title: Switch php versions on commandline ubuntu 16.04
body: <p>I have installed php 5.6 and and php 7.1 on my Ubuntu 16.04</p>
  <p>I know with Apache as my web server, I can do</p>
  <pre><code>a2enmod php5.6 #to enable php5
  a2enmod php7.1 #to enable php7
  </code></pre>
  <p>When I disable php7.1 in Apache modules and enable php 5.6, Apache recognizes the change and uses php 5.6 interpreter as expected.</p>
  <p>But when I run internal php web server from the commandline:</p>
  <pre><code>php -S localhost:8888
  </code></pre>
  <p>php handles requests using php 7. So how do I switch between php 5.6 and php 7.1 in the command line ?</p>