This site does a masterful job of explaining regular expressions in ruby, java, & perl: http://www.regular-expressions.info The ruby page is a good starting point: http://www.regular-expressions.info/ruby.html And there is a printed book. I plan to have a copy on my bookshelf: http://www.regular-expressions.info/print.html -- Eric Armstrong TreeLight Health, Citizens' Advisory http://www.citizensAdvisory.org -- politics & economics http://www.treelight.com/health -- nutrition & fitness http://www.artima.com -- software design & development