Manage Local Users and Groups

User and Group Concept

User

A user is an account used to log in and operate a Linux system.

User Information Commands

• id → Show details of the currently logged-in user.
• id {username} → Show details of a specific user.
• /etc/passwd → Stores information about all system users.

Super User (Root)

• UID: 0
• Other Name: root

Regular User

• Non-root users created for daily tasks.

System User

• Used for system services and processes, not for login.

Group

A group is a collection of users that share permissions.

Group Information Commands

• gid → Show the group ID of the current user.
• /etc/group → Stores information about groups, including supplementary groups.

Primary Group

• The default group assigned to a user when created.

Supplementary Groups

• Additional groups a user can be part of for extra permissions.

Gain Superuser Access

Switch user account

sudo su - user2 #switch user without knowing user2 password
su - #try to login as root user
su - user3 #swtich to user3 with his password

Run command with root

sudo

wheel group use for give administrator access to users.

Get interactive Root shell with sudo

sudo -i