vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

ryerh

注意：本文内容适用于 Tmux 2.3 及以上的版本，但是绝大部分的特性低版本也都适用，鼠标支持、VI 模式、插件管理在低版本可能会与本文不兼容。

Tmux 快捷键 & 速查表 & 简明教程

启动新会话：

tmux [new -s 会话名 -n 窗口名]

恢复会话：

mlanett

HTTP status code symbols for Rails

Thanks to Cody Fauser for this list of HTTP responce codes and their Ruby on Rails symbol mappings.

Status Code Symbol
1xx Informational
100 :continue
101 :switching_protocols
102 :processing

justintv

# If you work with git, you've probably had that nagging sensation of not knowing what branch you are on. Worry no longer!

export PS1="\\w:\$(git branch 2>/dev/null | grep '^*' | colrm 1 2)\$ "

# This will change your prompt to display not only your working directory but also your current git branch, if you have one. Pretty nifty!

# ~/code/web:beta_directory$ git checkout master
# Switched to branch "master"
# ~/code/web:master$ git checkout beta_directory
# Switched to branch "beta_directory"

otobrglez

# Simple Recommendation Engine in Ruby
# Visit: http://otobrglez.opalab.com
# Author: Oto Brglez <otobrglez@gmail.com>

class Book < Struct.new(:title)

  def words
    @words ||= self.title.gsub(/[a-zA-Z]{3,}/).map(&:downcase).uniq.sort
  end

LeCoupa

#!/bin/bash
#####################################################
# Name: Bash CheatSheet for Mac OSX
# 
# A little overlook of the Bash basics
#
# Usage:
#
# Author: J. Le Coupanec
# Date: 2014/11/04

elfassy

#=Navigating=
    visit('/projects')
    visit(post_comments_path(post))

#=Clicking links and buttons=
    click_link('id-of-link')
    click_link('Link Text')
    click_button('Save')
    click('Link Text') # Click either a link or a button
    click_on('Button Value')

zjhiphop

##分布式系统(Distributed System)资料

---

#####希望转载的朋友，你可以不用联系我．但是一定要保留原文链接，因为这个项目还在继续也在不定期更新．希望看到文章的朋友能够学到更多．

• 《Reconfigurable Distributed Storage for Dynamic Networks》

介绍:这是一篇介绍在动态网络里面实现分布式系统重构的paper.论文的作者(导师)是MIT读博的时候是做分布式系统的研究的,现在在NUS带学生,不仅仅是分布式系统,还有无线网络.如果感兴趣可以去他的主页了解.

joyrexus

Sans jQuery

Events

// jQuery
$(document).ready(function() {
  // code
})