How to Fix Username is not in the sudoers file. This incident will be reported in Ubuntu?

Introduction

If you're a user of Ubuntu, there's a chance that at some point, when trying to run a command as the superuser or administrator, you may have encountered an error message that reads: "Username is not in the sudoers file. This incident will be reported."

This message typically appears when you attempt to execute an administrative command using the 'sudo' command and your system does not recognize your username as having sufficient permissions to perform such actions.

This error results from your username being absent in the sudoers file - a system configuration file that specifies which users and groups are allowed to use the 'sudo' command for administrative purposes. When this happens, attempting any administrative task becomes impossible because you lack sufficient privileges required to execute such commands.

Understanding Sudo and Sudoers File

Defining Sudo and its Functionality

Sudo is a powerful utility command that enables users with non-administrative accounts to perform administrative tasks on a Linux or Unix system. It stands for "SuperUser DO" and allows authorized users to run commands with elevated privileges. When executing a sudo command, the user must enter their own password as authentication before gaining temporary root access.

Sudo is essential for managing system security since it limits who can execute privileged commands. The ability to restrict the use of sudo provides an additional layer of protection against security threats by ensuring only trusted users can perform sensitive operations.

Role of the Sudoers File in Granting Administrative Privileges

The sudoers file is responsible for specifying which users can run specific commands using sudo. The file contains rules that define what level of access a particular user has once they execute a sudo command. It determines whether users are authorized to become root or another user with given privileges, as well as which commands they are permitted to run.

This file also allows administrators to set up custom roles for different groups of users based on their responsibilities, such as database administrators or network engineers. Each entry in the file includes details about what type of commands can be executed by each user, what privileges they have, and from which host machines they can operate.

How Ubuntu Uses the Sudo Command to Manage Administrative Tasks

In Ubuntu, you must have sudo privileges in order to carry out administrative tasks like installing software packages or modifying system settings. By default, Ubuntu comes with one administrative account called 'root,' but it's disabled by default for security reasons.

Instead, Ubuntu utilizes the sudo command via terminal applications such as GNOME Terminal or Bash Terminal. This approach ensures that all administrative actions performed by users are logged appropriately and that the system remains secure.

Sudo and the sudoers file work together to enable authorized non-administrative users to perform necessary system tasks while maintaining security. The sudo command allows users to perform administrative tasks safely by controlling who has access and what they can do, while the sudoers file provides an easy-to-manage method of configuring these privileges.

Diagnosing the Problem

Identify Common Causes of "Username is not in the sudoers file" Error Message

If you come across the error message “Username is not in the sudoers file. This incident will be reported” while trying to execute a command with elevated privileges in Ubuntu, it means that you do not have sufficient permissions to run that command. This can happen due to several reasons, some of which are −

• The user account does not have sudo privileges.

• You are using an incorrect password for the current user account.

• The sudoers file has been accidentally or intentionally modified and no longer recognizes your user account as having sudo privileges.

• The system has encountered a bug or malfunction that prevents you from accessing sudo privileges.

Explain How to Check if a User Has Sudo Privileges or Not Using Terminal Commands

To check whether a user has sudo privileges or not, use the following steps −

• Open a terminal window by pressing Ctrl + Alt + T on your keyboard.

• Type in the following command and press Enter −

sudo -l 

This will prompt you for your password.

Type it in and press Enter.

• If you have administrative privileges, then you should see a list of commands that you are authorized to run with elevated permissions.

• If you don't have administrative privileges, then an error message will inform you that "username is not in the sudoers file". Another way to check if a user has root access is by checking their group membership status.

By default, only users who belong to "sudo" group can execute commands with root permission using "sudo". You can confirm this by running −

groups username 

Replace `username` with actual username of the person whose permission status you want to check.

Knowing how to diagnose the problem for "Username is not in the sudoers file" error message will help you understand why you don't have sufficient privileges to execute a command with elevated permissions. By checking if your user account has sudo privileges, you can determine if you need to add yourself to the sudoers group or modify the sudoers file to grant yourself administrative privileges.

Fixing Username Not in Sudoers File Error

Method 1: Adding User to Sudo Group

Adding a user to the sudo group is the simplest and most common method of granting them administrative privileges. Users who belong to this group can execute commands with elevated permissions using the sudo command. This means that they can perform administrative tasks such as installing software, updating packages, and modifying system settings without logging in as root.

To add a user to the sudo group in Ubuntu, follow these steps −

• Open the terminal by pressing Ctrl+Alt+T or by searching for it in your application menu.

• Type the following command: `sudo adduser username sudo`, replacing "username" with your actual username.

• Enter your password when prompted and press Enter.

• Wait for the command to complete, then exit the terminal.

Now that you have been added to the sudo group, you should be able to use sudo commands on your system without encountering any "Username is not in the sudoers file" error messages.

Method 2: Editing Sudoers File

The other way of granting or revoking administrative privileges for users is by editing the /etc/sudoers file. This involves modifying access control lists (ACLs) that determine which users are allowed to use certain commands with elevated privileges.

However, editing this file should be done with caution since any errors made while editing can cause serious issues like losing access to your system entirely. To edit this file in Ubuntu −

• Open terminal

• Type − `sudo visudo`

• Look for lines starting with `%sudo` or `%admin`.

• Add this line after `%admin ALL=(ALL) ALL`: `your-username-here ALL=(ALL) ALL`.

  Replace "your-username-here" with your actual username.

• Save the file and exit the text editor.

Now, log out of your system and log in again for the changes to take effect. You should now have administrative privileges when using the sudo command.

Conclusion

Encountering the "Username is not in the sudoers file" error message can be frustrating, especially if you need to perform administrative tasks on your system regularly. However, by following either of these two methods mentioned in this article, you can easily regain administrative privileges and continue performing your tasks without any issues.

It is important to note that both methods require proper understanding and caution while executing them. Therefore it is advised that you stick to Method 1 i.e adding user to sudo group if you are not very confident with editing files or making changes through terminal commands.