I was annoyed that RubyMine's autocompletion did not work via Ctrl+Space for me. In fact, it did not work in any application.

Turns out that keyboard combination was hijacked by Ubuntu as it's the default for switching input languages (i.e. keyboard layouts). If you use only 1 language/layout, you will not notice except for the key not working.

To fix it, do the following:

1. Run ibus-setup (e.g. from a terminal). This will open a GUI dialog.
2. In the 1st tab you should see "Next Input Method" followed by "<Control>space".
3. Click t...

After adding a vdisk to an ESXi linux guest you will assert that you can't find a new device in the running VM. You have to force a SCSI rescan.

1. find your host bus number with: grep mtpspi /sys/class/scsi_host/host?/proc_name
2. output should look like this: /sys/class/scsi_host/host2/proc_name:mptspi where the bold part is what you're searching for
3. force an SCSI rescan with echo "- - -" > /sys/class/scsi_host/<host>/scan and insert the host found in point two for <host>
4. cat /proc/scsi/scsi should now show the new ad...

If you're a frequent user of LibreOffice, I strongly recommend to checkout out the VLOOKUP function (SVERWEIS in German). It allows you to treat a column pair as a hash map, where you lookup keys in the first column and return values from the second.

Small (1.5 KB) Javascript library that lets you render tables, lists, etc. with hundreds of thousands of items.

How it works is that you move your data set from the DOM into JS. Clusterize than makes sure only the rows in the viewport (and adjacent batches) are rendered.

I believe that AngularUI's data grid component uses a similar technique to reduce the number of bindings in large tables, but I can't seem to find documentation on that.

Jasmine has a jasmine.clock() helper that you can use to travel through time and trigger setTimeout and setInterval callbacks:

beforeEach(function() {
  timerCallback = jasmine.createSpy("timerCallback");
  jasmine.clock().install();
});

afterEach(function() {
  jasmine.clock().uninstall();
});

it("causes a timeout to be called", function() {
  setTimeout(function() {
    timerCallback();
  }, 100);

  expect(timerCallba...

You might wonder about this request in your test.log:

Started GET "/__identify__" for 127.0.0.1 at 2015-04-29 18:00:02 +0100

This is what happens: For drivers like Selenium, Capybara will boot up a Thin or Webrick server in a separate thread. It then makes a GET request to /__identify__ to see if the server is ready to accept requests.

Since you don't have a route that responds to /__identify, Capybara will wrap your Rails app in...

If you need a gem for a certain purpose, be sure to check this site.

The rankings are determined by counting up the number of forks and watchers of various github projects, so I'd view it less as "this is what I should be using," and more as "these are some things I should check out." At the very least, they're all likely to be under active development and fairly up to date, and it's very useful to see groups of gems broken down by category.

Service that you can integrate for user feedback.

Super-simple integration: Add a <script> tag to your layout, done.

It will then add a button to the bottom right of your application. When a user clicks it, they can take a screenshot and leave a message. The screenshot then appears in TrackDuck's interface for you to work off.

Current pricing is 9 USD per month for the smallest tier (1 project).

jquery-placeholder is a simple jQuery plugin that enables form placeholders in browsers that do not support them natively, i.e. IE < 10.

Properties

• Works in IE6.
• Automatically checks whether the browser natively supports the HTML5 placeholder attribute for input and textarea elements. If this is the case, the plugin won’t do anything. If @placeholder is only supported for input elements, the plugin will leave those alone and apply to textareas exclusively. (This is the case for Safari 4, Opera 11.00, and possibly other browsers.)
  ...

TL;DR Under certain circumstances, dynamically defined symbols may break keyword arguments in Ruby 2.2. This was fixed in Ruby 2.2.3 and 2.3.

Specifically, when …

• there is a method with several keyword arguments and a double-splat argument (e.g. def m(foo: 'bar, option: 'will be lost', **further_options))
• there is a dynamically created Symbol (e.g. 'culprit'.to_sym) that is created before the method is parsed
• the method gets called with both the option and a culprit keyword argument

… then the `optio...

dmesg shows the kernel ring buffer containing low-level system messages.
Per default, dmesg shows a timestamp:

12:59:26 fnordomator ~ > dmesg | tail
[101925.211846] usb 2-1.1: USB disconnect, device number 16
[110486.855788] usb 2-1.1: new high-speed USB device number 17 using ehci_hcd

If you're a human, use dmesg -T to print the timestamp human readable:

12:59:31 fnordomator ~ > dmesg -T | tail
[Di Apr 21 12:43:16 2015] usb 2-1.1: USB disconnect, device number 16
[Di Apr 21 15:05:57 2015] usb 2-1.1: new hig...

When using send_file (for example for attachments of any kind), make sure your application knows the correct mime types so that all browsers can handle the files. It is much more convenient for users if they can decide to open a file directly instead of having to save it first.

For Rails >= 3.2

Simply put your mime types in config/initializers/mime_types.rb. send_file will take care of everything else.

For Rails < 3.2

Put your mime types in config/initializers/mime_types.rb. Additionally, tell send_file to use them (for ex...

You can freeze any Ruby object to prevent further modification.

If you freeze an ActiveRecord and try to set an attribute you will an error like this:

can't modify frozen hash

This is because ActiveRecord delegates #freeze to its attributes hash.

You can unfreeze most Ruby objects by creating a shallow copy of the frozen object by calling #dup on it:

user = User.find(3)
user.freeze
unfrozen_user = user.dup

Notes for Rails 2 users
-----------------...

Rails comes with a Rake task notes that shows code comments that start with "TODO", "FIXME", or "OPTIMIZE".

While it's generally not good practice to leave them in your code (your work is not done until it's done), in larger projects you will occasionally have to use them as other parts of the application that you depend upon are not yet available.
To keep track of them, run rake notes. Its output looks something like this:

$ rake notes
app/controllers/fron...

If you want to grow a Ruby Array, you might find out about #fill but it is not really what you are looking for. [1]
For arrays of unknown size that you want to grow or shrink to a fixed size, you need to define something yourself. Like the following.

Array.class_eval do

  def in_size(expected_size, fill_with = nil)
    sized = self[0, expected_size]
    sized << fill_with while sized.size < expected_size
    sized
  end

end

Use it like this:

>> [1, 2, 3].in_size(5)
=> [1, 2, 3, nil, nil]

...

Code folding is a very useful feature to me. It gives me a quick overview over a file and keeps me from scolling like a hamster in its wheel.

Keyboard shortcuts:

Collapse/expand current code block

strg -/+

Collapse/expand the whole file

strg ctrl -/+

When diving into Cucumber features or huge Ruby classes, I usually collapse all and the gradually expand what I need.

To use a form model with devise, you can simply override #resource_class in a controller. A typical use case would be the registrations controller, as users will need some fields only on sign-up. Example:

class Frontend::Authentication::RegistrationsController < Devise::RegistrationsController

  private

  def resource_class
    FrontendUser::AsSignUp # my decorator class, extending from FrontendUser
  end

end

List of cloud services and SaaS with a free tier for developers or that are generally free for open source software.

Fontawesome 4 ships with many useful CSS helper classes.

Enlarge Icon

Add fa-lg (133%), fa-2x, fa-3x, fa-4x or fa-5x.

Fixed-width Icon

Add fa-fw. Will give all icons the same width.

Styling Lists

Add fa-ul to a <UL> and fa fa-<icon name> fa-li to a <LI> to give the list items custom "bullets".

Bordered Icon

Add fa-border to get a border around the icon.

Spinning Icon

Add fa-spin to make any icon rotate. Suggested icons: fa-spinner, fa-refresh, fa-cog. Doesn't work in IE <10.

Ro...

Fontawesome 4 has introduced new naming conventions that make it easy to retrieve variants of a given icon.

The format is:

fa-[name]-[alt]-[shape]-[o]-[direction]

Note that this is a naming convention which doesn't imply there's an icon for any combination of tags.

name

The name of the icon, e.g. comment, print, bookmark etc. See the full list.

alt

An alternative icon.

shape

The icon inside a circle or square.

o

An outlined ...

There are some frontends available, but they all suck, are no longer maintained or are hard to install.

As a surprisingly comfortable alternative I have found a command line tool s3cmd:

sudo apt-get install s3cmd

When you run s3cmd the first time it will ask you for your access key ID and secret access key. This information is cached somewhere so you only need to write them once. To reconfigure later, call s3cmd --configure.

Once you're done setting up, s3cmd gives you shell-like commands like s3cmd ls or `s3cmd del som...

• Now supports RSpec 3 and Rails 4
• Drops support for state_machine, which has some issues with Rails 4 and isn't actively maintained

Awesome hack by Tim VanFosson:

<img src="some.jpg" onerror="this.src='alternative.jpg'" />