passwd
Manage user passwords
chage
Manage password settings
w
Displays current users on the system
who
Displays current users on the system
useradd
Adds a user
usermod
Modifies a user
userdel
Deletes a user
id
Gather and display account information
groupadd
Create a new group
groupmod
Modifies an existing group
groupdel
Deletes an existing group
su
Switch user to specified user/group account
sudo
exercise delegated privileges
pkexec
Allows an authorized user to execute an action. Uses PolicyKit