User login

Perl hints

strict warning: Only variables should be passed by reference in /usr/share/drupal6/modules/book/book.module on line 559.

List of hints:

install CPAN (module archive) module
install module
install module from CPAN shell
install module with CPAN, answer yes/default
install module with CPAN, force
install Net::SSH::Perl on cygwin
use threads
operator continue

operator break
regexp conditional
supress "uninitialized value" warning
multi-line comments
scalar to array/hash
typeof for refrence types