Strings and regular expressions

• a = "BMW" #-> "BMW"

• b = "#{a} baut #{a}s" #-> "BMW baut BMWs"

• b[4..-6] #-> "baut"

• b[/[N-Z].*[A-M]/] #-> "W baut BM"

• b[/[N-Z].*?[A-M]/] #-> "W baut B"

• =~, match, sub, gsub