Abigail is right. I use __DATA__ if I can get away with it and it won't make my life difficult later. Most of the times I can't since the scripts I write tend to be installed and reinstalled on different machines requiring different configurations, and I don't want to edit the script each time I install. You may even be able to use both methods at the same time in some cases (i.e. use a config file if it exists, or use __DATA__ if it doesn't).