How can I restrict the permissions of a specific user in Ubuntu?

To ban a user’s access, you can follow these steps:

1. Open the terminal window.
2. Login using the root user or a user with sudo privileges.
3. Use the following command to add a user to the sudo group, this will allow the user to have administrator privileges:
4. Add the user to the sudo group.
5. The username corresponds to the username of the user who is to be banned.
6. If a user has been added to the sudo group, you can use the following command to remove them from the sudo group:
7. Remove the user named “username” using sudo.
8. The username is the username of the user whose access needs to be restricted.
9. To fully restrict a user’s permissions, you can remove them from the sudo group and all other groups using the following command:
10. Remove the user and its home directory.
11. The username is the username of the user whose banning privileges are to be revoked.
12. After banning user privileges, restart the system to make the changes take effect.
13. Restart the system as a superuser.

Please be advised that restricting user access may have an impact on system functionality and other users, so please proceed with caution.