How to Add a User to Sudoers in Ubuntu

What is sudo? The sudo command lets trusted users run special commands with administrator (root) rights. This is helpful when you need to make system changes.

There are two easy ways to let a user run commands with sudo on Ubuntu:

• Add the user to the sudo group
• Give them special permissions in the sudoers file

This guide will show you how to do both in simple steps.

Quick Reference

Task	Command
Add user to sudo group	sudo usermod -aG sudo username
Check user groups	groups username
See user’s sudo permissions	sudo -l -U username
Edit sudoers file safely	sudo visudo
Create sudoers file for user	sudo visudo -f /etc/sudoers.d/username
Test sudo access	sudo whoami

1. Add User to the sudo Group (Easiest Way)

Ubuntu lets anyone in the sudo group run commands as administrator. To give a user these rights, just add them to this group.

Step 1: Open the terminal.

Step 2: Run this command (replace username with the actual user’s name):

sudo usermod -aG sudo username

Step 3: The user needs to log out and log back in for the change to work. Or they can start a new login shell:

su - username

Check the User’s Groups

To see if the user was added to the sudo group, run:

groups username

You should see sudo listed.

Test sudo Access

Switch to the user (if you’re not already) and run:

sudo whoami

If it asks for a password and then shows root, sudo is working!

2. Give User Custom sudo Permissions (Using sudoers File)

Sometimes you want to control exactly what commands a user can run with sudo. That’s when you edit the /etc/sudoers file.

Important: Always edit this file using visudo. It checks for mistakes before saving to prevent breaking sudo access.

Open sudoers File Safely

In the terminal, run:

sudo visudo

This will open the sudoers file in the vi editor by default.

If you prefer the nano editor (which is easier for many users), run:

sudo EDITOR=nano visudo

Give Full sudo Access to a User

At the bottom of the file, add this line (replace username with the actual user):

username ALL=(ALL:ALL) ALL

This means the user can run any command using sudo and will be asked for their password.

Allow User to Run sudo Without Password

If you want the user to run sudo commands without typing a password, use:

username ALL=(ALL:ALL) NOPASSWD:ALL

Allow User to Run Only Specific Commands

To let a user use sudo for just certain commands, list the full paths. For example, to allow mkdir and rmdir without password:

username ALL=(ALL:ALL) NOPASSWD: /bin/mkdir, /bin/rmdir

Or, to require a password for specific commands like apt and systemctl:

username ALL=(ALL:ALL) /usr/bin/apt, /usr/bin/systemctl

Use the /etc/sudoers.d Folder for User Rules

Instead of changing the main sudoers file, you can add a file just for the user inside /etc/sudoers.d. This keeps things organized.

To create a file for a user, run:

sudo visudo -f /etc/sudoers.d/username

Then add your rules inside, for example:

username ALL=(ALL:ALL) NOPASSWD:ALL

Tip: The file name should not contain dots (.) or end with a tilde (~), or sudo will ignore it.

See What sudo Permissions a User Has

To check what commands a user can run with sudo, run:

sudo -l -U username

This shows a list of allowed and forbidden commands for that user.

Summary

• Easy method: Add users to the sudo group to give full sudo access.
• Control access: Edit the sudoers file or add files in /etc/sudoers.d for custom permissions.
• Always use visudo: It prevents mistakes that could lock you out.
• Be careful with passwordless sudo: It can make your system less safe.
• Check sudo permissions regularly: Use sudo -l -U username to verify.

Following these simple steps will help you manage who can do what on your Ubuntu system safely and easily.

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