Simply script to batch rename photos based on EXIF date and time so that sorting them alphabetically by name sorts the by the time they were taken.

image-rename

#!/usr/bin/ruby

# Sorin Davidoi (sorin.davidoi@gmail.com)

require 'optparse'
require 'exifr'

options, files, conflicts = { }, { }, [ ]


options[:pattern] = '%Y-%m-%d %H.%M.%S'

OptionParser.new do |opts|
	opts.on('-d', '--directory DIR', 'Directory to scan') { |dir| options[:dir] = dir }
	opts.on('-v', '--verbose', 'Enable verbose mode') { options[:verbose] = true }
end.parse!

if options[:dir]
	if Dir.exists?(options[:dir])
		# Change working directory
		Dir.chdir(options[:dir])

		# Iterator through all the files in the working directory
		Dir.foreach(Dir.pwd) do |file_name|
			# Skip current directory and its parent
			next if file_name == '.' || file_name == '..'

			# Only process .jpg files
			if File.extname(file_name).downcase == '.jpg'
				image = EXIFR::JPEG.new(file_name)

				if image.exif?
					if image.exif.date_time
						new_file_name = "#{image.exif.date_time.strftime(options[:pattern])}.jpg"

						# Skip files that already have the desired filename
						unless File.basename(file_name) == File.basename(new_file_name)
							files.has_value?(new_file_name) ? conflicts << file_name : files[file_name] = new_file_name
						end
					else
						puts "#{file_name} does not contain date and time information => Skipping"
					end
				else
					puts "#{file_name} does not contain exif information => Skipping" if options[:verbose]
				end
			else
				puts "#{file_name} not a .jpg file => Skipping" if options[:verbose]
			end
		end

		# Rename files and display conflicts
		files.each { |key, value| puts "#{key} => #{value}" if options[:verbose]; File.rename(key, value) }
		conflicts.each { |file_name| puts "Could not rename #{file_name} : conflict" } unless conflicts.empty?
	else
		puts 'Directory does not exist.'
	end
else
	puts 'No directory specified.'
end