You login to a Linux server with a performance issue: what do you check in the first minute? uptime

rack-mini-profiler is a powerful Swiss army knife for Rack app performance. Measure SQL queries, memory allocation and CPU...

In Ruby 2.3 you can use <<~ instead of <<- to automatically remove indentation from a HEREDOCs: str = <<~MESSAGE Hello Universe!

The nokogiri gem provides different packages for several platforms. Each platform-specific variant ships pre-built binaries of libxml2, e.g...

E-mails are usually encoded using Quoted Printable. Here is how to decode or encode such strings. You probably know...

When using Sidekiq in your application, you must write thread-safe code. This wiki page also lists gems that are...

This looks like it is safe to use: 2.2.1 :001 > a = b = "hello world" "hello world" 2.2.1 :002 > a

There are different ways to define a lambda or proc in ruby. [*] with lambda keyword test = lambda do |arg|

This class contains nerdcore things such as disassembling a piece of Ruby into VM calls or enabling tail-call optimization...

Sometimes you just want to have a small web server that serves files to test something. Serve the current directory...

There are many solutions, but a very concise one is this: hash.merge!(hash) do |key, old_value, new_value|

Sometimes you want to know exactly how many objects exist within your running Ruby process. Here is how: stats = {} ObjectSpace.each...

This is basically Ruby-native syntax for andand.

Ruby has a set of methods to convert an object to another representation. Most of them come in explicit and...

When you make a simple TCP connection to a remote server (like telnet), your client won't normally notice when...

You want to test your 1GE or 10GE internet uplink? We needed to ensure we have full 10GE to the...

Ruby allows multiple assignment: a, b, c = o In order to prove multiple values from a single object, Ruby calls...

When a method has keyword arguments, Ruby offers implicit conversion of a Hash argument into keyword arguments. This conversion is...

Writing ruby methods that accept both optional and keyword arguments is dangerous and should be avoided. This confusing behavior will...

Starting with Rails 4.0, when you get an exception reported via the ExceptionNotification gem, you will only see a very...

Starting with Ruby 1.9, most #each methods can be called without a block, and will return an enumerator. This is...

To safely transport an arbitrary string within a URL, you need to percent-encode characters that have a particular meaning...

While debugging an intricate issue with failed HTTP requests I have come to appreciate the more advanced features of the...