you should always

has_many :join_models, :dependent => :destroy

When you have a hook in your Capistrano file that dumps your remote database, you might not want it to dump each time you deploy (say, you're experimenting with staging and don't want ten dumps an hour). How to skip dump creation:

Capistrano 2

In your Capistrano file:

before 'deploy:update_code', 'db:dump' unless fetch(:skip_dump, false)

The second parameter of fetch sets a default value if skip_dump is not defined.

In your terminal:

cap staging deploy -S skip_dump=true

The -S must be a capital letter t...

When you edit text in Balsamiq Mockups, you can define inline styles like this:

| Bold | Some *bold* text |
| Italics | Some _italic_ text |
| Blue underlined hyperlink | Some [linked] text |

Note that most Balsamiq widgets display with a bold font by default, so you won't usually see a difference when a piece of text is explicitly marked up as bold.

Ubuntu natty introduced new "invisible" scrollbars for GTK programs such as gEdit or Nautilus.

If you do not like them:
sudo apt-get purge liboverlay-scrollbar-*

In order to have a tool recognize the changes you have to quit all its instances. Or just log out and back in.

When using gnome-open (i.e. double-clicking a file, telling to browser to open a download, etc.) on Ubuntu you may get this error:

The location is not a folder.

It's due to the exo-utils package which does not play nice with gnome-open. You can fix the problem by uninstalling it:

sudo apt-get remove exo-utils

Note that this may also uninstall XFCE tools like xfce4-terminal or thunar (XFCE's directory browser). If you want to keep them, [try anot...

For Email-Patterns see most recent E-Mail-Pattern.

HOST = /\A[a-z0-9]+[a-z0-9\-\.]*[a-z0-9]+\z/i
BANK_CODE = /\A\d{8}\z/                                          # Germany
BANK_ACCOUNT_NUMBER = /\A\d{1,10}\z/                             # Germany
ZIP_CODE = /\A\d{5}\z/                                           # Germany
HEX_COLOR = /\A([a-fA-F0-9]{3}){1,2}\z/
IP_ADDRESS = /\A(?:25[0-5]|(?:2[0-4]|1\d|[1-9])?\d)(?:\.(?:25[0-5]|(?:2[0-4]|1\d|[1-9])?\d)){3}\z/

We usually put these constants in...

My front audio output would not work even though the front mic input did fine.
The Pulse Audio mixer (= Ubuntu default) does not offer any complex controls to fix the issue. Instead, run gamix (be prepared for a GUI blast) and switch "Independent HP" to OFF. The label may be different for your audio device.

This enables all available audio outputs.

This will install a printer called "PDF":

sudo apt-get install cups-pdf

Files will be put into ~/PDF/ without any questions asked.

You know there is the du command to fetch the disk usage of a directory (“.” in this example). By default, output is sorted by directory name, not size:

du -h --max-depth=1 .
40K  ./a
2.3G ./b
3.1M ./c
500M ./d
2.8G .

To see which directories take up the most (or least) space you can order them by size like this (the -h switch does the magic of understanding humanized size formats):

du -h --max-depth=1 . | sort -h
40K  ./a
3.1M ./c
500M ./d
2.3G ./b
2.8G .

Note that you will need to...

When using the resource_controller gem you often hook onto events like this:
update.before do
do_something
end

For testing such things in your controller you should -- as always -- not trigger something that eventually calls the thing you want.\
Instead, in your specs, have resource_controller run those hooks like it does itself. Like that:

describe 'before update' do
 ...

To check your apache2 config files for syntax errors run

sudo apache2ctl configtest

or shorter

sudo apache2ctl -t

Be aware that this does not guarantee a successful Apache startup. It may still fail due to permission errors, etc.

In order to request a SSL certificate from any dealer, you usually need a CSR certificate. As both the CSR as well as key are created in this step, make sure you save this certificate on a trusted, secure machine only. Usually this is your production environment.

Run this on the server (not on your machine) as root.\
Replace your-domain.tld with the domain you request the certificate for and YYYY with the current year so you will not have any conflicts when requesting a certificate next year.

openssl req -new -sha256 -out www.your-dom...

This snippet makes links that refer to an anchor (like "<a href="#something">...</a>") scroll softly to it.\
In this example we only do it for links that also own a data-animate attribute.

$('a[href^="#"][data-animate]').live('click', function() {
  var hash = $(this).attr('href');
  var offset = $(hash).offset();
  if (offset) {
    $('html, body').animate({ scrollTop: offset.top }, 'slow');
    location.hash = hash;
    return false;
  }
});

Note that this could basically work for any element whos...

If you would like to enrich your website with semantic markup like contact data, places or events you should have a look at schema.org. "Search engines including Bing, Google and Yahoo! rely on this markup to improve the display of search results, making it easier for people to find the right web pages."

The following example from the schema.org documentation shows you how to describe a movie with semantic markup:

<div itemscope itemtype ="http://schema.org/Movie">
  <h1 itemp...

Note: In Rails 3+ you can use Array.wrap instead of the solution here.

In the past you could use Array(...) or #to_a to turn an object into an array, unless it already is an array:

Array(5) # => [5]
Array([5]) # => [5]

Unfortunately this idiom has issues and it also triggers deprecation warnings like this one:

warning: default `to_a' will be obsolete

For an alternative you can copy the attached file to `config/i...

I found a nice script on crazylittlehacks and modified it slightly. Put the attachment to /usr/local/bin, chmod +x and run it like this:

tab

You may also pass a command that will be run in that newly opened tab:

tab ruby script/server

Note: This does not play too nice with Visor, because Visor will always be "window 1" for AppleScript. By modifying the script and replacing in window 1 with `in window...

XPath matchers can be combined with CSS-selector matchers. This is really useful if not, for example, the content of an element should be matched but the element itself like in the following example. Here a form is used to display data as default value in its input elements. This can be the case in web applications in which data should be edited easily without additional clicks.

If you want to enforce soft tabs (spaces instead of tabstops) in Vim put this into your ~/.vimrc (Linux) or C:\Users\<Username>\_vimrc (Windows):

set tabstop=2
set softtabstop=2
set shiftwidth=2
set expandtab

You can also call those commands in a running Vim instance (using ":set ...") to switch on soft tabs temporarily.

On a side note: remember the :mkvimrc command that saves active settings to a vimrc file.

Very nice font for programming.

Copy the attached Ruby code to config/initializers, or paste it into your IRB console. You can now dump any two-dimensional array to an Excel .xls spreadsheet with a single method call:

table = [['user', 'email', 'hours']]
User.all.each do |user|
  table << [user.name, user.email, user.hours]
end

table.dump_to_excel('users.xls')

The first row in the array will be dumped as the table head in bold type.

You need the spreadsheet gem in your Gemfile.

Note that there is a [limit of 65535 rows](https://makandracard...

Update: Staticmatic will not be further developed. They suggest to switch to middleman.

If you need to make a static web page and find yourself missing all your Rails comforts, take a look at StaticMatic.

This works like an extremely stripped down version of Rails, giving you

• HAML
• SASS
• helpers
• partials

When done, everything is simply compiled to s...

Put the attached file into config/initializers/ to be able to say created_within on any ActiveRecord or its scope chain. This will return a scope of all records created between two given timestamps.

Use it like that:
Booking.created_within(1.year.ago, Date.yesterday).count
User.active.created_within(1.hour.ago, DateTime.now)

It explicitly looks at the database table name so you are usually fine when joining other tables.

When running an executable, ALWAYS use bundle exec. In some cases, running executables without bundle exec may work, if the executable happens to be installed in your system and does not pull in any gems that conflict with your bundle. However, this is unreliable and is the source of considerable pain. Even if it looks like it works, it may not work in the future or on another machine.