alana2.rb

#!/usr/bin/env ruby

puts "Why is the FBI after you?"
# optional, but you can chain the downcase here
text = gets.chomp.downcase

# the default parameter for String#split is ' ', so you can omit it
words = text.split
# note that since text was only used here, you could have just said:
#words = gets.chomp.downcase.split

puts "What information needs to be destroyed?"
redact = gets.chomp.downcase

# I'm going to go different way this time, I'm going to create an array
# which I will use to build the final string
final_words = []

words.each do |word|
  if word == redact
    # put REDACTED into the array
    final_words.push('REDACTED')
  else
    # otherwise, put the uncensored word into the array
    final_words.push(word)
  end
end

# finally, display the string
puts final_words.join(' ')