Hm. An interesting list. Off the top of my head:
- What strict and warnings are for, and why they should almost always be used.
- The differences between scalar, list, and void context.
- How to use the CPAN effectively.
- Test-driven development (e.g. with Test::Harness and Test::More).
- How (Not) To Ask A Question
- Correct usage of my, our, local.
- Proper reference construction and use.
- Basic understanding of Perl RegEx.
- How to write a module (e.g. have read perlmodlib and perlmodstyle).
- How to accommodate multiple OSes (e.g. using File::Spec).