Shorts

In Linux, a zombie process is a state that a child process enters when it has finished executing, but its exit status has not yet been collected by its parent process. Zombie processes are essentially dead processes that are waiting for their parent process to retrieve their exit status.

You might have seen the command "patch -p2" or an entry in composer.json when using cweagans/composer-patches like the following.

"patchLevel": {
    "drupal/core": "-p2"
}

In the command "patch -p2," the "-p2" flag specifies the patch level.

The "patch" command is used to apply changes, or patches, to source code files. The "-p" flag followed by a number tells the patch command how many directory levels to strip from the file paths mentioned in the patch file.

Setting the Content-Security-Policy (CSP) header correctly is an essential step in enhancing the security of your web application. The CSP header allows you to define a policy that restricts the types of content that can be loaded by a web page, thereby mitigating risks such as cross-site scripting (XSS) and data injection attacks. Here's a general guide on how to correctly set CSP headers:

In PHP, the `final` keyword is used to restrict the inheritance and overriding of methods and classes. Here's what it does in different contexts:

In PHP, there are three types of inheritance:

Drupal made a significant shift towards adopting the object-oriented programming (OOP) paradigm starting with its major release, Drupal 8 many many moons ago. I'm sure many wanted to know why. Drupal addressed the criticism of the lack of explicit use of object-oriented programming (OOP) in Drupal's source code and API by explaining the reasons behind their design choices. Here are the key points they mentioned:

In Drupal, you can override a controller class by implementing a custom route subscriber. Here are the steps to do so:

1. Create a custom module: Create a custom Drupal module if you haven't already. You can do this by creating a new folder with the module name in the modules/custom directory of your Drupal installation, and adding a *.info.yml file to define the module.

In Drupal, you can override a service class using a service provider class. Here are the steps to do so:

1. Create a custom module: Create a custom Drupal module if you haven't already. You can do this by creating a new folder with the module name in the modules/custom directory of your Drupal installation, and adding a *.info.yml file to define the module.

Here's how you can create nested vertical or horizontal tabs in Drupal Form API:

1. Define your configuration form using the Drupal Form API by creating a new form class that extends ConfigFormBase or FormBase.

2. Add a vertical_tabs element to your form using the Drupal\Core\Render\Element\VerticalTabs class. This will create the top-level vertical tabs.

3. Inside each top-level vertical tab, add another vertical_tabs element to create the nested vertical tabs.

To increase the PHP memory limit for all PHP CLI (Command Line Interface) commands in Drupal, you can add a configuration to the settings.php file. Here's how to do it:

1. Open the settings.php file for your Drupal installation. This file is usually located in the sites/default folder of your Drupal installation.

2. Add the following lines of code to the bottom of the settings.php file: