Manual:FixUserRegistration.php

Details
fixUserRegistration.php file is a 2>Special:MyLanguage/Manual:Maintenance scripts|maintenance script to fix the   field. Old user accounts have the   field set to "NULL". This script searches for those users who are affected, and inserts the timestamp from their first edit as an estimation for the registration time into the   field.

This script processes 1000 items in a batch.

Options/Arguments
This script does not take any options or arguments.