Set Operations on the Command Line

Performing set operations, such as union, intersection, and difference, is easy in linux using basic command line utilities like sort and comm (for compare).

Here is a cheat sheet for the basic set operations:

Set Operation	Linux Equivalent
A UNION B	sort -mu A B
A INTERSECTION B	sort A B | uniq -d -or- comm -12 A B*
A MINUS B	comm -23 A B*

* Both A and B need already be sorted.

Here is a more in depth article with some comments on performance and some alternative commands.