title: What does tr -ct do?
body: <p>I am confused about the execution sequence of <code>tr</code> options.</p>
  
  <p>For example, there is a command like this:</p>
  
  <pre><code>echo 123 | tr -ct '\n' '0'
  </code></pre>
  
  <p>How does this execute? Is <code>-c</code> executed first or <code>-t</code>?</p>
  
  <p>And I am also confused about the result of this command.
  I thought <code>-c</code> is executed first, and the result is <code>123</code>, then <code>-t</code> will be executed , and the result is <code>023</code>, and the final is <code>023\n</code>. But it's wrong, right answer is <code>123\n</code>,
  I don't know why, could someone tell me?</p>