title: Some random questions about Plugin Dev for IntelliJ
body: <p>I am new to IntelliJ Plugin Development and would like to write a little Plugin for a C# Framework I am using. The Plugin would be for the Rider IDE. The things I would like to know are:</p>
  
  <ul>
  <li>How do I execute Code after a project was opened in the IDE?</li>
  <li>How do I run a command in the background and display the output of that program in a window that is docked in the bottom like the Terminal Window. Alternativley: how do I open a new terminal and run a command in it?</li>
  <li>How do I run Code when a file is saved and how do I check if the class that lives inside this files Implements a certain interface?</li>
  <li>How do I add settings to my plugin?</li>
  <li>How do I add a new Option to the "Mark Directory As" submenu and how do I acces all directories marked as a certain type?</li>
  <li>How do I find out on which OS we are currently running? </li>
  </ul>
  
  <p>If anybody could point me in the right way on any of these questions, it would mean the world to me :) Thank you very much!</p>