Scans a folder of photos looking for save timestamps in XMP header

xmp_scan.rb

#! /usr/bin/env ruby
#
# Scans a folder of photos looking for save timestamps in XMP header
#

require 'nokogiri'

dir = ARGV[0]

Dir.foreach(dir) do |file|
  next if file[0] == '.'

  xmp = Nokogiri::XML(`exiftool -xmp -b "#{File.join(dir, file)}"`)
  xmp = xmp.xpath(
    "//x:xmpmeta/rdf:RDF/rdf:Description/xmpMM:History/rdf:Seq/rdf:li",
    'xmpMM' => "http://ns.adobe.com/xap/1.0/mm/",
    'x' => 'adobe:ns:meta/',
    'rdf' => "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  )

  xmp.each do |element|
    if element['stEvt:when']
      puts "#{file}, #{element['stEvt:when']}"
    end
  end
end