freeman ericchen

JS作用域有哪些，分别有什么区别？
说一说cookie sessionStorage localStorage 区别
怎么添加事件监听，有哪些方式，请分别写出
const arr = [1, [2, [3, 4]]], 请写一个函数实现将数组arr扁平化。
实现一个串行的后台接口加载函数, 要求上一个接口加载完毕，再加载下一个接口
HTTP 常用的状态码及使用场景
HTTP 常用的请求方式，区别和用途
跨域有哪些解决方案？各有什么区别。

将当前目录下过去30天的目录移动指定目录下

find . -mindepth 1 -type d -mtime +30 | xargs -i mv {} /home/bu/date_30/

1.当前时间24小时—当前时间（昨天-今天）

find . -mtime 0

2.当前时间48小时前–当前时间24小时前(前天-昨天)

今天早上起来发现登录不进去vps了，然后通过vps web端将root密码重新设置，检查/etc/passwd 文件被加入下面user REDIS0006?, Google了一下，原来是利用了redis的漏洞，由于偷懒将redis没有设置密码且以root权限运行，也没有设置只允许本地访问 (bind 127.0.0.1未打开)导致黑客可以修改/etc/passwd文件

Redis后门植入分析报告(http://drops.wooyun.org/tips/10462)
Redis 未授权访问漏洞被利用，服务器登陆不上(http://www.cnblogs.com/langdashu/p/5392128.html)
Redis配合ssh-keygen渗透测试 (http://www.jianshu.com/p/97f4bb96612f)

添加源并安装

vi /etc/apt/sources.list.d/pgdg.list
添加下面内容到文件：deb http://apt.postgresql.org/pub/repos/apt/ wheezy-pgdg main
添加签名key: wget http://www.postgresql.org/media/keys/ACCC4CF8.asc, apt-key add ACCC4CF8.asc
更新源： apt-get update
安装： sudo apt-get install postgresql-9.4
配置验证方式： sudo vi /etc/postgresql/9.4/main/pg_hba.conf 将peer改成md5, 然后重启: sudo service postgresql restart

配置数据库

登录数据库： sudo -u postgres psql template1
创建用户名： CREATE USER dbuser WITH PASSWORD 'password';

启动sidekiq

bundle exec sidekiq -c 10 -e production -L log/sidekiq.log -d

队列查询

# See workers
Sidekiq::Client.registered_workers

# See queues
Sidekiq::Client.registered_queues

导出: select tag,counter into OUTFILE '/var/lib/mysql/tags.csv' FIELDS TERMINATED BY ',' FROM tag_counters ORDER BY counter desc;

导入到其它数据库: LOAD DATA INFILE '/Users/eric/Downloads/tags.csv' INTO TABLE tags FIELDS TERMINATED BY ',' (tag, counter);

#####首先要激活在namecheap上购买的ssl服务

生成SSL证书获取CSR bash openssl req -new -key yourdomain.pem -out yourdomain.csr , 然后按照提示输入信息即可
执行cat yourdomain.csr 内容大概如下 ``` -----BEGIN CERTIFICATE REQUEST----- MIICxDCCAawCAQAwfzELMAkGA1UEBhMCQ04xEDAOBgNVBAgMB0JlaWppbmcxEDAO BgNVBAcMB0JlaWppbmcxDjAMBgNVBAoMBUJpZ2ZhMRcwFQYDVQQDDA55b3VyZG9t YWluLmNvbTEjMCEGCSqGSIb3DQEJARYUYWRtaW5AeW91cmRvbWFpbi5jb20wggEi MA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC9fsxThwLzCd54s2GMUcjlleCj LTf9bYGQyIjn+6z7kJbDbcrkbZxMysfRnFLa6u5oK7S9PQfGHK/gZeHfSLXbD/GL wi171tZpnQHjfLjMbHEUEUCFQD7ueek/v3/Tr+T0+em1gQt/93K2dqv7Cx+bupwc zNkQmqNgqslC4sdKQZjLUIHYLr/j8lQQLOOn9/PiuNOGCTaK5g9TA20oVCjpJZuf

	class LockManager
	def self.with_transaction_lock(lock_name)
	lock_id = Zlib.crc32(lock_name.to_s)
	ActiveRecord::Base.transaction do
	ActiveRecord::Base.connection.execute("SELECT pg_advisory_xact_lock(#{lock_id})")
	yield
	end
	end

	def self.with_session_lock(lock_name)

	# Usage example:
	#
	# s = PinterestSpammer.new
	# s.sign_in 'your_account_email', 'your_account_password'
	# s.get_boards # get boards list, that contains board_id (for example - 455708124733779520)
	# s.create_pin(455708124733779520, 'https://xyz.xyz/', 'http://rubyonrails.org/images/rails.png', 'Spammer!')
	#
	#
	require 'mechanize'
	class PinterestSpammer

	#need replace with double quote instead of single quote
	test_string <<EOF
	Specifications:\n Brand: Brand new and high quality\n Style: Sexy black lace mask\n\nItem Description\n 1. Suit for all kinds of occasion like party and Halloween.\n 2. Matching your clothes well.\n\nPackage Includes\n1 x Masquerade Mask
	EOF
	test_string.gsub(/(\\r\\n)\|\\n/, "\n")