How to Add a User with Root Privileges on Ubuntu 18.04

What is root?

Root is the all-powerful account on a Linux server. It can change or delete anything. One wrong command can break the server. A safer way is to use a normal user. That user borrows root power only when it types sudo before a command. Sudo means "do this as the boss".

Steps

Log in to your server as root with SSH. SSH is a safe way to type commands on a faraway server. Your welcome email has your login details.
Create the new user. Replace sam with the name you want:
```
adduser sam
```
This command makes the user and asks you for a password.
Type a strong password and press Enter. Type it again to confirm. A strong password is long and mixes letters, numbers and symbols.
Fill in the extra questions, such as full name. You can press Enter to skip them.
Type Y when it asks if the information is correct.
Give the user admin rights:
```
usermod -aG sudo sam
```
This command adds the user to the sudo group. A group is a list of users who share the same rights.
Check the group:
```
groups sam
```
You should see sudo in the list.

Test the new user

Switch to the new user:
```
su - sam
```
Run a test command with sudo:
```
sudo ls /root
```
This command lists the root folder. Only admins may see it.
Type the user's password. If you see a file list, it works.

Next time, log in straight as sam over SSH.

Remove sudo rights

To take admin power away, run this as root:

deluser sam sudo

This command removes the user from the sudo group, but keeps the account.

Tip: Ubuntu 18.04 is an older release. Newer Ubuntu versions use the same commands.

Quick recap

Do not use root for daily work.
Make a user with adduser.
Add the user to the sudo group with usermod -aG sudo.
Test with sudo before you log out as root.