Ubuntu lets you mount an SSH shell into Nautilus from Places -> Connect to server (select "SSH" as server type).

In order to copy a file over SSH from a shell:

scp filename username@remotehost:

The trailing ":" directs the file to username's home directory on the remote host.

You can also copy a file from the remote host to your local machine:

scp remotehost:remotepath localpath

In my case [...] the catalog is an XML that contains all kinds of possible products, categories and vendors and it is updated once a month. When you read this file with the Nokogiri default (DOM) parser, it creates a tree structure with all branches and leaves. It allows you to easily navigate through it via css/xpath selectors.

The only problem is that if you read the whole file into memory, it takes a significant amount of RAM. It is really ineffective to pay for a server if you need this RAM once a month. Since I don't need to n...

Starting from Rails 4.0, you can use a special form options helper called #collection_check_boxes. It behaves similar to #collection_select, but instead of a single select field it renders a checkbox and a label for each item in the collection.

= form_for @post do |form|
  = form.collection_check_boxes :author_ids, Author.all, :id, :name_with_initial

How generated form params look like
---------------------------------...

Was ist Elastic?

• Suchmaschine, basierend auf Apache Lucene
• größtenteils Open-Source
• einige kommerzielle Features ("Elastic Stack", früher "X-Pack")
  • Zugriffsrechte (bis vor kurzen)
  • Monitoring
  • Reporting
  • Graph-Unterstützung
  • Machine Learning
• REST-Api (JSON über HTTP)

Grundlagen

Elastic antwortet per Default auf Port 9200

http GET :9200

{
  "name": "ntK2ZrY",
  "cluster_name": "elasticsearch",
  "cluster_uuid": "Bbc-ix5bQZij5vfFU29-Cw",
  "version": {
    "number": "6.7.1",
    "build_flavor": "...

I've got often this error on just one server:

Err http://de.archive.ubuntu.com precise/universe amd64 Packages
404  Not Found [IP: 141.30.13.20 80]

But there was no problem with the network connection or the de.archive.ubuntu.com server.

After I deleted the local lists cache with rm -r /var/lib/apt/lists it works again.

Turbolinks makes following links in your web application faster. Instead of letting the browser recompile the JavaScript and CSS between each page change, it keeps the current page instance alive and replaces only the body and the title in the head.

This is similar to pjax, but instead of worrying about what element on the page to replace, and tailoring the server-side response to fit, we replace the entire body. This means that you get the bulk of the speed benefits from pjax (no recompiling of the JavaScript or CSS) without having to tail...

6.0.0 2021-06-02

Compatible changes

• geordi commit will continue even if one of the given projects is inaccessible. It will only fail if no stories could be found at all.

Breaking changes

• Removed VNC test browser support for integration tests – Headless Chrome has
  matured and is almost a drop-in replacement. Also, key binding issues have
  increased with VNC and recent Linux.
  • Please use a headless Chrome setup https://makandracards.com/makandra/492109-capybara-running-tests-with-headless-chrome.
  • You might also ...

So you client has asked you to implement a row of buttons to like the URL on Facebook, Twitter and Google+. Here are some things you should know about this.

0. Security considerations

Each "like" button is implemented by including a Javascript on your site. This means you are running fucking remote code on your page. You are giving Facebook, Twitter and Google+ full permission to e. g. copy user cookies. Check with your client if she is cool with that. Also note that if you're site is suggesting security by operating under HTTPS ...

This is how you regain disk space from OpenStack instances if you are using kvm and qcow.

If your instance used up all configured disk space once the disk file remains big. You can end up in a situation where for example the instance use only 20GB disk space but the disk file on the server has 100GB (or even more).

To resize the disk file do the following:

1. Check storage on the instance:

   vm $ df -h
   Filesystem      Size  Used Avail Use% Mounted on
   /dev/vda1        99G   19G   75G  21% /
   udev            2.0G   12K  2.0...
   

Using CSS sprites for background images is a technique for optimizing page load time by combining smaller images into a larger image sprite.

There are ongoing arguments on how useful this still is, as modern browsers become more comfortable to load images in parallel. However, many major websites still use them, for example amazon, [facebook](...

When searching for text in a MySQL table, you have two choices:

• The LIKE operator
• FULLTEXT indexes (which currently only work on MyISAM tables, but will one day work on InnoDB tables. The workaround right now is to extract your search text to a separate MyISAM table, so your main table can remain InnoDB.)

I always wondered how those two methods would scale as the number of records incr...

When we want to use our own (or bought) fonts in an application with Webpack(er), we have two options. We can

• put the fonts directly into your Webpack's assets folder or
• write an npm package with an own sass file that can be imported from the Webpack manifest.

Load fonts from your assets folder

The first option turns out to be straightforward: Import the stylesheets in the index.js of the pack you're using:

// webpack_source_path/application/index.js

import './stylesheets/reset'
import...

To show the MySQL default character set you have to login to the MySQL console and execute SHOW VARIABLES LIKE 'char%';

mysql> SHOW VARIABLES LIKE  'char%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | latin1                     |
| character_set_connection | latin1                     |
| character_set_database   | latin1                     |
| chara...

The technique described in this card has an important caveat: The result of GROUP_CONCAT is truncated to the maximum length that is given by the group_concat_max_len system variable, which has a default value of 1024. This will cause horrible, data-destroying bugs in production. For this reason you should probably not use GROUP_CONCAT ever. At least you must set the value of group_concat_max_len to an insanely high value on every database server your application runs on.

Lik...

If you need to capture signatures on an IPad or similar device, you can use Thomas J Bradley's excellent Signature Pad plugin for jQuery.

To implement, just follow the steps on the Github page.

The form

If you have a model Signature with name: string, signature: text, you can use it with regular rails form like this:

- form_for @signature, :html => { :class => 'signature_form' } do |form|
  %dl
    %dt
      = form...

So you're getting this failure when running bundle install on an older project:

Your Gemfile.lock is corrupt. The following gems are missing from the DEPENDENCIES section: 'archive-tar-minitar' 'hoe' 'rcov'

This happens when you are using a new version of Bundler with a project that was bundled with a very old version of Bundler. For reasons unknown, the Bundler dependency API returns different dependencies for some gems (like ruby-debug or rainpress) than the dependencies found in the downloaded gemspecs. While old versi...

RawGit serves raw files directly from GitHub with proper Content-Type headers, for CDN-like purposes.

Note that they don't offer any uptime guarantee. You probably don't want to use it in production, but it may serve you well for some testing/prototyping/etc.

To upload a file via AJAX (e.g. from an <input type='file'>) you need to wrap your params in a FormData object.

You can initialize a FormData using the contents of a form:

var form = document.querySelector('form.my-form') // Find the <form> element
var formData = new FormData(form); // Wrap form contents

Or you can construct it manually, param by param:

var fileInput = document.querySelector('form input[type=file]');
var attachment = fileInput.files[0];

var f...

We recently decided to put static content for HouseTrip.com to Amazon Cloudfront for a faster user experience. This happens fully automatically on deploy and is transparent in development. Together with a heavy use of sprites this sped up page load time quite nicely.

These are a couple of the problems you need to solve in order to do this:

• There is no good way to invalidate Cloudfront cached assets, and Cloudfront will ignor...

The Ace editor is a great enhancement when you want users to supply some kind of code (HTML, JavaScript, Ruby, etc).
It offers syntax highlighting and some neat features like auto-indenting.

For Webpack 3+

Integrate as described in the documentation. For example load ace Editor like this:

  function loadAceEditor() {
    return import(/* webpackChunkName: "ace" */ 'ace-builds/src-noconflict/ace').then(() => {
      return import(/* webpackChunkName: "ace" */ 'ace-builds/webpack-r...

In case you have sensitive data within your RDS instance, you want to use encrypted connections between your application and RDS instances. If you're using MySQL on RDS, here's what to do:

1. Download the AWS CA file and copy it to the machine you want to connect from: http://s3.amazonaws.com/rds-downloads/mysql-ssl-ca-cert.pem
   As far as I could find out, you (currently) cannot access further details of the SSL configuration (such as public key).

2. Try to connect using MySQL client

   `% mysql -uyour_username -p -h rds_hostname_from_...