How to Add a User to Sudoers in Ubuntu

1Add User to the sudo Group (Easiest Way)

Adding a user to the ‘sudo’ group in Ubuntu grants them administrator rights, allowing them to run commands that affect the whole system. This method permits users to install software or manage files, and it’s suitable for everyday tasks requiring 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’ll want to control precisely which commands a user can execute using 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:

Giving a user full sudo access in Ubuntu means they can run any command with administrator rights. Sudo access is granted by editing the special ‘sudoers’ file to add a specific rule for that user. Once added, the user can use the ‘sudo’ command to perform powerful system actions.

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, a security measure.

Allow User to Run sudo Without Password

You can allow a user to run sudo commands without typing their password in Ubuntu by editing the sudoers file, located at /etc/sudoers. Adding a specific rule tells the Ubuntu system not to ask for a password each time a sudo command runs. This passwordless sudo change makes running commands faster but reduces security, so use this setting with caution.

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

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

The `/etc/sudoers.d` folder in Ubuntu manages user permissions for running commands as administrator. Instead of editing the main `/etc/sudoers` file, create a new, separate file within `/etc/sudoers.d` for each user’s specific rules. This organization method groups permissions, making it easier to see exactly what each user can do.

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. For custom control over sudo permissions, edit the main sudoers file or use the cleaner /etc/sudoers.d folder. Always use the ‘visudo’ command, which checks for errors, when editing sudoers files. Be very careful when allowing passwordless sudo, as it lowers security.