gitbook_add_anchors_to_headlines.rb

#!/usr/bin/ruby

require 'fileutils'

# 引数の有無を検証
unless ARGV[0]
  puts "Please specify file(s)."
  exit
end

# 引数の文字列を検証
ARGV.each{|arg|
 unless arg.index(".md") || arg.index(".markdown")
   puts "ERR: Bad file extention: #{arg}"
   puts "Only *.md or *.markdown file(s) is/are  acceptable."
   exit
 end
}

@level1 = /^[#][^#]*[^}]$/
@level2 = /^[#][#][^#]*[^}]$/
@level3 = /^[#][#][#][^#]*[^}]$/

ARGV.each{|arg|
  FileUtils.copy_file(arg, arg + ".bak")

  File.open(arg + ".bak", "r") { |original|
    File.open(arg, "w") { |dist|
      original.each_line { |line| 
        buffer = line

        if @level1.match(buffer.chomp)
          # 既存行の末尾に Gitbook書式 の anchor を追加している
          new_line = "#{buffer.chomp} {##{buffer.slice(2..-1).chomp}}\n" 
          dist.write(new_line)
        elsif @level2.match(buffer.chomp)
          new_line = "#{buffer.chomp} {##{buffer.slice(3..-1).chomp}}\n"
          dist.write(new_line)
        elsif @level3.match(buffer.chomp)
          new_line = "#{buffer.chomp} {##{buffer.slice(4..-1).chomp}}\n"
          dist.write(new_line)
        else
          dist.write(buffer)
        end
      }
    }
  }
}