Convert Day One (macOS) Journal.txt to Emacs org-mode diary/journal — https://christiantietze.de/posts/2020/10/export-day-one-journal-to-org-mode/

convert_dayone_to_org.rb

#!/usr/bin/env ruby
#
#  convert_dayone_to_org.rb
#  Copyright © 2020 Christian Tietze. All rights reserved. Distributed under the MIT License.
#  
#  Converts a Day One plain text export (Journal.txt) into org-mode journal format. It does
#  - Markdown image conversion from ![](thepath.jpg) to [[thepath.jpg]]
#  - Extraction of images from the front of an entry; moves it right after the property drawer.
#  - Creation of nested year/month/day date sections (see example below)
# 
#  TODOs:
#  - changing the image directory name during import using an option
#  - changing the hash-based image file names to date-time format
#
#  Usage:
#
#   ./convert_dayone_to_org.rb Journal.txt output.org
#
#  Output:
#  
#   * 2020
#   ** 2020-03 March
#   *** 2020-03-14 Saturday
#   **** Here's a diary entry imported from Day One.
#   :PROPERTIES:
#   :CREATED: [2020-03-14 Sat 14:33]
#   :END_PROPERTIES:
#   **** And another one from the same day.
#   :PROPERTIES:
#   :CREATED: [2020-03-14 Sat 19:12]
#   :END_PROPERTIES:
#   ** 2020-06 June
#   *** 2020-06-22 Monday
#   **** Year, month, and day sections are created automatically.
#   :PROPERTIES:
#   :CREATED: [2020-06-22 Mon 08:06]
#   :END_PROPERTIES:

require "date"

input, output, *rest = ARGV
if input.nil?
  STDERR.puts "Usage: #{__FILE__} DAYONE_INPUT_PATH ORG_OUTPUT_PATH"
  STDERR.puts "Missing input file path"
  exit 1
elsif output.nil?
  STDERR.puts "Usage: #{__FILE__} DAYONE_INPUT_PATH ORG_OUTPUT_PATH"
  STDERR.puts "Missing output file path"
  exit 1
end

File.open(output, "w") do |out|
  # Cached values to make sub-headings
  year = nil
  month = nil
  day = nil
  props = {}
  File.readlines(input).each do |line|
    if /\A\t(?<key>\w+):\t(?<value>.*+)$/ =~ line
      # Collect metadata in `props` dictionary
      case key
      when "Date"
        date = DateTime.parse(value)
        props["Created"] = date.strftime("[%Y-%m-%d %a %H:%M]")
        # Convert date lines to new entries in org

        # Output:  "* 2020"
        if year != date.year
          out.puts "* #{date.year}"
          year = date.year
          month = nil
        end

        # Output:  "** 2020-03 March"
        if month != date.month
          out.puts "** #{date.strftime("%Y-%m %B")}"
          month = date.month
        end

        # Output:  "*** 2020-03-12 Thursday"
        this_day = date.strftime("%Y-%m-%d %A")
        if day != this_day
          out.puts "*** #{this_day}"
        end
      else
        props[key] = value
      end
    elsif !props.empty?
      # Produce entry title and metadata
      if line.strip.empty?
        # Skip empty line separator after metadata
      else
        # Add entry heading, handling leading entry images
        cached_image = nil
        if /\A!\[]\((?<path>.+)\)(?<rest>.*)$/ =~ line
          cached_image = "[[./#{path}]]"
          out.puts "**** #{rest}"
        else
          out.puts "**** #{line}"
        end

        # Append property drawer
        out.puts ":PROPERTIES:"
        out.puts(props.map { |key, value| ":" + key.upcase.to_s + ":  " + value.to_s }
                      .join("\n"))
        out.puts ":END_PROPERTIES:"
        props = {}

        if !cached_image.nil?
          out.puts ""
          out.puts cached_image
        end
      end
    else
      line = line.gsub(/!\[\]\((.+)\)/) { "[[./#{$1}]]" }
      out.puts line
    end
  end
end