title: How can I run composer without user interaction?
body: <p>I'm trying to run composer install on a cakephp installation, however it asks the user if they want to they want to set folder permissions:</p>
  
  <p>Note, this is an example. In production the <code>composer install</code> command will happen automatically via CI or whatever:</p>
  
  <pre><code>John:$ composer install
  Loading composer repositories with package information
  Installing dependencies (including require-dev) from lock file
  Nothing to install or update
  Generating autoload files
  &gt; Cake\Composer\Installer\PluginInstaller::postAutoloadDump
  &gt; App\Console\Installer::postInstall
  Set Folder Permissions ? (Default to Y) [Y,n]?
  </code></pre>
  
  <p>This is great, but there are times where I want to specify 'yes' from the command line so that my docker install doesn't require interaction, and so that our deployment process can work (there is no user involved!) I've tried several things, inspected the code and googled like mad to no avail.</p>
  
  <p>I'm guessing there's an environment variable I can set to make it default to yes / quiet, but I just can't find what it is.</p>