We have stressed so far the importance of giving a structure to our scripts, to make them flexible, and to have them react to some conditions and situations so that they will help us automate some routine tasks making decisions and performing actions on our behalf. What we saw in the previous chapters enables us to assign variables, change their values in different ways, and also to preserve them; but from the examples shown, it is clear that we need some more and this is what this new chapter is all about. We will see how to test, make comparisons, and get to react accordingly to the results, and we will give our first structure to a script having to make a decision if something happens.