Set this script to run at various times using launchd to automatically add lines to TaskPaper files if they don't exist. A solution for recurring tasks for plain-text task management.

recurring_taskpaper_task.rb

#!/usr/bin/ruby
# Change to your filepath in lines 9 and 12
# Add your exact search term to line 9
# Add your exact to-do in line 13

require 'time'

today = Time.now.strftime('%Y-%m-%d')
if File.readlines('/Users/USERNAME/Dropbox/Listacular/list.taskpaper', encoding: 'UTF-8').grep(/TERM/).any?
	exit
else
	open('/Users/USERNAME/Dropbox/Listacular/list.taskpaper', 'a') { |f|
  f.puts "- Do this task @due(#{today} 23:00)" + "\n"}
end