get_timeline.rb

require "twitter"

client_streaming = Twitter::Streaming::Client.new do |config|
  config.consumer_key = "<your consumer key>"
  config.consumer_secret = "<your consumer secret>"
  config.access_token = "<your access token>"
  config.access_token_secret = "<your access token asecret>"
end

target = client.user("<@Screen Name>") #@で始まる方の名前

client_streaming.user do |object|
  case object
    when Twitter::Tweet
    if(object.user.name == target.name) then
      text = object.text
      puts text
    end
  end
end