如何使用ARGV*，如何在其中实现命令行参数

# script.rb
puts "Script name: #{$0}"
puts "Number of arguments: #{ARGV.size}"

ARGV.each_with_index do |arg, index|
  puts "Argument #{index}: #{arg}"
end

# backup.rb
require 'fileutils'

if ARGV.empty?
  puts "Usage: ruby backup.rb <directory>"
  exit
end

directory = ARGV[0]

if File.exist?(directory)
  FileUtils.cp_r(directory, "#{directory}_backup")
  puts "Backup created for #{directory}"
else
  puts "Directory #{directory} does not exist."
end

ruby backup.rb /path/to/directory

if ARGV.empty?
  puts "Usage: ruby script.rb <required_argument>"
  exit(1)
end

expected_args = 2
if ARGV.size != expected_args
  puts "Usage: ruby script.rb <arg1> <arg2>"
  exit(1)
end

if ARGV.size > 0
  directory = ARGV[0]
  unless File.directory?(directory)
    puts "Error: #{directory} is not a valid directory."
    exit(1)
  end
end