php - Recursive subpattern regex -

I want to read the name of the server from a nginx config file.
Then I need to rotate a line again:
server_name this.com www.this.com someother-example.com;

I am using PHP's preg_match_all and I've tried different things so far:
/ ^ (?: Server_name [\ s] *) (?: (.: * (?: \ S *)) * $ / m : which gives me nothing / ^ (?: Server_name [\ s] *) ((?: (? :. *) (?: \ S *)) *); $ / M gives me this www www. This.com someother-example.com

but I can not find the right to list the domain as a different value

  [0 = & gt; 'This.com', 1 = & gt; 'Www.this.com', 2 = & gt; Perhaps, one of you know?  
 Thank you!   
 
  
 
 As your uncle of Bob wrote: "post-text" itemprop = "text"> 
:  
  (?: Server_name | \ G (?! ^)) \ S * \ K [^; | \ S] +  
 
 What a move!