Unhide.rb finds hidden processes on your system. It looks for active processes in many different ways. Processes found by some means but not others are considered to be "hidden", and are reported to the user. Unhide.rb is a Ruby rewrite of the original Unhide, which was written in C. Unhide.rb performs the same checks as the original, but is 10 times faster in only half as much code, and has better diagnostics when hidden processes are found.
Chef is a systems integration framework, built to bring the benefits of configuration management to your entire infrastructure. With Chef, you can manage your servers by writing code, not by running commands (via Cookbooks), integrate tightly with your applications, databases, LDAP directories, and more (via Libraries), and easily configure applications that require knowledge about your entire infrastructure ("What systems are running my application?" "What is the current master database server?").