twitter_unfollow.rb

require 'twitter'
require 'csv'
require 'date'

# Define the cut off, in days:
tweet_cliff = 180

client = Twitter::REST::Client.new do |c|
  c.consumer_key        = ''
  c.consumer_secret     = ''
  c.access_token        = ''
  c.access_token_secret = ''
end

following_ids = client.friend_ids.to_a
bye_bye_users = client.users(following_ids).select do |user|
  user.status.created_at < (Date.today.to_date - tweet_cliff).to_time
end

# Remove bye_bye_users
client.unfollow(bye_bye_users)

puts "Unfollowed #{bye_bye_users.count}:"

CSV.open('twitter_unfollowing.csv', 'wb') do |csv|
  csv << %w(user_id, screen_name, last_tweet, last_tweet_date)
  
  bye_bye_users.sort! { |a, b| a.screen_name.downcase <=> b.screen_name.downcase }

  bye_bye_users.each do |u|
    csv << [u.id, u.screen_name, u.status.text, u.status.created_at]
  end
end