Here in CS we have to deal with some very old accounts where we don't want their user-ids (UIDs) and group-ids (GIDs) changed from what they've always been (isn't legacy support wonderful:-)). This means that other than account "nobody" we don't want any of the new system, software and user IDs to conflict with our current legacy IDs. Therefore we want to modify the newly installed OS installation so none of its IDs are between 100 and 10^9. Also we want to modify "/etc/adduser.conf" so adduser will not create new identities between 100 and 10^9.