Lesson 2: Managing Users and Groups

Superuser (root)

The account with full control over the Linux system

Root risk

Can change, delete, or break anything on the system

Why avoid root login

Security risk and potential for accidental damage

sudo

Run a command with temporary admin privileges

sudo benefit

Safer because it limits admin access to one command

su

Switch to another user account

su -

Switch to root with full environment (more powerful and risky)

Safer admin method

sudo

User account

An identity used to access the system

UID

A unique number that identifies a user in Linux

Create user

useradd username

Set password

passwd username

Delete user

userdel username

Login requirement

A user must have a password to log in

Group

A collection of users managed together

Group purpose

Manage permissions for multiple users at once

Create group

groupadd groupname

Add user to group

usermod -aG groupname username

Delete group

groupdel groupname

Query (Linux)

Checking information about users or groups

whoami

Shows current logged-in user

groups

Shows groups the current user belongs to

/etc/passwd

File that stores all users

/etc/group

File that stores all groups

User profile

Settings that load when a user logs in

Profile purpose

Customize environment and behavior for users

.bashrc

A file that controls user environment and commands

.profile

A file that sets login environment settings

Profile example

Run commands automatically at login