Luckily, this is simple. Just install three packages:

sudo apt install ipheth-utils libimobiledevice-dev libimobiledevice-utils

Then turn on the "Personal Hotspot" in iPhone settings, connect it to your Ubuntu machine via USB and you should be up and running.

Imagine the following HTML structure, where the scrolling container has overflow-y: scroll:

+--scrolling container+-+
|                       |
| +-child element+----+ |
| | ++iframe++        | |
| | |        |        | |
| | |        |        | |
+-----------------------+
  | |        |        |   <-- actually cut off by
  | +--------+        |   <-- scrolling container
  +-------------------+

The issue: On iOS, the child element cannot be scrolled when grabbing the iframe (i.e. putting your finger somewhere on the iframe).
...

When you load a dump for development, records may reference images that are not available on your machine.

Requests to those images may end up on your application, e.g. if a catch-all route is defined that leads to a controller doing some heavy lifting. On pages with lots of missing images, this slows down development response times.

You can fix that by defining a Rails route like this:

if Rails.env.development?
  scope format: true, constraints: { format: /jpg|png|gif/ } do
    get '/*anything', to: proc { [404, {}, ['']] }

...

Small web application where you can upload an image (PNG, JPEG, GIF) and generate a base64-encoded version of it.

You can copy the result as

• HTML <img> tag with data URI,
• CSS rule with background-image and data URI,
• plain Base64-encoded data URI string.

Sometimes you want/have to send specific http(s) requests. You can do that easy with curl or just write the request yourself.

make a http request with nc

nc example.com 80
GET / HTTP/1.1
Host: example.com
# press enter

make a http request with telnet

telnet example.com 80
GET / HTTP/1.1
Host: example.com
# press enter

make https request with openssl

openssl s_client -connect example.com:443
GET / HTTP/1.1
Host: example.com
# press enter

You can specify more headers if you want:

nc example.c...

For the initial setup or changes in the sentry reporting it might be useful to enabled reporting of sentry in development. Don't commit these changes and prefer to report to the staging environment. As other developers might be confused of these errors try to given them a proper message and delete them afterwards.

1. Add config.raven_dsn = 'your-dns' in config/environments/development.rb.
2. Add development to existing environments in the Raven.configure block: config.environments = ['development', 'staging', 'production'].
3. ...

ImageMagick has a command line tool called identify which can read image metadata:

>identify -verbose DSC00136.JPG
Image: DSC00136.JPG
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Class: DirectClass
  Geometry: 5472x3648+0+0
  Resolution: 350x350
  Print size: 15.6343x10.4229
  Units: PixelsPerInch
  Type: TrueColor
  Endianess: Undefined
  Colorspace: sRGB
  Depth: 8-bit
  Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
  Channel statistics:
    Red:
      min: 0 (0)
      max: 255 (1)
      mean: 11...

iOS Safari tries to be helpful and enlarges some(!) texts when you turn to landscape mode. In precise CSS building, this is annoying. Disable this behavior with:

body
  -webkit-text-size-adjust: 100% // Prevent font scaling in iOS landscape

You can start vim with a read-only option. This prevents making accidentally changes in files you don't want to touch.

view /file/to/open

view is actually vim.

Use case

You have opened many similar files and accidentally type :wq in the wrong one. Did you make changes? Which changes you made? When do you notice you edited the wrong file?

Barby is a great Ruby gem to generate barcodes of all different sorts.

It includes support for QR codes via rQRCode; if you need to render only QR codes, you may want to use that directly.

Example usage

Generating a barcode is simple:

>> Barby::Code128.new('Hello Universe').to_png
=> "\x89PNG\r\n\u001A..."

Configuration

Barby supports several barcode types and you must require all necessary files explicitly.

For the example a...

git command line options for automating common rebasing tasks, like adding a fix to a commit that was already rebased into the history.

The maximum version of Internet Explorer you can have depends on your version of Windows. E.g. Windows 7 users can use Internet Explorer up to version 11, but they cannot upgrade to Edge.

Since early 2016, Microsoft only supports the latest version of IE that is available for a given version of Windows. If you are using an older version of IE than you could, you will no longer receive security patches for your version.

In April 2017, this means the following:

• Intern...

This is a visualization of the files that will be generated by some useful rails generators. Invoke a generator from command line via rails generate GENERATOR [args] [options]. List all generators (including rails generators) with rails g -h.

To move elements around we should be familiar with coordinates. Most JavaScript methods deal with one of two coordinate systems:

• Relative to the window(or another viewport) top/left.
• Relative to the document top/left.
  It’s important to understand the difference and which type is where.

Just dumping this in case somebody might need it.

When you need a CSS value (a padding, margin, height etc) to shrink/grow proportionally with the parent element, you normally use percentage values. However, if you need specific values at two given widths, you need to turn to linear functions. The mixin below gives you just that.

// Call with two desired values at two different widths.
// Returns a calc() expression that will scale proportionally between those two.
// Example:
//   Spaci...

Crontabs are often unordered, especially when generated for an application where you usually group tasks by their domain/scope.

An example crontab might look like this:

# Begin Whenever generated tasks for: project100
MAILTO="log@example.com"
MAILFROM="cron@example.com"

# When server is booting up, ensure Sidekiq is running
@reboot start_sidekiq

23 8 * * * baz
30 * * * * plop
5 8 * * * bar
1 0 * * * foo
# End Whenever generated tasks for: project100

While you can human-parse this one easily, crontabs with several lines are hard ...

Looks like ActiveState is trying to market a new Ruby distribution for Enterprises:

ActiveRuby Enterprise Edition is designed for businesses with large Ruby deployments in essential, mission-critical applications that, when down, could cost your business in lost revenue and a damaged reputation. Deploy Ruby with confidence knowing you're using the most secure, enterprise-grade builds for the platforms that power your business. You'll get priority access to our Ruby experts for technical support and best prac...

The postMessage API is an alternative to JSONP, XHR with CORS headers and other methods enabling sending data between origins. It was introduced with HTML5 and like many other cross-document features it can be a source of client-side vulnerabilities.

Using VCR to record communication with remote APIs is a great way to stub requests in tests. However, you may still want to look at the request data like the payload your application sent.

Using WebMock, this is simple: Make your request (which will record/play a VCR cassette), then ask WebMock about it:

expect(WebMock).to have_requested(:post, 'http://example.com').with(body: 'yolo')

Easy peasy.

Related cards

• Faking and testing the network with WebMock

Using the dialog command you can launch ASCII-art dialogs from your shell scripts.

Check out man dialog for a list of supported dialog types. Aside from simple text boxes or choice dialogs, it supports more advanced interactions like file pickers or progress bars.

Example: Yes/no choice

dialog --yesno "Erase the world?" 0 0

Example: Menu with multiple opt...

Add the following to /etc/rc.local:

(sleep 3 && echo disable > /proc/acpi/ibm/bluetooth)&

Bluetooth icon will be active for a few seconds, then turn gray.