Chapter 7

user info stored in 2 config files

- /etc/default/useradd ;text file read by all users, shell, skel, groups /etc/login.defs(also read by all users; default PATH settings, passwd changes, UID and GID ranges

configuration files, user database

- /etc/passwd - /etc/shadow

/etc/passwd, fields

Username (lower-case reccomended), password (encrypted), user identifier(UID), Group identifier (GID), GECOS, Home directory, Shell

/etc/group file

config file that stores group info, can be read by all, includes group name, password group identifier, list of members

/etc/shadow

configuration file containing passwords and password expiration information for all User Accounts. Can only be read by the root user.

/etc/passwd

contains user account information; ea. entry has 7 fields separated by colons; everyone has permission to view this file's contents (world-readable)

yast2 users

modify users with YaST, can add/change user data, detials, password settings, plug-ins

Authentication

the process of verifying someone's identity by checking his or her username and password against a central user database.

'usermod' command

use to change user account info - only done by root user

'groupadd' command

use to create a group account

'userdel' command

use to delete user accounts and remove all entries from user database files (/etc/passwd and /etc/shadow

'chage' command

use to list and modify password info for user accts, add'l privileges for root user

'groupmod' command

use to modify existing groups

/etc/shadow, fields

username, encrypted password, last password change, minimum (b4 passwd changed), expiration, warning, disabled, disabled date, reserved