How to debug Lucene indexes

Lucene search is a god’s gift to man,.. it is fast and easy to use with sitecore ,.. but from time to time you have to debug it,..
So how do you read the generated indexes ,.. well ,.. I found this wonderful free toolbox made http://www.getopt.org/luke/ made by
Andrzej Bialecki,.. it is java ,.. and it is wonderful ,..
luke