title: how can I recognize which OS I am on in a bash script
body: <p>I need to make script that behaves differently per system. Today it is possible to run bash even on microsoft windows, mac, linux, hp-ux, solaris etc...</p>
  
  <p>How can I determine which of these operating systems I am on? I don't need exact version, I just need to know if I am on windows, linux, solaris...</p>