eval "$(aws-env XXX)" することで、 credential から XXX profile を探して AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_DEFAULT_REGION をセット

aws-env

#!/usr/bin/env ruby

class Parser
  # python's config format: https://docs.python.org/2/library/configparser.html
  def self.parse(contents)
    sections = {}
    contents.each_line do |line|
      case line
      when /\s*[#;]/, /^\s*$/
        # skip
      when /^\s*\[(.*)\]/
        sections[$1] = {}
      when /^\s*(.*)(?:=|: )(.*)\s*$/
        section = sections.keys.last
        sections[section][$1] = $2
      end
    end
    sections
  end

  def self.load_file(file)
    content = File.open(file).read
    parse(content)
  end
end


profile_name = ARGV[0] || "default"

credential_file = File.expand_path(".aws/credentials", ENV['HOME'])
unless File.exists? credential_file
  abort "Missing credential file: #{credential_file}"
end

profiles = Parser.load_file(credential_file)
profile = profiles[profile_name]
if profile.nil?
  abort "Can't find: #{profile_name}"
end

config_file =
  ENV.fetch('AWS_CONFIG_FILE', File.expand_path(".aws/config", ENV['HOME']))
if File.exists? config_file
  configs = Parser.load_file(config_file)
  config_profile = configs["profile #{profile_name}"] || configs["default"] || {}
  if config_profile["region"]
    default_region = config_profile["region"]
  end
end

puts <<-SHELL
# [#{profile_name}]
export AWS_ACCESS_KEY_ID='#{profile["aws_access_key_id"]}'
export AWS_SECRET_ACCESS_KEY='#{profile["aws_secret_access_key"]}'
SHELL
puts <<-SHELL if default_region
export AWS_DEFAULT_REGION='#{default_region}'
SHELL