taka328w · January 15, 2012 14:02 · Jan 24, 2012 · Jan 15, 2012
diff --git a/gistfile1.rb b/gistfile1.rb
@@ -1,4 +1,4 @@
-# -*- encoding: utf-8 -*-
+# coding: utf-8
 require 'rubygems'
 require 'aws-sdk'
 

diff --git a/gistfile1.rb b/gistfile1.rb
@@ -0,0 +1,23 @@
+# -*- encoding: utf-8 -*-
+require 'rubygems'
+require 'aws-sdk'
+
+config = {:access_key_id => 'アクセスキー ID',
+          :secret_access_key => 'シークレットアクセスキー'}
+AWS.config(config)
+
+hosts = []
+hosts << "127.0.0.1\tlocalhost localhost.localdomain"
+AWS::EC2.new.instances.each do |instance|
+  next unless instance.status == :running
+  tags = instance.tags.to_h
+  hosts << "#{instance.private_ip_address}\t#{tags["Name"]}"
+end
+
+# バックアップを取って、差分があれば差し替え
+`cp -p /etc/hosts /etc/hosts.bak`
+open("/etc/hosts.new", "w") {|f| f.write hosts.join("\n")+"\n"}
+is_same = system("diff -q /etc/hosts.new /etc/hosts > /dev/null 2>/dev/null")
+unless is_same
+  `cp -p /etc/hosts.new /etc/hosts`
+end