title: scheduling a command to execute right after a *running* command finishes?
body: <p>Sometimes I will run a command 'foo', and it takes way longer than I expect it to. If I were to rerun it, I'd probably do something like:</p>
  
  <pre><code>foo &amp;&amp; mail -s "foo is done" me@com.com
  </code></pre>
  
  <p>..so it emails me when it's done and I can go do something else. But what if I already launched foo and I don't want to restart it? Is there a way to append the &amp;&amp; mail... part to the original command, so to speak?</p>
  
  <p>Thanks.</p>