#simple user add
sudo useradd username
#add user and add him into a group
sudo useradd username -G groups
#with password
sudo useradd username -p P@ssw0rd
Задать/сменить пароль пользователя:
sudo passwd username
#force user password change on next logon
sudo chage username -m 0
Добавление пользователя в группу:
sudo usermod -aG groupname username
#view groups user belongs to
groups username