When installing Ubuntu, or any Linux distro, a root user will be created. However, there are many times when you need to create additional users with root
or sudo
privileges. Thankfully, Linux makes this fairly simple to do using the adduser
and usermod
commands for creating new users and adding them to specific group assignments.
Let’s take a look new users to Linux machines and granting them sudo
permissions!
Create a User in Linux using the adduser
Command
The adduser
command is used to create a new user in Linux. The simplest usage of this command is to call it by passing in the username of the new user you would like to create. Calling this command must be done as root
, you can do this with the help of sudo
.
sudo adduser <username>
Tip: You can run the shell as
root
by using thesudo -s
command. This will run the shell with elevated root privileges until you type theexit
command. This can help if you are running multiple commands that will need root privileges so you don’t need to prefix every command withsudo
.
When calling the adduser
command, you will be prompted for additional information for the user account you are creating. The required thing to enter will be the Password for the user, but it will also prompt for additional user metadata that is optional.

adduser
command to create a new user on LinuxGive Linux User Root / Sudo Permissions
Now that we have a new user created on our Linux machine, this user will also need to be assigned root
permissions so they are made an administrator on this machine. This can be done by on Ubuntu by adding the user to the sudo
group. With default configuration of Ubuntu, being a member of the sudo
group will grant the user sudo
privileges.
The usermod
command can be used to assign the desired user to the sudo
group within Ubuntu Linux. Keep in mind this command must be run with sudo privileges, so you’ll need to use sudo
to run it.
sudo usermod -aG sudo <username>
Notice the -aG
flag is used with the usermod
command. This flag will append this user to the specified group. Then the command must be given the <username>
of the User you will be modifying. In this case we are specifying the sudo
group to append the specified user to.

sudo
groupCheck if Logged in User has sudo
Privileges
Once a user have been added to the sudo
group on Ubuntu they will have sudo
privileges. If you are logged into an Ubuntu machine and don’t know if you have sudo
privileges, then you can use the sudo
command with the -l
flag to check.
sudo -l
This command will list out all sudo
privileges you have. If you do not have any, then it will return a message that reads “Sorry, user <username> may not run sudo on <machine-name>.”

sudo
privileges on LinuxLookup All Users in sudo
Group
In Linux, the /etc/group
file is used to determine the groups that users belong to. The contents of this file will list out all group assignments on a particular Linux machine. You can look within this file to check if a given user is a member of a group; like checking if the user is in the sudo
group.
An easy way to check if a user is in the sudo
group, is to lookup what users are members of the sudo
group as listed within the /etc/group
file using the cat
command to output to the console, and the grep
command to search within the file before outputing to the console. You can do this with the following command:
sudo cat /etc/group | grep sudo

sudo
groupAnother related query to this, is to use grep
to search for the users name instead of sudo
. This would enable you to lookup all the groups the specified user is a member of using this same command.
cat /etc/group | grep chris

Wrap Up
Once this command is run successfully, the specified user will now be a part of the sudo
group on your Ubuntu machine. They will now essentially be an administrator with root
permissions on the machine. Use the adduser
and usermod
commands, you can create new admin accounts for additional users and grant them sudo
privileges on your Ubuntu Linux machines. Additionally, checking the /etc/group
file will enable you to lookup what groups different users are already assigned to.
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