How to Add a User to Sudoers in Ubuntu

Quick Reference

1Add User to the sudo Group (Easiest Way)

Adding an Ubuntu user to the sudoers list grants administrator privileges. This action adds the user to the 'sudo' group. Membership in the 'sudo' group allows users to run computer commands with administrator power. This administrator power enables users to make system-wide changes.

Step 1: Open the terminal.

Step 2: Run this command, replacing 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 take effect. Alternatively, they can start a new login shell:

su - username

Check the User’s Groups

To confirm the user is in the sudo group, run this command:

groups username

You should see the user’s name 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!

2Give 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.

Open sudoers File Safely

In the terminal, run:

sudo visudo

This command opens the sudoers file in the default editor.

If you prefer the nano editor (which many users find more intuitive), run:

sudo EDITOR=nano visudo

Give Full sudo Access to a User

At the bottom of the file, add this line, replacing username with the actual user:

The added user gains the ability to run any command as the superuser using the `sudo` command. When the user executes a command with `sudo`, the system will prompt for the added user's password for verification, which is a security measure.

Allow User to Run sudo Without Password

Granting a user passwordless sudo access in Ubuntu requires changing the sudoers file. Administrators must add the `NOPASSWD: ALL` rule to the user's entry in the sudoers file. This change lets the user run any command with administrator rights without needing a password, speeding up repeated jobs.

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

Managing sudo rules for individual users in Ubuntu is cleaner and safer by using the /etc/sudoers.d folder, which lets you create separate files for each user’s permissions.

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 this:

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.

To manage sudo permissions in Ubuntu, you can add users to the ‘sudo’ group for full access, or use the /etc/sudoers.d folder for custom rules on specific commands.