'ipkg search xxx' always returns no answer

On a Synology NAS (uses a 'home grown' *nix variant (possibly based on Debian?)) I have installed ipkg package manager. When I try a command like ipkg search shred or ipkg search *shred* it returns only the single line: Successfully terminated without any package name. I specifically used shred in my example as I know that shred exists for my platform and is part of the coreutils package (and so should return that answer.) What is going wrong? Is this a bug, an error in my syntax or possibly something else? Edit - I found the answer - filename needed to be enclosed in single quotes like ipkg search '*shred*' This returns the correct answer - coretutils. I also found that Pavel is correct, it only returns info on *installed* packages, which is not what I needed. How would I go about finding what pkg to install if I need a given program/util that is part of a larger collection but don't know what package contains it? (is that permitted or should I start another question?)