title: shell does not keep bold format when using mail command
body: <p>I use shell script as below to get the string partly bold which works and results in the correct string echo'd in the terminal:  </p>
  
  <pre><code>bold=$(tput bold)
  normal=$(tput sgr0)
  str="${bold}ERROR${normal} detail text"
  echo -e "$str"
  </code></pre>
  
  <p>It does not work together with <code>mail</code> command:</p>
  
  <pre><code>echo -e "$str" | mail -s "daily notification" 123@abc.com
  </code></pre>
  
  <p>I receive an email with "[1mERROR", But not "<strong>ERROR</strong>", anyone know why? </p>