Managing accounts is one of the first administrative skills I learned when working with Linux servers. Whether I am preparing a development environment, granting a colleague access, or separating permissions between teams, users and groups help me control who can access files, applications, and system resources.
In this guide, I will explain How to Create Users and Groups in Linux using practical terminal commands. I will also cover primary and supplementary groups, password creation, home directories, account verification, administrative privileges, shared folders, deletion, and common errors.
What Are Linux Users and Groups?
A Linux user is an account that can own files, run programs, and access system resources. Each user receives a unique numerical user ID, commonly called a UID.
A group is a collection of users who share certain permissions. Groups make administration easier because I can grant access to several users at once instead of changing permissions for every account individually.
Linux normally stores account information in these files:
- /etc/passwd contains basic user details.
- /etc/group contains group names and memberships.
- /etc/gshadow stores protected group information.
These files should not normally be edited manually. Linux provides commands that update them safely.
Primary and Supplementary Groups
Every Linux user has one primary group. Files created by that user are usually assigned to this group automatically.
A user can also belong to several supplementary groups. These additional memberships provide access to shared folders, administrative commands, applications, hardware, or services.
The -g option assigns a primary group, while -G assigns supplementary groups.
Check Existing Users and Groups First
Before creating an account, I check whether the username or group already exists.
getent passwd alex
getent group developers
If the commands return no output, the names are probably available.
I can also inspect all local account and group records with:
cat /etc/passwd
cat /etc/group
Using getent is generally safer because it can display accounts from local files and connected identity services.
Create a New Group in Linux
To create a group named developers, run:
sudo groupadd developers
Verify that the group was created:
getent group developers
The output should display the group name and its assigned group ID.
Create a Group With a Specific GID
Linux normally assigns the next available group ID automatically. When matching permissions across several systems, I may need a specific GID.
sudo groupadd -g 2500 developers
The selected number must not already belong to another group. Check it before proceeding:
getent group 2500
Create a New Linux User
The useradd command creates a user account. I include -m so Linux also creates a home directory.
sudo useradd -m alex
Set a secure password:
sudo passwd alex
The terminal will ask for the new password twice. Password characters will not appear while typing, which is normal.
Choose a Login Shell
To create the account with Bash as its login shell, run:
sudo useradd -m -s /bin/bash alex
The -s option defines the program that starts when the user opens a terminal session.
For a service account that should not allow interactive login, use:
sudo useradd -r -s /usr/sbin/nologin appservice
The -r option creates a system account.
Create a User With a Primary Group
To create a user and assign developers as the primary group, run:
sudo useradd -m -s /bin/bash -g developers alex
sudo passwd alex
The group must exist before running this command.
Verify the result:
id alex
The output displays the user’s UID, primary GID, and supplementary memberships.
Add an Existing User to a Group
To add an existing user to a supplementary group, use:
sudo usermod -aG developers alex
The -a option means append, while -G specifies supplementary groups.
Never omit -a unless you intentionally want to replace the user’s existing supplementary memberships. Running usermod -G alone can remove access to other groups.
Verify the updated membership:
groups alex
You can also use:
id alex
Add a User to Multiple Groups
Separate several group names with commas and no spaces:
sudo usermod -aG developers,docker,projectteam alex
Each listed group must already exist.
Activate the New Membership
Group changes may not affect an existing login session immediately. The user should log out and sign in again.
For temporary access in the current terminal, run:
newgrp developers
A new shell will start with the selected group active.
Create a User on Ubuntu and Debian
Ubuntu and Debian provide the friendlier adduser utility:
sudo adduser alex
This interactive command creates the home directory, selects common defaults, asks for a password, and optionally collects account details.
Create a group with:
sudo addgroup developers
Add the user to it:
sudo adduser alex developers
Both adduser and useradd can create accounts, but adduser guides beginners through the process while useradd provides direct control through options.
Grant Administrative Privileges
Administrative access should only be given when necessary.
On Ubuntu and Debian, add the user to the sudo group:
sudo usermod -aG sudo alex
On Fedora, Rocky Linux, AlmaLinux, and similar systems, use the wheel group:
sudo usermod -aG wheel alex
After signing in again, test administrative access:
sudo whoami
A successful command should return root.
Use a Group for a Shared Directory
Groups become especially useful when several people need to work in the same directory.
Create the shared folder:
sudo mkdir -p /srv/project
Assign its group ownership:
sudo chown :developers /srv/project
Set collaborative permissions:
sudo chmod 2775 /srv/project
The leading 2 enables the setgid permission. New files and subdirectories created inside the folder inherit the developers group, making collaboration more consistent.
Change a User’s Primary Group
To change the primary group of an existing account, run:
sudo usermod -g developers alex
Confirm the change:
id alex
Changing the primary group does not automatically update ownership of older files. Review and adjust existing files when required.
Delete Users and Groups Safely
Delete a user while keeping the home directory:
sudo userdel alex
Delete the account and its home directory:
sudo userdel -r alex
Before using -r, back up any important files.
Delete an unused group with:
sudo groupdel developers
Linux will refuse to remove a group if it is still configured as a user’s primary group.
Troubleshoot Common Problems
The User Already Exists
If Linux reports that the user already exists, verify the account:
getent passwd alex
Choose another username or modify the existing account.
The Group Does Not Exist
Create the group before assigning it:
sudo groupadd developers
Then repeat the useradd or usermod command.
Permission Is Denied
User and group management requires root privileges. Add sudo before the command or sign in through an authorized administrative account.
Group Access Is Still Not Working
Ask the user to log out and sign in again. Also verify the folder’s ownership and permissions:
ls -ld /srv/project
id alex
Group membership alone does not grant access when directory permissions block the group.
Frequently Asked Questions
1. How to Create Users and Groups in Linux at the Same Time?
Create the group first with groupadd, then create the user with useradd -m -g groupname username, and finally set the password using passwd.
2. How Do I See Every Group a User Belongs To?
Run groups username for a simple list or id username for UID, GID, and complete membership details.
3. What Is the Difference Between -g and -G?
The lowercase -g sets one primary group, while uppercase -G assigns one or more supplementary groups.
4. Does useradd Automatically Create a Home Directory?
Not on every system. Use the -m option to ensure the account receives a home directory.
Wrapping Up Your Linux Account Setup
When I manage Linux accounts, I follow a repeatable process: check existing records, create the required group, create the user with a home directory, assign the correct memberships, set a secure password, and verify every change.
Learning How to Create Users and Groups in Linux also makes file permissions, shared directories, application access, and server security easier to understand. By using groupadd, useradd, usermod, passwd, id, and getent carefully, I can maintain organized accounts without manually editing sensitive system files.