title: npm Gulp dependencies missing, even after running npm install
body: <p>I have a project that uses Gulp. I deployed my project onto my Ubuntu server and now want to compile the assets (which is all my gulpfile does at the moment). Having installed Node and npm I run <code>npm install</code> from my project's root to install the dependencies. The package.json reads as follows:</p>
  
  <pre><code>  ...},
    "devDependencies": {
      "bower": "&gt;=1.3.12",
      "gulp": "^3.8.10",
      "gulp-concat": "^2.4.3",
      "gulp-less": "^2.0.1",
      "gulp-minify-css": "^0.4.3",
      "gulp-notify": "^2.2.0",
      "gulp-rename": "^1.2.0",
      "gulp-uglify": "^1.1.0"
    }...
  </code></pre>
  
  <p>Upon then inspecting the <code>node_modules</code> folder in my project root I can see directories for each of the dependencies indicating they were installed. However when I run <code>gulp</code> I get npm errors such as the below:</p>
  
  <pre><code>Error: Cannot find module 'through2'
      at Function.Module._resolveFilename (module.js:338:15)
      at Function.Module._load (module.js:280:25)
      at Module.require (module.js:364:17)
      at require (module.js:380:17)
  </code></pre>
  
  <p>These seem to be dependencies of the my project's dependencies (as they are not referenced in my gulpfile), but why hasn't npm installed them?</p>
  
  <p>I can manually install each one as the error arises but I then get another similar error for the next missing dependency.</p>
  
  <p>How can I solve this?</p>