title: sed command to replace php.ini memory_limit
body: <p>I have php.ini with memory_limit = 128M
  I would like to replace this with sed command.</p>
  
  <p>I had try this, and it does not work</p>
  
  <pre><code>sed -i '' 's/memory_limit\s*=\s*\d*M/memory_limit = 1024M/g' ~/Desktop/php.ini 
  </code></pre>
  
  <p>any idea why?
  I copy it to desktop so it does not tinker the original one before it actually working</p>