The first of the Finder scripts, About Finder Scripts, just puts up the dialog shown in Figure 3.3.
Figure 3.3 Scripts can warn you of what they're going to do.
You should be careful running these scripts because they do just what the dialog warns you; they rename selected files in the frontmost window or on the desktop. They're a wonderful way to make wholesale changes in filenames, such as replacing text or shortening them. But after you click OK, they will act on the selected files all together. If you have accidentally left your hard disk icon selected, you could wind up renaming a very large number of files all over your hard disk.
So if you want to experiment with Finder Scripts, create a test file and a test folder, make sure they're selected, and then explore the scripts.