Tempfile URL block open

url_tmp_open.rb

require 'tempfile'
require 'open-uri'

url = "http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.1"
tmp = Tempfile.new('foo')
# while this is running in irb, check out /tmp/foo*

open(url) do |f|
  f.each_line {|line| tmp.write line}
end

tmp.rewind

# lazy fast forward by one line
tmp.each_line.first

puts tmp.each_line.first
# => "Author: Linus Torvalds <torvalds@linux-foundation.org>\n