How to configure user permissions and access control in Ubuntu

User permissions and access control in Ubuntu can be configured by following these steps:

1. create a new user
2. Create a new user account using the command “sudo adduser newuser”.
3. modify user
4. Add the user named “username” to the group named “groupname” using superuser privileges.
5. change the permission of a file or directory
6. Give the file named “filename” read, write, and execute permissions for the owner, and read and execute permissions for group members and others.
7. change owner
8. Change the owner and group of the file “filename” to “newowner” and “newgroup” using super user privileges.
9. assign file permissions
10. Grant the user “newuser” read, write, and execute permissions on the file “filename” using setfacl command.
11. execute as superuser
12. Add the user to the sudo group.

By following the steps above, you can effectively configure user permissions and access controls to protect the security and availability of the system.