Heads up: "localhost" may be IPv6 on new linuxes

The linked article points out that COUNT queries might be unexpectedly slow in PostgreSQL.

If you just need to know "are there any records" use any?. This uses SELECT 1 AS one FROM ... LIMIT 1 under the hood.
If you just need to know "...

RSpec provides a nice diff when certain matchers fail.

Here is an example where this diff is helpful while comparing two hashes:

{a:1}.should match(a:1, b:2)

Failure/Error: {a:1}.should match(a:1, b:2)
  expected {:a=>1} to match {:a=>1, :b...

With cd .. you can navigate one directory up from the one you are at now. If you use that a lot, consider some handy aliases.

Add the following lines to your ~/.bashrc:

alias ..="cd .."
alias ...="cd ../.."
alias ....="cd ../../.."
alias ...

Angular's location provider stalls links to the current URL, i.e. window.location. As soon as the $location service is activated in an Angular app, it will intercept links. The click event handler is registered in $LocationProvider.$get().

The...

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.

By convention, common protocols use a defined port, like 80 for HTTP or 443 for HTTPS.

You can use nmap to find out what service is running behind a given port, and most often see some details about it. This can be helpful if servers don't offe...

jQuery has a function $.fn.trigger(). You can use it to dispatch an event on a jQuery object:

let $element = $('.foo')
$element.trigger('change')

A caveat is that such an event will be received by jQuery event listeners, but ...

will_paginate triggers a database query to determine the total number of entries (i.e. to let you display the number of search results). When you paginate complex scope (e.g. that has many includes),...

We had a card that described how to install multiple mysql versions using mysql-sandbox. Nowadays with the wide adoption of docker it might be easier to u...

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