A template for a new ruby thor-based command-line utility

thor-template.rb

#!/usr/bin/env ruby
#
# THOR template

$PROG = File.basename($PROGRAM_NAME)
$DIR  = File.dirname($PROGRAM_NAME)

# Possibly modify the LOAD_PATH
# $LOAD_PATH << File.join(__dir__, '..', 'lib/migrations')

require 'thor'

# require 'pry-byebug' # uncomment for debugging

class MyNewCLI < Thor

  class_option :verbose,           aliases: '-v', type: :boolean, default: false, desc: "Be verbose"
  class_option :norun,             aliases: '-n', type: :boolean, default: false, desc: "No run -- don't make any changes"
  class_option :debug,             aliases: '-d', type: :boolean, default: false, desc: "Debug mode"

  desc "action1 [ARGUMENTS ...]", "Perform action1"

  def action1(*arguments)
    # ...
  end

  desc "action2", "Perform action2"

  def action2(*arguments)
    # ...
  end

  desc "action3 ARG...", "Perform action3 on ARG .."

  ## some options specific to this action
  # option :primary_key,  aliases: '-p', type: :boolean, default: false, desc: "Only show the primary keys"
  # option :id_columns,   aliases: '-i', type: :boolean, default: false, desc: "Only show non-PK id columns"
  # option :associations, aliases: '-a', type: :boolean, default: false, desc: "Only show the association keys"
  # option :foreign_keys, aliases: '-f', type: :boolean, default: false, desc: "Only show foreign_keys"
  # option :indexes,      aliases: '-x', type: :boolean, default: false, desc: "Only show the indexes"

  def action3(*arguments)
    # ...
  end

  no_commands do

    def root_dir
      @root_dir ||= get_root_config_dir
    end

    def lib_dir
      File.join(root_dir, 'lib')
    end

    def get_root_config_dir
      loop do
        this_dir = Dir.pwd
        return this_dir if File.exist?('config/environment.rb')
        case this_dir
        when 'config', %r{/config$}
          raise "Cannot find 'environment.rb' within 'config'!"
        when '/', ''
          raise "Cannot find 'config/environment.rb'!"
        else
          begin
            Dir.chdir('..')
          rescue
            raise "chdir '..' failed! Cannot find 'config/environment.rb'!"
          end
        end
      end
    end

    def add_load_path(dir)
      $LOAD_PATH << dir unless $LOAD_PATH.include?(dir)
    end

    def initialize_rails
      unless defined?(RAILS_ENV)
        add_load_path root_dir
        require 'config/environment'
      end
    end

    def print_in_columns_sorted_vertically(array)
      return if array.empty?
      data = array.sort
      col_width = (data.map { |el| el.to_s.size }.max || 1) + COLUMN_GUTTER_WIDTH
      num_cols = [terminal_width / col_width, 1].max
      num_rows = [data.size / num_cols, 1].max
      0.upto(num_rows - 1) do |row_index|
        str = ''
        0.upto(num_cols - 1) do |col_index|
          index = row_index + col_index * num_rows
          break unless index < data.size
          str << sprintf("%-#{col_width}s", data[index] || '')
        end
        puts str.rstrip
      end
    end

  end
end

MyNewCLI.start(ARGV)