title: sed replace single/double quoted text?
body: <p>Having some difficulty in replacing some single/double quoted text with <strong>sed</strong> and was wondering what's the correct method for these 2 examples</p>
  
  <p>to change Memached.ini file contents from</p>
  
  <pre><code>[server]
  server[] = "localhost:11211"
  </code></pre>
  
  <p>to </p>
  
  <pre><code>[server]
  server[] = "localhost:11211"
  server[] = "localhost:11212"
  </code></pre>
  
  <p>and to change memcache.php file contents for these lines from</p>
  
  <pre><code>define('ADMIN_USERNAME','username');    // Admin Username
  define('ADMIN_PASSWORD','password');    // Admin Password
  
  $MEMCACHE_SERVERS[] = 'mymemcache-server1:11211'; // add more as an array
  $MEMCACHE_SERVERS[] = 'mymemcache-server2:11211'; // add more as an array
  </code></pre>
  
  <p>to</p>
  
  <pre><code>define('ADMIN_USERNAME','myusername');  // Admin Username
  define('ADMIN_PASSWORD','mypassword');      // Admin Password
  
  $MEMCACHE_SERVERS[] = 'localhost:11211'; // add more as an array
  $MEMCACHE_SERVERS[] = 'localhost:11212'; // add more as an array
  </code></pre>
  
  <p>I tried for example</p>
  
  <pre><code>sed -i 's/'ADMIN_USERNAME','memcache'/'ADMIN_USERNAME','u'/g' /var/www/html/memcache.php
  </code></pre>
  
  <p>while command runs, memcache.php file isn't changed at all ?</p>