Category Archives: General


In computing, virtualization refers to the act of creating a virtual (rather than actual) version of something, including virtual computer hardware platforms, storage devices, and computer network resources.

Virtualization began in the 1960s, as a method of logically dividing the system resources provided by mainframe computers between different applications. Since then, the meaning of the term has broadened

Virtualization lets you run several operating systems on the same hardware in parallel.

Virtualization allows separation of services, tasks and users in distinct virtual machines.


Linux distribution

A Linux distribution (often abbreviated as distro) is an operating system made from a software collection, which is based upon the Linux kernel and, often, a package management system.

These distributions contain software versions that have proven to be stable even if it is not the recent version in order to minimize problems.



The combination of Linux, Apache, MySQL and PHP or other programming languages.

LAMP is an archetypal model of web service stacks, named as an acronym of the names of its original four open-source components: the Linux operating system, the Apache HTTP Server, the MySQL relational database management system (RDBMS), and the PHP programming language. The LAMP components are largely interchangeable and not limited to the original selection. As a solution stack, LAMP is suitable for building dynamic web sites and web applications.

Since its creation, the LAMP model has been adapted to other componentry, though typically consisting of free and open-source software. For example, an equivalent installation on the Microsoft Windows family of operating systems is known as WAMP and an equivalent installation on macOS is known as MAMP.


Cloud computing

Cloud computing is shared pools of configurable computer system resources and higher-level services that can be rapidly provisioned with minimal management effort, often over the Internet. Cloud computing relies on sharing of resources to achieve coherence and economies of scale, similar to a public utility.

Cloud Computing provides new tools to manage IT resources.

From the business perspective, Cloud Computing means outsourcing or centralization of IT operations.


vi editor replace all

The syntax for replacing one string with another string in the current line is


Here “pattern” represents the old string and “replace” represents the new string. For example, to replace each occurrence of the word “lemon” in a line with “orange,” type:


The syntax for replacing every occurrence of a string in the entire text is similar. The only difference is the addition of a “%” in front of the “s”:


Thus repeating the previous example for the entire text instead of just for a single line would be:


We can’t find the role for the user you wanted.

Edit the file vendor/magento/module-authorization/Model/Acl/AclRetriever.php at line# 85 and replace the below code

   if (!$role) {
throw new AuthorizationException(
__('We can\'t find the role for the user you wanted.')
$allowedResources = $this->getAllowedResourcesByRole($role->getId());

With this one

if (!$role) {
            $allowedResources = array();

Once success, please revert back the file.