Adding "Mail" to all users in NetInfo/LDAP databas

Hi folks, How can I write a script (sh or whatever) to... 1) check each user in our NetInfo listing for existance of a "mail" tag 2) If it doesn't exist, add a "mail" tag to that user and populate with their e-mail address (shortname@mmc.school.nz) I want to set this up as a cron job to run once each week to account for any new users, etc. I know how to do this manually using netInfo manager, just don't want to do this for all 1000+ users in our database. cheers, Kent Lendrum HOD Computer Studies Mount Maunganui College New Zealand