Could just be a typo in your submission, but if you're
printing "Hello World/n" instead of "Hello World\n" (note
the direction of the \), that could cause some problems.
Depending on how Mandrake builds things, this could cause
your next prompt to have "Hello World/n" prepended to it
(e.g., "Hello World/nesper@monastery$") or prevent anything
from printing.