Simple class to prompt a user on the command line for a response.

user_input.rb

class UserInput
  # Prompt for confirmation, exiting if not an affirmative.
  def self.confirm!(message)
    unless confirm(message)
      STDERR.write("cancelling...\n")
      exit
    end
  end

  # Prompt for confirmation, returning a boolean indicating user's preference.
  def self.confirm(message)
    response = prompt(message + "\ny / N: ").strip.downcase
    response == "y"
  end

  # Prompt the user and await a response.
  def self.prompt(message)
    STDERR.write(message)
    STDIN.gets
  end
end