Jon Arrien

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Fixing Gephi on MacOSX

If you want to use the visualization software Gephi on Mac OSX, but it hangs on launch, luckily, there is a solution.

Just install this Java update from Apple:
Java for OS X 2014-001

Screenshot of gephi:

Managing MongoDB

MongoDB is an awesome document database to store information for you apps. But everyone that has already use it, knows MongoDB console is not very pleasant to work with. Here I share I few solutions that can make it easier.


Native Mac OSX GUI application for mongodb.



Shell-centric cross-platform MongoDB management tool.



The single-file MongoDB admin app.


Pow: rake not found

Captura de pantalla 2014-05-26 a la(s) 08.29.13

If you use pow as your development server, may be you’ve encountered an issue with Rake. You’ve run “bundle install”, but pow still is not able to find the gem.

If this is your case, just run this command from your projects root path to load you environment in .powenv:
[cc lang=”bash”]
rvm env > .powenv

New in RSpec 3

  • Removed support for Ruby 1.8.6 & 1.9.1
  • Improved Ruby 2.0 support
  • New rspec-support gem
  • Ability to disable all of the monkey patching mode with one option
  • :each and :all have now aliases => :example and :context
  • describe, shared_examples_for and shared_context methods under RSpec module.
  • xdescribe,  xcontext and xit for examples
  • fdescribe, fcontext and fit to set :focus => true
  • Changes in pending, introduced skip
  • Added is_expected
  • Groups can be ordered individually
  • Improvements in rspec —init
  • New —dry-run CLI option
  • Completely new formatter API
  • Removed expect_with  :stdlib. Instead explicit :text_unit and :minitest.
  • Added define_derived_metadata to tag all specs in a group
  • Ability to chain multiple matchers togethers using and or or (Aliases for & and | )
  • match matcher can be used for data structures
  • New all matcher
  • New be_between matcher
  • Boolean matchers renamed to be_truthy and be_falsey
  • match_array renamed to contain_exactly
  • Improved integration with minitest
  • Removed mock and stub aliases of double
  • File-type inference disabled by default




Reserved words in Rails

A simple web app to check reserved words in Rails:

Neo4j & Cypher


Neo4j is a Property-Graph database that consists of labeled nodes and relationships each with properties.

Nodes are just data records, and properties are simple key:value pairs that allow you to store information in Neo4j. Properties can be attached to both nodes and relationships and are referred to by or

There is no schema, just structure.

Cypher instead, is a declarative, SQL inspired language for describing patterns in graphs. It allows us to describe what we get from a graph database without requiring us to describe exactly how to do it.

Example query to retrieve a species:
[cc lang=”sql”]
MATCH (s:Species)
WHERE s.scientific_name = “Canis Lupus”

Example query top return all the species living in a Habitat:
[cc lang=”sql”]
MATCH (s:Species)-[:LIVE_IN]->(h:HabitatType {name: “Sierra de Gredos”} )
RETURN s.scientific_name;

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