sciencehabit writes: The first-ever use of interactive computer tasks on a national science assessment suggests that most U.S. students struggle with the reasoning skills needed to investigate multiple variables, make strategic decisions, and explain experimental results. The results are part of the National Assessment of Educational Progress that was given in 2009 to a representative sample of students in grades four, eight, and 12. Link to Original Source
egrep patterns are full regular expressions; it uses a fast deterministic
algorithm that sometimes needs exponential space.
-- unix manuals