title: Identifying received signal name in Bash
body: <p>When a signal is received, I can execute some commands using <code>trap</code>. Example:</p>
  
  <pre><code>trap 'echo hello world' 1 2
  </code></pre>
  
  <p>If any of the signals specified is received, the hello world' is displayed. </p>
  
  <p>But how can I print/identify the received signal name?</p>