linux-kernel-module-cheat/asciidoctor/extract-header-ids

#!/usr/bin/env ruby

require 'asciidoctor'
require 'asciidoctor/extensions'
require 'pry'

class Main < Asciidoctor::Extensions::TreeProcessor
  def process document
    return unless document.blocks?
    process_blocks document
    nil
  end

  def process_blocks node
    node.blocks.each_with_index do |block, i|
      if block.context == :section
        puts block.id
      end
      process_blocks block if block.blocks?
    end
  end
end

Asciidoctor::Extensions.register do
  treeprocessor Main
end

(Asciidoctor.load_file(ARGV[0])).convert