Possible Duplicate:
Linux tools to treat files as sets and perform set operations on them
I have two data sets, A and B. The format for each data set is one number per line. For instance,
12345
23456
67891
2345900
12345
Some of the data in A are not included in data set B. How to list all of these data in A, and how to list all of those data shared by A and B. How can I do that using Linux/UNIX commands?