Linux add user with sudo

How To Add User To Sudoers & Add User To Sudo Group on Ubuntu

The sudo command is the preferred means to handle elevated permissions. In supported versions of Ubuntu, using the sudo command will grant elevated permissions for 15 minutes.

Standard user accounts are restricted from performing sensitive tasks, such as viewing the contents of the /root directory. This prevents the accidental use of commands with massive consequences. It also makes it more difficult for intruders to compromise a system. However, sometimes you need to run an administrative command. Sudo – or Super User Do – grants you privileges to run sensitive tasks.

This simple tutorial will show you how to add a new user on Ubuntu and provide sudo access.

• A system running a supported version of Ubuntu
• Access to a root user account or another account with sudo privileges
• Access to a terminal window/command line (Ctrl–Alt–T)

Note: Linux Sudo Command tutorials also available for CentOS and Debian.

Steps to Add Sudo User on Ubuntu

Step 1: Create New User

1. Log into the system with a root user or an account with sudo privileges.

2. Open a terminal window and add a new user with the command:

The adduser command creates a new user, plus a group and home directory for that user.

You may get an error message that you have insufficient privileges. (This typically only happens for non-root users.) Get around it by entering:

3. You can replace newuser with any username you wish. The system will add the new user; then prompt you to enter a password. Enter a great secure password, then retype it to confirm.

4. The system will prompt you to enter additional information about the user. This includes a name, phone numbers, etc. – these fields are optional, and can be skipped by pressing Enter.

Step 2: Add User to Sudo Group

Most Linux systems, including Ubuntu, have a user group for sudo users. To grant the new user elevated privileges, add them to the sudo group.

In a terminal, enter the command:

Replace newuser with the username that you entered in Step 1.

Again, if you get an error, run the command with sudo as follows:

sudo usermod -aG sudo newuser

The -aG option tells the system to append the user to the specified group. (The -a option is only used with G .)

Note: Usermod command is a useful tool for user management. To learn more about its options, refer to our guide How To Use The Usermod Command In Linux.

Step 3: Verify User Belongs to Sudo Group

Enter the following to view the groups a user belongs to:

The system will respond by listing the username and all groups it belongs to, for example: newuser : newuser sudo

Step 4: Verify Sudo Access

Replace newuser with the username you entered in Step 1. Enter your password when prompted. You can run commands as normal, just by typing them.

However, some commands or locations require elevated privileges. If you try to list the contents of the /root directory, you’ll get an access denied error: ls /root

The command can be executed with:

The system will prompt for your password. Use the same password you set in Step 1. You should now see the contents of the /root directory.

Now you know how to add and create a user with sudo privileges on Ubuntu.

Before sudo, users would log in to their systems with full permissions over the entire system with the su command. This was risky as users could be exploited by tricking them into entering malicious commands. These vulnerabilities were solved by limiting account privileges. However, administrators still had to log out of their account and into an admin account to perform routine tasks.

The sudo command in Ubuntu strikes a balance – protecting user accounts from malicious or inadvertent damage while allowing a privileged user to run administrative tasks. To learn more about the difference between these commands, check out Sudo vs. Su.

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How to Add and Delete Users on Ubuntu 20.04

Adding and removing users on a Linux system is one of the most important system administration tasks to familiarize yourself with. When you create a new system, you are often only given access to the root account by default.

While running as the root user gives you complete control over a system and its users, it is also dangerous and possibly destructive. For common system administration tasks, it’s a better idea to add an unprivileged user and carry out those tasks without root privileges. You can also create additional unprivileged accounts for any other users you may have on your system. Each user on a system should have their own separate account.

For tasks that require administrator privileges, there is a tool installed on Ubuntu systems called sudo . Briefly, sudo allows you to run a command as another user, including users with administrative privileges. In this guide, you’ll learn how to create user accounts, assign sudo privileges, and delete users.

Prerequisites

To complete this tutorial, you will need access to a server running Ubuntu 20.04. Ensure that you have root access to the server and firewall enabled. To set this up, follow our Initial Server Setup Guide for Ubuntu 20.04.

Adding a User

If you are signed in as the root user, you can create a new user at any time by running the following:

If you are signed in as a non-root user who has been given sudo privileges, you can add a new user with the following command:

Either way, you will be required to respond to a series of questions:

• Assign and confirm a password for the new user.
• Enter any additional information about the new user. This is optional and can be skipped by pressing ENTER if you don’t wish to utilize these fields.
• Finally, you’ll be asked to confirm that the information you provided was correct. Press Y to continue.

Your new user is now ready for use and can be logged into with the password that you entered.

If you need your new user to have administrative privileges, continue on to the next section.

Granting a User Sudo Privileges

If your new user should have the ability to execute commands with root (administrative) privileges, you will need to give the new user access to sudo . Let’s examine two approaches to this task: first, adding the user to a pre-defined sudo user group, and second, specifying privileges on a per-user basis in sudo ’s configuration.

Adding the New User to the Sudo Group

By default, sudo on Ubuntu 20.04 systems is configured to extend full privileges to any user in the sudo group.

You can view what groups your new user is in with the groups command:

By default, a new user is only in their own group because adduser creates this in addition to the user profile. A user and its own group share the same name. In order to add the user to a new group, you can use the usermod command:

The -aG option tells usermod to add the user to the listed groups.

Please note that the usermod command itself requires sudo privileges. This means that you can only add users to the sudo group if you’re signed in as the root user or as another user that has already been added as a member of the sudo group. In the latter case, you will have to precede this command with sudo , as in this example:

Specifying Explicit User Privileges in /etc/sudoers

As an alternative to putting your user in the sudo group, you can use the visudo command, which opens a configuration file called /etc/sudoers in the system’s default editor, and explicitly specify privileges on a per-user basis.

Using visudo is the only recommended way to make changes to /etc/sudoers because it locks the file against multiple simultaneous edits and performs a validation check on its contents before overwriting the file. This helps to prevent a situation where you misconfigure sudo and cannot fix the problem because you have lost sudo privileges.

If you are currently signed in as root, run the following:

If you are signed in as a non-root user with sudo privileges, run the same command with the sudo prefix:

Traditionally, visudo opened /etc/sudoers in the vi editor, which can be confusing for inexperienced users. By default on new Ubuntu installations, visudo will use the nano text editor, which provides a more convenient and accessible text editing experience. Use the arrow keys to move the cursor, and search for the line that reads like the following:

Below this line, add the following highlighted line. Be sure to change newuser to the name of the user profile that you would like to grant sudo privileges:

root ALL=(ALL:ALL) ALL newuser ALL=(ALL:ALL) ALL 

Add a new line like this for each user that should be given full sudo privileges. When you’re finished, save and close the file by pressing CTRL + X , followed by Y , and then ENTER to confirm.

Testing Your User’s Sudo Privileges

Now your new user is able to execute commands with administrative privileges.

When signed in as the new user, you can execute commands as your regular user by typing commands as normal:

You can execute the same command with administrative privileges by typing sudo ahead of the command:

When doing this, you will be prompted to enter the password of the regular user account you are signed in as.

Deleting a User

In the event that you no longer need a user, it’s best to delete the old account.

You can delete the user itself, without deleting any of their files, by running the following command as root:

If you are signed in as another non-root user with sudo privileges, you would use the following:

If, instead, you want to delete the user’s home directory when the user is deleted, you can issue the following command as root:

If you’re running this as a non-root user with sudo privileges, you would run the same command with the sudo prefix:

If you previously configured sudo privileges for the user you deleted, you may want to remove the relevant line again:

Or use the following command if you are a non-root user with sudo privileges:

root ALL=(ALL:ALL) ALL newuser ALL=(ALL:ALL) ALL # DELETE THIS LINE 

This will prevent a new user created with the same name from being accidentally given sudo privileges.

Conclusion

You should now have a fairly good handle on how to add and remove users from your Ubuntu 20.04 system. Effective user management will allow you to separate users and give them only the access that they are required to do their job.

For more information about how to configure sudo , check out our guide on how to edit the sudoers file.

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