Because the theory of pipes should now be relatively simple (as we got most of it out of the way when we talked about input and output redirection), we'll present a number of practical examples that really illustrate the power of pipes.

It is good to remember that pipes only work on commands that accept input from stdin; not all do. If you pipe something to a command that totally disregards that input, you'll probably be disappointed with the results.

Since we have now introduced pipes, we'll use them more liberally in the rest of the book. While these examples will present some ways of using pipes, the rest of the book will contain many more!