mattknox

Let's say you have a Bash shell script, and you need to run a series of operations on another system (such as via ssh). There are a couple of ways to do this.

First, you can stage a child script on the remote system, then call it, passing along appropriate parameters. The problem with this is you will need to manually keep the remote script updated whenever you change it -- could be a bit of a challenge when you have something to execute on a number of remote servers (i.e., you have a backup script running on a central host, and it needs to put remote databases in hot backup mode before backing them up).

Another option is to embed the commands you want to run remotely within the ssh command line. But then you run into issues with escaping special characters, quoting, etc. This is ok if you only have a couple commands to run, but if it is a complex piece of Bash code, it can get a bit unwieldy.

So, to solve this, you can use a technique called rpcsh -- rpc in shell script, as follows:

First, place th

mattknox

Wisdom From Merlin

Or: “Everybody likes being given a glass of water.”

It's only advice for you because it had to be advice for me.

This odd collection began life as a challenge for a podcast 

mattknox

Gin, Television, and Social Surplus, or, “Looking for the Mouse”

Clay Shirky / April 26, 2008

transcription of a speech [Clay Shirky] gave at the Web 2.0 in 2008, emphasis by @jm3

I was recently reminded of some reading I did in college, way back in the last century, by a British historian arguing that the critical technology, for the early phase of the industrial revolution, was gin.

The transformation from rural to urban life was so sudden, and so wrenching, that the only thing society could do to manage was to drink itself into a stupor for a generation. The stories from that era are amazing-- there were gin pushcarts working their way through the streets of London.

And it wasn't until society woke up from that collective bender that we actually started to get the institutional structures that we associate with the industrial revolution today. Things like public libraries and museums, increasingly broad education for children, elected leaders--a lot of th

mattknox

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

mattknox

Building a Maintainable, Agile Architecture for Realtime, Transactional Apps

A maintainable application architecture requires that the UI only contain the rendering logic and execute queries and mutations against the underlying data model on the server. A maintainable architecture must not contain any logic for composing "app state" on the client as that would necessarily embed business logic in the client. App state should be persisted to the database and the client projection of it should be composed in the mid tier, and refreshed as mutations occur on the server (and after network interruption) for a highly interactive, realtime UX.

With GraphQL we are able to define an easy-to-change application-level data schema on the server that captures the types and relationships in our data, and wiring it to data sources via resolvers that leverage our db's own query language (or data-oriented, uniform service APIs) to resolve client-specified "queries" and "mutations" against the schema.

We use GraphQL to dyn

mattknox

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

mattknox

Developer Cheat Sheets

This are my cheat sheets that I have compiled over the years. Tired of searching Google for the same things, I started adding the information here. As time went on, this list has grown. I use this almost everyday and this Gist is the first bookmark on my list for quick and easy access.

I recommend that you compile your own list of cheat sheets as typing out the commands has been super helpful in allowing me to retain the information longer.

mattknox

# Ever get tired of people messing with your ruby classes?
# now you can put the hammer down and stop them. Just 
# include this module and no one will be able to modify the 
# class implementation or any instance implementations.


module Stop
  module CantTouchThis
    def self.included(mod)

mattknox

(ns sudoku
  (:refer-clojure :exclude [==])
  (:use clojure.core.logic))

(defn get-square [rows x y]
  (for [x (range x (+ x 3))
        y (range y (+ y 3))]
    (get-in rows [x y])))

(defn init [vars hints]

mattknox

require "rubygems"
require "rbench"
require "set"

RANGE = (1..1000)
ARRAY = RANGE.to_a
SET   = Set.new(ARRAY)
HASH  = ARRAY.inject({}) {|m, x| m[x] = true; m}

WORST_CASE_COMPLEXITY = ARRAY.size + 1