Create new user
sudo useradd username
Create user with home directory
sudo useradd -m username
Create user with specific shell
sudo useradd -m -s /bin/bash username
Set user password
sudo passwd username
Delete user
sudo userdel username
Delete user and home directory
sudo userdel -r username
Modify user
Add user to sudo group:
sudo usermod -aG sudo username
Add user to multiple groups
sudo usermod -aG group1,group2 username
Change user's home directory
sudo usermod -d /new/home/path username
Change user's shell
sudo usermod -s /bin/zsh username
Lock user account
sudo usermod -L username
Unlock user account
sudo usermod -U username
Create new group
sudo groupadd mygroup
Delete group
sudo groupdel mygroup
View user's groups
groups username
View current user's groups
groups
List all users
cat /etc/passwd
List all groups
cat /etc/group
View user information
id username
Switch to another user
su - username
Run command as another user
sudo -u username command