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