title: Kill -INT not working on bash script with trap INT set
body: <p>Consider the following bash script <code>s</code>:</p>
  
  <pre><code>#!/bin/bash
  echo "Setting trap"
  trap 'ctrl_c' INT
  function ctrl_c() {
          echo "CTRL+C pressed"
          exit
  }
  sleep 1000
  </code></pre>
  
  <p>When calling it <code>./s</code>, it will sleep. If you press Ctrl+C it prints the message and exits.</p>
  
  <p>Now call it, open another terminal and kill the corresponding bash pid with
  -INT flag. It does not work or do anything. Why?</p>
  
  <p>Kill without flags works but does not call the ctrl_c() function.</p>