That doc describes all of the caveats for writing ePN plugins, the big ones being no named subs, no BEGIN/END blocks and close your files (as exit is never called). The output generated should be pretty short and readable even with a few chars fubarded on a alpha page. and the exit status codes (even though the table in the doco says the numerics) should be pulled out of util.pm (%ERRORS).

-Waswas