failed at the sharp@0.21.0 install script.
  npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
  
  npm ERR! A complete log of this run can be found in:
  npm ERR!     /home/areahints/.npm/_logs/2018-11-18T16_14_58_685Z-debug.log
  </code></pre>
  
  <p>running the same code without sudo throws a different error</p>
  
  <pre><code>npm install -g sharp
  npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
  npm ERR! path /usr/local/lib/node_modules
  npm ERR! code EACCES
  npm ERR! errno -13
  npm ERR! syscall access
  npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
  npm ERR!  { Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
  npm ERR!   stack: 'Error: EACCES: permission denied, access \'/usr/local/lib/node_modules\'',
  npm ERR!   errno: -13,
  npm ERR!   code: 'EACCES',
  npm ERR!   syscall: 'access',
  npm ERR!   path: '/usr/local/lib/node_modules' }
  npm ERR! 
  npm ERR! The operation was rejected by your operating system.
  npm ERR! It is likely you do not have the permissions to access this file as the current user
  npm ERR! 
  npm ERR! If you believe this might be a permissions issue, please double-check the
  npm ERR! permissions of the file and its containing directories, or try running
  npm ERR! the command again as root/Administrator (though this is not recommended).
  </code></pre>
  
  <p>I have similar issues with node-expat, iconv and libxmljs. I have tried installing all dependencies and dev-dependencies and retried to no avail.</p>