Modify UPN using "E-Mail" field on general tab

Aug 17, 2014 at 7:27 PM
Need to use the email field on the general tab to modify the UPN. Issues is I am not sure how to just pull the first.last and leave off the @email.com. The names in AD cannot be used as they have spaces and special characters. The email field minus the @email.com has the exact info needed.
Anyone know how to achieve this?