At makandra, we've built a few gems over the years. Some of these are quite popular: spreewald (> 1M downloads), active_type (> 1M downloads), and geordi (> 200k downloads)

Developing a Ruby gem is different from developing Rails applications, w...

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?...

While it might seem trivial to implement an invoice that sums up items and shows net, gross and vat totals, it actually involves a lot of rules and caveats. It is very easy to create invoices where numbers don't add up and a few cents are missing....

To update your Rubygems to the latest available version, type the following:

 gem update --system

Note that you have a separate Rubygems installation for each Ruby version in your RVM or rbenv setup. Updating one does not update the others.
...

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...

Rbenv won't compile REE 2011.03 properly on Ubuntu 12.04, failing with an error in tcmalloc.cc.

If you want to keep tcmalloc functionality, you can do it like this:

1. Open ~/.rbenv/plugins/ruby-build/share/ruby-build/ree-1.8.7-2011.03
2. Re...

On recent/fresh installations of Ruby 1.8.7 you may encounter this error why calling any bundled binary (or just bundle exec):

/home/arne/.rvm/gems/ruby-1.8.7-p374@global/gems/rubygems-bundler-1.4.2/lib/rubygems-bundler/noexec.rb:75:in ...

Sometimes you want one distinct version of RubyGems to be installed to replicate the same behavior across multiple servers.

Usually would do this to update your RubyGems, but this always takes you to the latest version:

gem update --system

...

For my computer science bachelor's thesis I programmed and evaluated a CLI Test Case Prioritization (TCP) tool for makandra. It has been written as a Ruby Gem and was tested and evaluated against one Ruby on Rails project....