# File lib/thin/controllers/controller.rb, line 143
        def tail(file)
          cursor = File.exist?(file) ? File.size(file) : 0
          last_checked = Time.now
          tail_thread = Thread.new do
            Thread.pass until File.exist?(file)
            File.open(file, 'r') do |f|
              loop do
                f.seek cursor
                if f.mtime > last_checked
                  last_checked = f.mtime
                  contents = f.read
                  cursor += contents.length
                  print contents
                  STDOUT.flush
                end
                sleep 0.1
              end
            end
          end
          sleep 1 if File.exist?(file) # HACK Give the thread a little time to open the file
          tail_thread
        end