Find a random plain text file in a directory

random_file.rb

#!/usr/bin/env ruby

# Usage: random_file.rb [options]
#     -d, --dir [VALUE]                Path to the note archive. Default: the current working directory.
#     -c, --count [VALUE]              Amount of unique random notes to fetch
#     -h, --help                       Prints this help

require "optparse"

CURRENT_PATH = Dir.pwd

options = {
  directory: CURRENT_PATH,
  amount: 1
}

parser = OptionParser.new do |o|
  o.banner = "Usage: #{__FILE__} [options]"

  o.on("-d", "--dir [VALUE]", "Path to the note archive. Default: the current working directory (#{CURRENT_PATH})") do |val|
    path = File.expand_path(val.to_s)
    if File.exist?(path)
      options[:directory] = path
    else
      abort %Q{Directory at path #{path} does not exist}
    end
  end

  o.on("-c", "--count [VALUE]", "Amount of unique random notes to fetch") do |val|
    options[:amount] = val.to_i
  end

  o.on_tail("-h", "--help", "Prints this help") do
    STDOUT.puts o
    exit
  end
end

parser.parse!

# puts options

EXTENSIONS = ["markdown", "md", "mmd", "txt", "text"]

def extension(path)
  filename = File.basename(path)
  filename_without_ext = File.basename(path, ".*")
  # Take the remainder, without the dot, after the filename
  return filename[filename_without_ext.length + 1 .. -1]
end

results = []
Dir.chdir(options[:directory]) do
  all_files = Dir.glob("*").select { |f| EXTENSIONS.include?(extension(f))}

  options[:amount].times do
    remainder = all_files - results
    next_file = remainder.sample
    break if next_file.nil?
    results << next_file
  end
end

STDOUT.puts results

Example

Command

$ ruby random_note.rb -d ~/Archive/ -c 12

Example output:

201701161531 Automatic version numbering.md
201708211509 Buffer 3rd Wave Feminismus.txt
201309271825 Portable Kanban board.md
201607031406 User login session management in the Fabric app.md
201602201129 ambient interface.txt
201707272141 The 7 habits of highly effective artists.txt
201708231440 Why does ReSwift Middleware have dispatch.txt
2010-11-23_0757_R1_How to make introductions.md
201907060747 Send HTTP request from Ruby.txt
201611201032 Discipline necessitates purpose.md
201803221749 chmod settings for web server scripts.txt
201606050858 Function declaration kinds in JavaScript.txt

Sorted Example

Command, piping the output to sort:

$ ruby random_note.rb -d ~/Archive/ -c 12 | sort

Example output:

2010-11-23_0757_R1_How to make introductions.md
201309271825 Portable Kanban board.md
201602201129 ambient interface.txt
201606050858 Function declaration kinds in JavaScript.txt
201607031406 User login session management in the Fabric app.md
201611201032 Discipline necessitates purpose.md
201701161531 Automatic version numbering.md
201707272141 The 7 habits of highly effective artists.txt
201708211509 Buffer 3rd Wave Feminismus.txt
201708231440 Why does ReSwift Middleware have dispatch.txt
201803221749 chmod settings for web server scripts.txt
201907060747 Send HTTP request from Ruby.txt