gistfile1.txt

#!/usr/bin/ruby
# cpioxz.rb
# Jonathan D. Stott <jonathan.stott@gmail.com>

if ARGV.empty?
  warn "Usage: #{$0} directory [directories+]"
  exit 1
end

ARGV.each do |dir|
  next unless File.directory?(dir)
  directory = dir.sub(/\/$/,'')

  xz = "#{directory}.cpio.xz"

  system("find #{directory} -type f -print0 | xargs -0 sha1sum >#{directory}.sha1")
  system("find #{directory} #{directory}.sha1 -type f -print0 | cpio --create --quiet --null --format=crc | xz --best -Csha256 >#{xz}") || abort("Failed to write cpio")
  system("xzcat #{xz} | cpio --quiet --extract --only-verify-crc") || abort("failed to verify crc")
end