Switch between multiple Heroku accounts with ease

gistfile1.rb

#!/usr/bin/env ruby

require 'fileutils'

def die(code=1)
  $stderr.puts 'Usage: herokusu [--list | --switch user]'
  exit code
end

HEROKU_PATH = File.expand_path '~/.heroku'
CREDENTIALS_PATH = File.join HEROKU_PATH, 'credentials'

die if ARGV.length > 2

option = ARGV.shift

if ARGV.length == 0 or option == '--verbose'
  real_file = File.readlink CREDENTIALS_PATH
  user = real_file.split('.')[-1]
  print user
  if option == '--verbose'
    File.open(CREDENTIALS_PATH) do |f|
      email = f.gets.chomp
      print " (#{email})"
    end
  end
  puts
  exit 0
end

if option == '--list'
  Dir.chdir(HEROKU_PATH) do
    Dir['credentials.*'].each do |f|
      user = f.split('.')[-1]
      puts user
    end
  end
  exit 0
elsif option == '--switch'
  die if ARGV.length != 1
  user = ARGV.shift
  credentials = File.join HEROKU_PATH, "credentials.#{user}"
  Dir.chdir(HEROKU_PATH) do
    FileUtils.ln_sf credentials, CREDENTIALS_PATH
  end
  puts "Switched to #{credentials}"
end