Create User Account
adduser USERNAME
Delete User Account
deluser USERNAME
Additional Options:
apt-get install perl-modules
deluser --remove-all-files USERNAME
deluser --backup USERNAME
deluser --remove-all-files --backup USERNAME
Create Group
addgroup GROUPNAME
Delete Group
delgroup GROUPNAME
delgroup --only-if-empty GROUPNAME
Add user to a group
adduser USERNAME GROUPNAME
Remove user from a group
deluser USERNAME GROUPNAME
Lock User Account
passwd -l USERNAME
Unlock User Account
passwd -u USERNAME
List Age
chage -l USERNAME
Change Age
chage -E 2007/09/01 USERNAME
Print UID, GID
id USERNAME