Managing User and Group Creation with Useradd Command

Managing user and group creation in Linux systems often requires precise control over user and group associations. The useradd command is a fundamental tool for adding users to the system, and the -N or --no-user-group option provides a specific functionality within this command.

When you use useradd -N, it adds a user without creating a group for that user. This can be useful in scenarios where you want to manage user groups separately or when user-specific groups are not needed.

Here are some examples demonstrating the usage of useradd -N:

Example 1: Create a user without a corresponding group
sudo useradd -N john
This command creates a user named ‘john’ without creating a group named ‘john’.

Example 2: Add a user and verify the group creation
sudo useradd jane
sudo groupadd janegroup
sudo usermod -aG janegroup jane
sudo useradd -N george
This sequence adds a user ‘jane’ to a group ‘janegroup’ and then adds a user ‘george’ without creating a group for ‘george’.

Example 3: Ensure a user without a group is created
sudo useradd -N -s /bin/bash -m michael
This command creates a user ‘michael’ without assigning any group.

To verify if the useradd -N command executed successfully:

1. Check the output for any errors or confirmations provided by the command itself.
2. Use the grep command to check if the user exists in the system’s password file:
   grep 'username' /etc/passwd
3. If the user exists and does not have a corresponding group, the command was successful.