Git diff changes staged

# On branch master
# Changes to be committed:
#   (use "git reset HEAD ..." to unstage)
#
#       modified:   app/views/matriculations/new.html.erb

To see changes,

git diff --cached (pre-1.6)
git diff --staged

Rails, RedCloth, textilize gotcha

# This doesn't work! It returns html in pure strings and not the html elements!

textilize @blog.content

# Need this extra step.

sanitize(textilize @blog.content)

**UPDATED**

The problem lies that Rails 3 ERB uses h() helper by default

<\%= xxx %>
<\%= h(xxx) %>

To get past this use context_tag() or raw()

xxx = content_tag(:p, "blah")
<\%= xxx %>

xxx = "<\p>blah<\/p>"
<\%= raw xxx %>

Using Fn triggered blue numpad keys for navigation on your laptop

Laptop keys are usually cramped and accessing the usual arrow and page keys are a hassle. I find it useful to use the "numpad" triggered by Fn key.

Fn + 7 = Home
Fn + 1 = End
Fn + 9 = Pg Up
Fn + 3 = Pg Down
Fn + 8 = Up
Fn + 2 = Down
Fn + 4 = Left
Fn + 6 = Right

Bringing jobs into background in terminal

# Suspend job
CTRL + z

# View jobs
jobs

# Bring job into background
%1 &

# Bring job into foreground
%1

Open files at line number in Vim

:e PATH_TO_FILE:LINE_NO

Eg.
:e app/models/user.rb:10

Command line calculator

bc -l

Installing Flash & Java on Firefox & Chromium browsers

1. Install Flash & Java
2. Symlink executables to browser plugin folder

Java

sudo ln -s  JAVA_PLUGIN_PATH BROWSER_PLUGIN_PATH

Flash

sudo ln -s FLASH_PLUGIN_PATH BROWSER_PLUGIN_PATH

To find JAVA_PLUGIN_PATH

locate libnpjp2.so
/usr/lib/jvm/java-6-sun-1.6.0.16/jre/lib/i386/libnpjp2.so

To find FLASH_PLUGIN_PATH

locate libflashplayer.so
/usr/lib/flashplugin-installer/libflashplayer.so

And BROWSER_PLUGIN_PATH is

# Firefox 
/usr/lib/mozilla/plugin/

# Chromium 
/usr/lib/chromium/plugin/

#Google-Chrome 
/opt/google/chrome/plugin/

NOTE: symlinks must be updated after every java upgrade

Factory Girl has many associations gotcha

Suppose Post has many Items

class Post < ActiveRecord::Base
  has_many :items
end

class Item < ActiveRecord::Base
  belongs_to :post
end

When setting up data for tests using factory girl

Factory.define :item do
  u.post {|p| p.association(:post)}
end

Don't do this!

@post.items << Factory(:item)

Factory will create an item with another post_id and this will not be automatically changed to @post.id. Instead do this.

Factory(:item, :post => @post)

Undo last Git commit with last commited files for edit

git reset --soft HEAD^
git reset

Running Shoulda & Factory Girl in Rails 3

Rails 3 uses Bundler gem to handle gem dependencies. Encountered some problems with Shoulda and Factory Girl.

# Gemfile

group :test do
  gem "shoulda"
  gem "factory_girl"
end

Shoulda and Factory Girl macros are not loaded so I had to require the gems in test/test_helper.rb

# test/test_helper.rb

require 'shoulda'
require 'factory_girl'
Factory.definition_file_paths = [ File.join(Rails.root, 'test', 'factories') ]
Factory.find_definitions

Problem installing sqlite3-ruby gem

Never learnt my lessons. Encountered this so many times.

sudo gem install sqlite3-ruby

Building native extensions.  This could take a while...
ERROR:  Error installing sqlite3-ruby:
        ERROR: Failed to build gem native extension.

/usr/bin/ruby1.8 extconf.rb
checking for fdatasync() in -lrt... yes
checking for sqlite3.h... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

The solution is to make sure the following library's installed!

sudo apt-get install libsqlite3-dev

Review git commits in terminal

git log -u HEAD^..HEAD