The following resources might be interesting if you'd like to go deeper into the subjects of this chapter:
- Fundamentals of Linux by Oliver Pelz, Packt: https://www.packtpub.com/networking-and-servers/fundamentals-linux
- File attributes: https://linoxide.com/how-tos/howto-show-file-attributes-in-linux/
- Special file permissions: https://thegeeksalive.com/linux-special-permissions/
- Access Control Lists: https://www.tecmint.com/secure-files-using-acls-in-linux/