title: what does "<()" mean in bash?
body: <p>I'm trying to install RVM. There is a magical command line:</p>
  
  <pre><code>bash &lt; &lt;(curl -s https://rvm.io/install/rvm)
  </code></pre>
  
  <p>I know what bash and curl are. I know the first <code>&lt;</code> is the I/O redirection. But what does <code>&lt;()</code> syntax mean?</p>
  
  <p>What's the difference between this command and </p>
  
  <pre><code>bash &lt; `curl -s https://rvm.io/install/rvm`
  </code></pre>
  
  <p>?(the latter command doesn't work)</p>