Bundler: How to install version 1 instead of 2 (latest version)
When installing a gem you can use version comparators like >= or ~>. That way it is possible to fetch the latest version of Bundler 1 with this command:
gem install bundler -v '~>1'
How to install bundler for Ruby < 2.3 is a common usecase where you might need Bundler 1.
Related cards:
How to view Image Metadata on the Linux Command Line with ImageMagick
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+...
DNS debug tools
There are several tools for DNS debugging which offer you more or less information. Most of the time the more simple ones, like host oder nslookup will be sufficient.
host
simple DNS lookup utility.
>host heise.de
heise.de has addr...
Upgrading Rails 2 from 2.3.8 through 2.3.18 to Rails LTS
This card shows how to upgrade a Rails 2 application from Rails 2.3.8 through every single patch level up to 2.3.18, and then, hopefully, Rails LTS.
2.3.8 to 2.3.9
This release has [many minor changes and fi...
How to make Rational#to_s return strings without denominator 1 again
The way Rational#to_s works on Ruby has changed from Ruby 1.9 on. Here is how to get the old behavior back.
You may want this for things where Rationals are being used, like when subtracting Date objects from one another.
What's happening?...
How to create memory leaks in jQuery
jQuery doesn't store information about event listeners and data values with the element itself. This information is instead stored in a global, internal jQuery cache object. Every time you add an event listener or data value to a jQuery object, ...
Installing Ruby 2.3 or below on Ubuntu 17 and above
From Ubuntu 17, rbenv fails to install Ruby below 2.4 because of a mismatching OpenSSL dependency: it needs libssl1.0-dev for the installation process, but recent Ubuntus come with libssl-dev.
From the linked StackOverflow comment:
As fa...
Video transcoding: Web and native playback overview (April 2020)
Intro
Embedding videos on a website is very easy, add a <video> tag to your source code and it just works. Most of the time.
The thing is: Both the **operating system and Browser of your client must support the container ...
JavaScript without jQuery (presentation from 2019-01-21)
Summary
- We want to move away from jQuery in future projects
- Motivations are performance, bundle size and general trends for the web platform.
- The native DOM API is much nicer than it used to be, and we can polyfill the missing pieces
- Un...
How to install packages from newer Ubuntu releases
We're usually running Ubuntu LTS versions. Sometimes newer hardware requires packages from more recent Ubuntu releases that only come with 6 months of support. If there is really no other way, it's possible to install packages from later Ubuntu re...
Upgrading Cucumber and Capybara to the latest versions available for Rails 2
Specify these gem versions in your Gemfile:
gem 'cucumber', '~> 1.3.0'
gem 'cucumber-rails', '= 0.3.2' # max version for Rails 2
gem 'capybara', '< 2' # capybara 2+ requires Rails 3
gem 'mime-types', '< 2' # dependeny of capybara
...