Saint Aardvark writes "It's how the Internet works, and now who invented packet-switching is under dispute. A posthumous paper by British scientist Dr. Donald Davies disputes the claim by Leonard Kleinrock to have invented the technique, saying Kleinrock never took it beyond the case of a single node. Kleinrock, whose lab was the first node on Arpanet, is willing to concede that Davies invented the term "packet-switching.""
egrep patterns are full regular expressions; it uses a fast deterministic
algorithm that sometimes needs exponential space.
-- unix manuals