Managing users on a Raspberry Pi is an essential task for maintaining security and ensuring proper access control. Whether you're setting up a Raspberry Pi for personal use, as a server, or for a project, understanding user management is crucial. This guide will walk you through the process of creating, modifying, and deleting users, as well as managing their permissions using the command line.

Examples:

1. Creating a New User:

   To create a new user on your Raspberry Pi, you can use the adduser command. This command not only creates a user but also sets up a home directory and prompts you to set a password.

   sudo adduser newusername

   Follow the prompts to set the password and fill in any additional information if necessary.

2. Modifying User Permissions:

   To modify user permissions, you can add the user to specific groups. For example, to grant a user sudo privileges, you can add them to the sudo group:

   sudo usermod -aG sudo newusername

   This command appends the user to the sudo group, allowing them to execute commands as the superuser.

3. Deleting a User:

   If you need to remove a user and their home directory, use the deluser command with the --remove-home option:

   sudo deluser --remove-home newusername

   This command deletes the user and their home directory, freeing up space and ensuring that no residual files are left behind.

4. Listing All Users:

   To view all users on your Raspberry Pi, you can check the /etc/passwd file:

   cat /etc/passwd

   This file contains all user account information. Each line represents a user, with fields separated by colons.

5. Changing a User's Password:

   To change a user's password, use the passwd command:

   sudo passwd newusername

   You'll be prompted to enter a new password for the user.

6. Switching Between Users:

   To switch between users, use the su command followed by the username:

   su - newusername

   This command switches the current session to the specified user.