iONiUM writes: "In an interesting problem with physical currency, Iran is now running out of hard currency, due to a combination of inflation, and "Koenig & Bauer AG of Würzburg, Germany, also says it has not responded to an Iranian request for bids to make the presses to print new rials." Perhaps they should switch to BitCoin."
egrep patterns are full regular expressions; it uses a fast deterministic
algorithm that sometimes needs exponential space.
-- unix manuals