title: What is the between < and cat at a UNIX shell?
body: <p>I'm studying linux, and found that the input operator symbol '&lt;' appears to work the same as the command 'cat'.</p>
  
  <pre><code>➜  /tmp echo "test" &gt; testfile
  ➜  /tmp cat testfile 
  test
  ➜  /tmp &lt;testfile 
  test
  </code></pre>
  
  <p>I want to know what the difference is between them.</p>