The problems presented in this chapter aren’t the kind of real-world problems that your boss or your customers ask you to solve. Rather, they’re technical problems you’ll encounter while creating and editing regular expressions to solve real-world problems. The first recipe, for example, explains how to match literal text with a regular expression, and how to deal with characters that have special meanings in regular expressions. This isn’t a goal on its own, because you don’t need a regex when all you want to do is to search for literal text. But when creating a regular expression, you’ll likely need it to match certain text literally, and you’ll need to know which characters to escape. Recipe 2.1 tells you how.

The recipes start out with very basic regular expression techniques. If you’ve used regular expressions before, you can probably skim or even skip them. The recipes further along in this chapter will surely teach you something new, unless you have already read Mastering Regular Expressions by Jeffrey E.F. Friedl (O’Reilly) cover to cover.

We devised the recipes in this chapter in such a way that each explains one aspect of the regular expression syntax. Together, they form a comprehensive tutorial to regular expressions. Read it from start to finish to get a firm grasp of regular expressions. Or dive right in to the real-world regular expressions in Chapters 4 through 9, and follow the references back to this chapter whenever those chapters use some syntax you’re not familiar with.

This tutorial chapter deals with regular expressions only and completely ignores any programming considerations. The next chapter is the one with all the code listings. You can peek ahead to Programming Languages and Regex Flavors in Chapter 3 to find out which regular expression flavor your programming language uses. The flavors themselves, which this chapter talks about, were introduced in Regex Flavors Covered by This Book.