You should not be typing the "%" symbol at the start of the line. As Bear suggests, you will need to learn a bit about whatever unix shell you are using (typically Bash under OSX). Perhaps look for a tutorial on Bash on the internet to start with.
Originally posted by Simon Dean:
2) How do I make sure Terminal is pointing at the right folder? At the moment, when I run "%javac myprogram.java", I get "no such job".