title: mailx: "send-mail: illegal option -- a" while attempting to send file attachment
body: <p>Our production server has been retired and now we are using a hosted system running Redhat GNU/Linux.</p>
  
  <p>We had many scripts using mutt to send file attachments but they're failing now since mutt is not installed on our servers (The sysadmin policy is that mutt is not secure so it will not be installed)</p>
  
  <p>I have tried using mailx but to no avail. When I do</p>
  
  <pre><code>echo "this is my email body"| mailx -s "this is my email subject" "email@xyz.com" -a "filename.csv"
  </code></pre>
  
  <p>I get </p>
  
  <pre><code>$ send-mail: illegal option -- a
  </code></pre>
  
  <p>"filename.csv" exist and it is local to the directory I run the command from.  Of course, when I do</p>
  
  <pre><code>mailx -s "this is my email subject" "email@xyz.com" &lt; "filename.csv"
  </code></pre>
  
  <p>It works but it embeds the file attachment in the email body. Users do not want that.</p>
  
  <p>What am I doing wrong?</p>