convert.rb

#!/usr/bin/env ruby

if ARGV.size < 3
  puts "usage: #{__FILE__} <start_no> <end_no> <output_dir> [quality]"
  exit 1
end

start_no = ARGV[0].to_i
end_no   = ARGV[1].to_i
output_dir = ARGV[2]
quality = ARGV[3].to_i || 100

puts "quality: #{quality}"
(start_no .. end_no).each do |i|
  puts ("converting DSC_%04d.NEF" % [i])
  cmd = "dcraw -6 -c DSC_%04d.NEF | cjpeg -quality %d -dct float > %s/DSC_%04d.jpeg" % [i, quality, output_dir, i]
  system cmd
end