title: Regular expressions middle of string
body: <p>How I can get part of SIP URI?
  For example I have URI <code>sip:username@sip.somedomain.com</code>, I need get just <code>username</code> and I use <code>[^sip:](.*)[$@]+</code> expression, but appeared result is <code>username@</code>. How I can exclude from matching <code>@</code>?</p>