Create linux user

To create a new linux user type:

adduser <name_of_the_user>

Enter all user information + password

No password login

If you want to create a user where it is not possible to log in with any password type:

adduser --disabled-password <name_of_the_user>

Login is still possible starting from the root user with:

su <name_of_the_user> -

Create sudo user

You can add a existing user to the sudo group with:

usermod -aG sudo <name_of_the_user>

No sudo password required

To allow executing the sudo command without entering the password execute

visudo

This opens an editor. Change the line %sudo    ALL=(ALL:ALL) ALL to %sudo   ALL=(ALL:ALL) NOPASSWD: ALL Now all users in the sudo group can execute sudo commands without entering password.