tonyc

Using strace and lsof to debug blocked processes

You can use strace on a specific pid to figure out what a specific process is doing, e.g.:

strace -fp <pid>

You might see something like:

select(9, [3 5 8], [], [], {0, 999999}) = 0 (Timeout)

epegzz

rakhmad

Setting Up Clojure on OS X

I spent a lot of time trying to find a pretty optimal (for me) setup for Clojure… at the same time I was trying to dive in and learn it. This is never optimal; you shouldn't be fighting the environment while trying to learn something.

I feel like I went through a lot of pain searching Google, StackOverflow, blogs, and other sites for random tidbits of information and instructions.

This is a comprehensive "what I learned and what I ended up doing" that will hopefully be of use to others and act as a journal for myself if I ever have to do it again. I want to be very step-by-step and explain what's happening (and why) at each step.

Step 1: Getting Clojure (1.3)

nono

#!/usr/bin/env ruby

require "openssl"

class BF < Struct.new(:key, :pad_with_spaces)
  def encrypt(str)
    cipher = OpenSSL::Cipher.new('bf-ecb').encrypt
    if pad_with_spaces
      str += " " until str.bytesize % 8 == 0
      cipher.padding = 0

mikehaertl

Learn you a Haskell - In a nutshell

This is a summary of the "Learn You A Haskell" online book under http://learnyouahaskell.com/chapters.

---

1. Introduction

• Haskell is a functional programming language.

mikelikesbikes

(ns katas.change-maker)

(defn num-pairs
  "Returns all combinations of [x y] and (<= x y) where (= cents (+ x y))"
  [cents]

  (for [x (reverse (range 1 (inc (quot cents 2)))) ;; use the range from midpoint to 1 so that we walk the 
                                                   ;; shortest side of the tree first
        :let [y (- cents x)]]
    [x y]))

gr4y

#
# This is the way I configured my ruby environment on ArchLinux.
# 
# I don't like the overhead of rvm, so I use chruby to switch between ruby versions.
# So first you need to install chruby from source: 
# 
# https://github.com/postmodern/chruby#install
#
# To build ruby from source I use ruby-build, so after chruby we install ruby-build:
#

johnmyleswhite

total = 0
N = 300

start_time = time()

for a in 0:(N - 1)
	for b in 0:(N - 1)
		for c in 0:(N - 1)
			if a^2 + b^2 == c^2
				total = total + 1

neilj

var styleFrame = document.createElement( 'iframe' ),
    stylesWaiting = [],
    styleFrameIsReady = false;

styleFrame.setAttribute( 'style',
    'visibility:hidden;position:absolute;top:0;left:0;width:1px;height:1px;' );

styleFrame.addEventListener( 'load', function () {
    var doc = styleFrame.contentDocument,
        html, i, l;

icyleaf

# activerecord-3.0.0/lib/active_record/connection_adapters/mysql_adapter.rb
# Maps logical Rails types to MySQL-specific data types.
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  return super unless type.to_s == 'integer'

  case limit
  when 1; 'tinyint'
  when 2; 'smallint'
  when 3; 'mediumint'
  when nil, 4, 11; 'int(11)'  # compatibility with MySQL default