For a big file filled with atom entries, spit out the epoch of each atom entry's updated timestamp. Output to stdout. so pipe it to your file.

atom_timeseries.rb

#!/usr/bin/ruby
# usage: ./atom_timeseries.rb file
# For a big file filled with atom entries, spit out 
# the epoch of each atom entry's updated timestamp.
# Output to stdout. so pipe it to your file.

require 'Time'

file = File.new(ARGV[0], "r")
while (line = file.gets)
  if line =~ /<updated>(.*)<\/updated>/
    puts Time.parse((/<updated>(.*)<\/updated>/.match(line))[1]).to_i
  end
end

file.close