title: How do get exit code from Ruby's Process.fork()?
body: <p>As it says on the tin</p>
  
  <pre><code>pid = Process.fork do
    exit 25
  end
  </code></pre>
  
  <p><code>pid</code> seems positively useless besides telling me what actual system process number the fork ran under. Will <code>Thread</code> be more useful?</p>