Here are the basics of users and groups! And now, here's containerization and complicated awk commands! I get that it's Chapter 9 in a book, so there is missi

Here are the basics of users and groups! And now, here's containerization and complicated awk commands! I get that it's Chapter 9 in a book, so there is missing context. But I'm also wondering why users and groups seem to be getting intro'd in Chapter 9. And why the author thinks that a person who is learning about users and groups is in any position to consider containers.