F (2006)
It is often said that K can beat the speed of C for some tasks.The name of this site is "nsl" for No Stinking Loops.Here is an array programming challenge for the K programmers reading this thread.There are two large files A and B.   File A
   AAAbjhOJxxxWXrCHt
   AAAsofxxxLqKbYOAwLMHG
   AAACgxxxOea
   AAAwfHjDtoJc
   AAAiCfYnbVXWhuvtEx
   AAAkzzQwvf
   AAAdjLalKFapoYAcGE
   AAAthGazmnfK
   etc.

   File B
   AAAwfHjDtoJc
   AAAbjhOJxxxWXrCHt
   AAAiCfYnbVXWhuvtEx
   AAACgxxxOea
   AAAkzzQwvf
   etc.

The task is:What are the lines in B that are not in A?Something like   grep -vf B A

But without the stinking loops!EDIT: File A,B formatting