#!/usr/bin/env ruby

require ‘fileutils’

stow_dir = ‘/usr/local/stow’
ruby_bin = ‘/usr/local/bin/ruby’

current = `ls -l #{ruby_bin}`
current = current.match(/stow\/(ruby-.*)\/bin\/ruby/)[1]

installed_versions = `ls #{stow_dir}`
installed_versions = installed_versions.split “\n”
installed_versions = installed_versions.select {|x| x =~ /^ruby.*/}

puts “Current Ruby: #{current}”
puts ‘Which version of Ruby would you like to use?’
installed_versions.each_with_index {|version, index| puts “#{index + 1}. #{version}”}
puts ‘ (enter a number): ‘
input = gets.chomp!
input = input.to_i

raise ‘invalid input’ if input == 0 || input > installed_versions.size

new = installed_versions[input - 1]

FileUtils.cd stow_dir
`sudo stow -D #{current} && sudo stow -R #{new}`

result = `ls -l #{ruby_bin}`
result = result.match(/stow\/(ruby-.*)\/bin\/ruby/)[1]
puts “Switched to: #{result}”