Here is a hacky way to load dumps directly from the source server, without fully copying them over and extracting them first.

It may break horribly for you. This is the dark side of the force.

1. Install pipe viewer, if you don't have it already: sudo apt-get install pv
2. Know the location of the dump file on the remote server. We'll use /mnt/dumps/my_project.dump.bz2 in the example below.
3. Find out the size of the (bzipped) file in by...

Given you use Capistrano together with bundler to automatically install your gems when deploying.

I recently had the problem that Capistrano stalled like this:

[err :: host.name.tld] Username:

It turned out that I this originated from GitHub. We had a gem in our Gemfile that explicitly pointed to a GitHub URL like that:

gem 'foogem', :git => 'https://github.com/blubb/foogem.git'

The URL was returning a 404 which caused the problems. You have to get another gem or point to a fork on GitHub.

Good collection of crash-course articles about founding a start up, getting funded, validating ideas, etc.

Safari & Chrome

Use $x() in your console:

$x('//span') # selects all span elements

Firefox

There's an add-on.

So you want to know if you are on natty, precise, quantal, or something else? Check /etc/lsb-release.

$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=12.04
DISTRIB_CODENAME=precise
DISTRIB_DESCRIPTION="Ubuntu 12.04.2 LTS"

Or, use the lsb_release command:

$ lsb_release -cd
Description:	Ubuntu 14.04.1 LTS
Codename:	trusty

You might get the following error:

Unable to initialize.
Make sure the daemon is running.
Error: Process /usr/lib/sflphone/sflphoned exited with status 1

This mean the last process didn't shut down properly and let a PID file lie around. You can delete it with

rm ~/.cache/sflphone/sfl.pid

(If you've shut sflphone down some seconds ago, you just have to wait 10 seconds and don't have to remove the pid file manually)

Mozilla has announced that, starting with Firefox 22, the popular open source web browser will begin blocking third-party cookies by default. That means only websites you actually visit will be allowed to set cookies; advertisers on those sites will no longer be able to easily track you by setting a cookie.

MongoMapper is a MongoDB adapter for Ruby. We've forked it so it works for Rails 2.3.x applications running on Ruby 1.9. [1]

makandra/mongomapper is based on the "official" rails2 branch [2] which contains commits that were added after 0.8.6 was released. Tests are fully passing on our fork for Ruby 1.8.7, REE, and Ruby 1.9.3.

To use it, add this to your Gemfile:

gem 'mongo_mapper', :git => 'git://github.com/makandra/mongomapper.git', :branch => 'rails2'

...

Ruby 1.9 changed the default behavior of Module.const_defined? from what it was in Ruby 1.8 -- this can be especially painful when external code (read: gems) uses const_defined? to look something up and gets different results on different Rubies.

Consider this:

module Foo
  FOO = 42
end

class Bar
  include Foo
end

On Ruby 1.8, Bar won't have FOO defined as a constant since that's (even though it's accessible):

1.8.7 > Foo.const_defined? :F...

See attached link for a way to extract the conditions of a named scope in Rails 2.3.

This error can happen in Ruby 1.9.

To fix it, add the following line to the top of your .js.erb file:

<%# @encoding: UTF-8 %>

Rails 2.3.16+ on Ruby 1.9 causes warnings like this:

.../gems/activesupport-2.3.17/lib/active_support/core_ext/string/output_safety.rb:22: warning: regexp match /.../n against to UTF-8 string

Many thanks to grosser for supplying a monkey-patch for Rails 2.3 (Commit f93e3f0ec3 fixed it for Rails 3). Just put it into config/initializers/ to make those warnings go away.

Since we're using RSpec on mos...

Prepare to explain customers what changed if your application renders PDF documents to users.

So you have a method returning a regular expression but one case that should not yield a matching Regexp object but still keep the API stable? Just return one that never matches:

/(?!)/

If you need to capture signatures on an IPad or similar device, you can use Thomas J Bradley's excellent Signature Pad plugin for jQuery.

To implement, just follow the steps on the Github page.

The form

If you have a model Signature with name: string, signature: text, you can use it with regular rails form like this:

- form_for @signature, :html => { :class => 'signature_form' } do |form|
  %dl
    %dt
      = form...

If others on a call (Skype, SIP, ...) can not hear you loud enough, your volume levels are probably too low. Also, Skype may be changing your mixer levels.

Set a proper recording volume

1. Open your mixer software (run pavucontrol).
2. Switch to input devices.
3. If you have more than one recording device, find the correct one.
4. Make a test call to a colleague that can tell you if it's too loud or too quiet.
5. Drag the volume slider for your input device to an adequate level -- for me, 75% (-7.46dB) work fine. 100% is usually way to...

So you're using multiple remotes that offer the same branch?

$ git branch -a | grep my-branch
  remotes/something/my-branch
  remotes/origin/my-branch

And when trying to check out that remote branch, it fails for you with an error like this?

$ git checkout my-branch
error: pathspec 'my-branch' did not match any file(s) known to git.

Git usually guesses the remote branch to check out, but when using more than one remote, it seems like it no longer can do that.
Even if the branch is the same on both remotes, you nee...

You either have an old version of Mocha and an edge version of Rails 3.2, or you have a new version of Mocha and an old version of Rails. The best solution is to update Mocha to the latest version and switch to Rails edge.

If you are using shoulda-matchers or another gem that locks Mocha to an old version, you are out of luck.
More info with many other workarounds that you do not want to use can be found here. A hack to work around this case is to add the following file to lib/mocha/setup.rb:...

Counters are an awesome CSS feature you didn't know about. It is supported in all browsers and IE8+.

CSS counters are an implementation of Automatic counters and numbering in CSS 2.1. The value of a counter is manipulated through the use of counter-reset and counter-increment and is displayed on a page using the counter() or counters() function of the content property.

Stringex is a gem that offers some extensions to Ruby's String class. Ruby 1.9 compatible, and knows its way around unicode and fancy characters.

Examples for stringex's String#to_url method:

# A simple prelude
"simple English".to_url => "simple-english"
"it's nothing at all".to_url => "its-nothing-at-all"
"rock & roll".to_url => "rock-and-roll"

# Let's show off
"$12 worth of Ruby power".to_url => "12-dollars-worth-of-ruby-power"
"10% off if you act now".to_url => "10-percent-off-if-you-act-now"

# You do...

UnicodeUtils implements Unicode algorithms for case conversion, normalization, text segmentation and more in pure Ruby code.

If you don't need the ton of features that UnicodeUtils offers, try stringex.

RVM needs to be updated regularly to know of Ruby versions released since installation (or last update).

So if you say rvm install 1.9.3, but get an old version (basically anything below 1.9.3-p385 when writing this card), your RVM is outdated. \
Fix that by saying:

rvm get stable

After that, rvm install 1.9.3 should install the latest 1.9.3 version.

If bundle install shows the following message for you ...

Error Bundler::HTTPError during request to dependency API

... upgrade to Bundler ≥ 1.2.4:

gem install bundler

Apparently, it just hides the message.

In our continued quest to extract proven code snippets from makandropedia into tested and upgradable gems, we have released Edge Rider.

Edge Rider was created with two intents:

1. Provides a number of utility methods to facilitate hardcore work with scopes.
2. Provide a stable API for working with scopes across multiple versions of Rails, since Rails has a tradition of breaking details of its scope API every other release.

The gem bundles multiple patches and initializers we've been using for hard...