Unix Power Tools, 3rd Edition

Chapter 8. Directories and Files

Everything but the find Command

A computer isn’t that much different from a house or an office; unless you’re incredibly orderly, you spend a lot of time looking for things that you’ve misplaced. Even if you are incredibly orderly, you still spend some time looking for things you need — you just have a better idea of where to find them. After all, librarians don’t memorize the location of every book in the stacks, but they do know how to find any book, quickly and efficiently, using whatever tools are available. A key to becoming a proficient user of any system, then, is knowing how to find things.

This chapter is about how to find things. We’re excluding the find (Section 9.1) utility itself because it’s complicated and deserves a chapter of its own. We’ll concentrate on simpler ways to find files, beginning with some different ways to use ls.

Well, okay, towards the end of the chapter we’ll touch on a few simple uses of find, but to really get into find, take a peek at Chapter 9.

— ML

The Three Unix File Times

When you’re talking to experienced Unix users, you often hear the terms " change time” and “modification time” thrown around casually. To most people (and most dictionaries), “change” and “modification” are the same thing. What’s the difference here?

The difference between a change and a modification is the difference between altering the label on a package and altering its contents. If someone says chmod a-w myfile, that is a change; if someone ...