Found a great post over at good coders code, great reuse. This one deals with performing operations on sets using only unix (bash) command line operations on files of text.

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Set Membership.Test if an element belongs to a set.

*Set Equality.Test if two sets contain the same elements.

*Set Cardinality.Return the number of elements in the set.

*Subset Test.Test if a given set is a subset of another set.

*Set Union.Find union of two sets.

*Set Intersection.Find intersection of two sets.

*Set Complement.Given two sets A and B, find all elements in A that are not in B.

*Set Symmetric Difference.Find symmetric difference of two sets.

*Power Set.Generate all subsets of a set.

*Set Cartesian Product.Find A x B.

*Disjoint Set Test.Test if two sets are disjoint.

*Empty Set Test.Test if a given set is empty.

*Minimum.Find the smallest element of a set.

*Maximum.Find the largest element of a set.

It deals with such commands as sed, awk, tr, sort, comm, grep and wc. This is a good post for anyone dealing with data via command line linux.