This is an online course about regular expressions. These are cryptic little things that do a lot of magic in most modern programming languages. The first time you encounter regular expressions you might wonder how someone could write such cryptic hieroglyphs. The aim of this course is that you learn by doing simple text matching. Unlike most webpages about regular expressions I will guide you step by step and not overwhelm you with all the possibilities. After you get familiar with the examples we will step on and make some more complicated things.