>>> "abc..def" !~ /\.\./
=>> false

I don't think that
  "abc..def" !~ /\.\./
is a regular expression.

   /\.\./
is a regular expression.


Basically ... I need something that will work in a Rails validates_format_of

  # Reject if the email address has two periods in a row
  validates_format_of     :email,
                        # See http://en.wikipedia.org/wiki/E-mail_address
                        :with => ????,
                        :message => 'invalid email format'