i either use the config module (if i need sections within config) or just use a plain txt file that has a variable then pipe character then value, per line. a short routine reads in the config variables as hash key and value pairs into %config hash, which override any previously defined (hardcoded) defaults. keeps the config neatly separate from any other variables, and you can clearly see where you do make use of config vars. i can't take the credit for this, as that's the way a large piece of software i worked on did.