IN THIS CHAPTER
Understanding files and directories
Understanding disks and disk partitions
Understanding logical volumes
Understanding Linux filesystems
Introducing users and groups
Understanding privileged operations on Ubuntu systems
This chapter explains basic Linux system concepts, focusing on how data is stored and organized on all Linux systems and how the Linux operating system controls access to that data and to privileged operations. Aside from specific sections on how Ubuntu deals with and grants high-level permissions, the information in this chapter applies to any Linux system and to most other UNIX-like systems.
In this chapter, I err on the side of caution. As impossible as it now sounds, I had never used a computer before deciding to study computer science at university. (I can be excused for this to some extent because this was a zillion years ago, just as personal computers were starting to become popular and long before DOS, Microsoft Windows, Apple Macintosh, and so on.) At any rate, I remember sitting in my first computer science class while the professor said things such as, "Once you write your program, save it to a file," and thinking, "What the heck is he talking about?"
This chapter therefore contains some sections, such as "Working with Files and Directories" that you might find insulting in their simplicity and exploration of basic concepts that "everybody knows," which is fine with me. Everybody who knows that stuff can ...