downloader.rb

require 'zlib'
require 'open-uri'

file_name = "hello.tar.gz"
download_url = "https://storage.googleapis.com/golang/go1.5.2.linux-amd64.tar.gz"

File.open(file_name, "wb") do |f|
  f.write(Zlib::GzipReader.new(open(download_url)).read)
end
end

File.open(file_name, "r") do |f|
  g = Zlib::GzipReader.open(f)
  puts g.read
  g.close
end