REGEX - PROBLEM

Quoting Newb Newb <rails-mailing-list@andreas-s.net>:

Helloo..   how to make this below regular expression not to accept _ anywhere in the string   /^[a-zA-Z0-9.]+[\w\s]*$/   how can i modify it..   Any Advices or Suggesions...   Thanks

if s =~ /_/   reject string end