title: mailx change sender name
body: <p>I understood that for changing sender's name with <code>mailx</code> I should do the following:</p>
  
  <pre><code>mailx -r newmail@mail.com -s "some subject" my@email.com
  </code></pre>
  
  <p>But when I do that, I get:</p>
  
  <pre><code>mailx: invalid option -- r
  Usage: mail [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...
              [-- sendmail-options ...]
         mail [-iInNv] -f [name]
         mail [-iInNv] [-u user
  </code></pre>
  
  <p>Does anyone knows what's happening? 
  thanks,</p>