================== Linux System Admin ================== A user has a username, primary group and additional group. /etc/passwd Contains one line for each user account. /etc/shadow Contains the password information in encrypted formatfor the system's accounts and optional account aging information. /etc/group Defines the groups on the system. /etc/default/useradd This file contains a value for the default group, if none is specified by the useradd command. /etc/login.defs This file defines the site-specific configuration for the shadow password suite stored in /etc/shadow file. ============================================= ================================ ================================ ====================================== Task Format Example - ============================================= ================================ ================================ ====================================== Add user to existing or new group ``useradd -G `` Add User to Primary Group ``useradd -g `` Add group ``groupadd `` Set user password ``passwd`` `` Add User to Existing Group as secondary group ``usermod -a -G `` ``usermod -a -G `` Group can be a list of multiple groups ============================================= ================================ ================================ ====================================== Add User as Sudo:: su visudo Add the user ``uname`` to the sudo group, this will permit them to *sudo*.:: usermod -a -G sudo uname View Groups:: cat /etc/group Get info on user:: id