- uid : cat /etc/passwd - gid : cat /etc/group - create group : groupadd -g {gid} dba - create user : useradd -u {uid} -g dba -m -d /home/oracle oracle - change gid : groupmod -g {new gid} dba find / -group {old gid} -exec chgrp -h dba {} \; - change uid : usermod -u {new uid} oracle find / -user {old uid} -exec chown -h oracle {} \; - change group usermod -g dba oracle - delete uid : userdel -r..