To test retina display, just adjust the screen pixel ratio.

The linux shell/bash terminal default behaviour is print output to the terminal (StdOut : Standard output). But sometimes we need to change this behaviour like save toi a file, display noting ... Here some exaple of user case.

To create a custom drush command, you must create a custom module like this (Here, mymodule).

To update a table you must create a custom module. Example , Here we use mymodule.

The structure of the examples are like:

namespace Drupal\mymodule\Tools;

class MyTools extends MyToolsBase {

...

}

...

class MyToolsBase {

  public function showClass() {

    $class_name = ....