This is Perl module Iterator::GroupedRange. INSTALLATION Iterator::GroupedRange installation is straightforward. If your CPAN shell is set up, you should just be able to do % cpan Iterator::GroupedRange Download it, unpack it, then build it as per the usual: % perl Makefile.PL % make && make test Then install it: % make install DOCUMENTATION Iterator::GroupedRange documentation is available as in POD. So you can do: % perldoc Iterator::GroupedRange to read the documentation online with your favorite pager. Toru Yamaguchi