HashSet, TreeSet equivalent in Linux

I was thinking of implementing a command line version of Java HashSet, LinkedHashSet and TreeSet when I remembered sort and uniq.

Just use uniq as you would a HashSet/LinkedHashSet. And sort a you would a TreeSet. And use GnuWin32 on Windows.

Goodbye new open-source project. Perhaps a command line version of Map, SortedMap, and BidiMap?

Update (April 10, 2013): There is still hope for Set.retainAll() (union), Set.removeAll() (intersection)..