I really don't know why scripts need to be involved. That means you can only run it once, and next time, you need to get that script again and run it again. You don't have a clean export or anything like that. Just create a report for it so you can always call it (and also people without access to scripts can).
OOB there is a related list 'User -> Manager (sys_user.manager)'. That means you can just create a simple list report on the sys_user table with a related list condition where related list table = User -> Manager and select 'Greater than or Equal to 1' as condition. This will show you every user that has at least one person he or she manages:
