title: npm install -g download all the dependencies again
body: <p>I have <code>package.json</code> file, that contains 10 dependencies, </p>
  
  <p>Every time I do <code>npm install -g</code>,all the dependencies are downloaded again, and this takes a long time. </p>
  
  <p>Is there a way to take the existing dependencies from the local <code>node_modules</code> directory ? </p>
  
  <p>This is my <code>package.json</code> dependencies:</p>
  
  <pre><code>  "dependencies": {
      "body-parser": "~1.16.0",
      "colors": "^1.1.2",
      "console-stamp": "^0.2.5",
      "cookie-parser": "~1.4.3",
      "dateformat": "^2.0.0",
      "debug": "~2.6.0",
      "express": "~4.14.1",
      "ip": "^1.1.5",
      "jade": "~1.11.0",
      "lodash": "^4.17.4",
      "morgan": "~1.7.0",
      "nodemon": "^1.11.0",
      "promise": "^8.0.1",
      "rand-token": "^0.3.0",
      "random-date-generator": "^1.0.2",
      "restify": "^4.3.0",
      "restify-cookies": "^0.2.2",
      "serve-favicon": "~2.3.2"
    }
  </code></pre>
  
  <p>Thanks,</p>