title: PHP functions not defined in command line
body: <p>It seems quite strange that some function is defined when it is called by web browsers,
  but it becomes undefined in command line mode.</p>
  
  <p>For example,</p>
  
  <pre><code>&lt;?php
  echo function_exists('mb_detect_encoding') ? 'yes' : 'no';
  ?&gt;
  </code></pre>
  
  <p>When it runs in the browsers, it prints "yes" which means this function is already defined.</p>
  
  <p>But when I run this piece of code in command line, it prints "no"</p>
  
  <p>Why? what settings did I miss in command line mode?</p>