title: can I use pipes to communicate with existing application?
body: <p>I was reading about pipes today, it seems an interesting for me to use it or to start about it.
  but it's written there that the processes should be like a parent and child or client server and the communication will be between them. </p>
  
  <p>there are some things I don't understand and before start I should be sure about them.</p>
  
  <p>If I have a running process for example on my machine, and I want to send message to it, of course I can't control it, so how can I make it respond to my messages??
  should I create the client and server and run them both?? 
  Or the running process application can be a server for example and I can send some events to it??</p>
  
  <p>if you can help me in this :)</p>
  
  <p>thanks :)</p>