Some systems assign users a UID>100, others UIDs are >500, or even 1000. Look what is the lowest UID for a regular user in your system. Let say it is above 1000, like mine.
Code:
cat /etc/passwd | awk -F: '{if ($3>1000) print $0}' | grep -Ev "nfsnobody|otherunwanteduser1|otherunwanteduser2" | awk -F: '{printf "%s - real name: %s\n", $1, $5}'