title: where is SIGHUP from? (sshd forks a child to create a new session, kill this child and all processes in the session dies)
body: <p>sshd forks a child process to create a new session.
  here is the output(partial) of pstree:</p>
  
  <pre><code>sshd(1230) -- sshd(1234) -- bash
             (...)    
               |- sshd(1235) -- bash -- a.out -- a.out
  </code></pre>
  
  <p>After running "kill -9 1235" , a.out dies (the signal captured is SIGHUP)</p>
  
  <p>Why?</p>
  
  <p>tks!</p>