Author: Rahul

DKIM or DomainKeys Identified Mail is an authentication protocol used to validate the identity of a sender. It’s an important tool for preventing email spoofing, which is when a person impersonates another user and sends emails with their name and address. DKIM Key works by using an OpenDKIM or Domain Key to sign each message sent. The key is an encrypted string of characters unique to the sender and is used to verify the message comes from the sender’s domain. This makes it harder for malicious actors to send forged messages. DKIM Key also allows receivers to reject messages that…

Docker is a platform used to develop, ship, and run applications inside containers. One of the common tasks when working with Docker is to transfer files between the host machine and the container. In this article, we will explore how to copy files from a host machine to a Docker container using the docker cp command. Understanding the docker cp command The docker cp command allows you to copy files or directories between a container and the local filesystem. The syntax is: docker cp [OPTIONS] SRC_PATH CONTAINER:DEST_PATH SRC_PATH: This is the source file or directory on the host machine that…

Docker has become a popular tool for containerization, simplifying the deployment and management of applications across various environments. However, as you work with Docker, you may accumulate a large number of containers that are no longer needed. To maintain a clean and efficient system, it is important to know how to stop and delete these containers. In this article, we will provide a comprehensive guide on how to stop and delete all Docker containers efficiently. Contents Understanding Docker containers Listing Docker containers Stopping all Docker containers Deleting all Docker containers Cleaning up unused containers, images, and volumes Automating container cleanup…

HDFS is the Hadoop Distributed File System. It’s a distributed storage system for large data sets which supports fault tolerance, high throughput, and scalability. It works by dividing data into blocks that are replicated across multiple machines in a cluster. The blocks can be written to or read from in parallel, facilitating high throughput and fault tolerance. HDFS provides RAID-like redundancy with automatic failover. HDFS also supports compression, replication, and encryption. The most common use case for HDFS is storing large collections of data such as image and video files, logs, sensor data, and so on. Creating Directory Structure with…

A Zombie Process is a process that has completed execution but its parent process has not yet terminated it and released its resources. In Unix/Linux, a process that is in this state is considered a Zombie process. These processes take up valuable system resources and can cause stability issues if not properly handled. Here’s a step-by-step guide to understanding and handling Zombie processes in Unix/Linux: Identifying Zombie Processes: To identify Zombie processes, you can use the ps command and look for processes in the “Z” state. For example: ps -eo pid,state,cmd | grep Z Understanding the Causes: Zombie processes are…

Understanding unstructured data and analyzing massive amounts of data is a different ball game today. And so, businesses have resorted to Apache Hadoop and other related technologies to manage their unstructured data more efficiently. Not just businesses but also individuals are using Apache Hadoop for various purposes, such as analyzing large datasets or creating a website that can process user queries. However, installing Apache Hadoop on Ubuntu may seem like a difficult task for users new to the world of Linux servers. Fortunately, you don’t need to be an experienced system administrator to install Apache Hadoop on Ubuntu. The following…

If you’re new to Fedora, you might not know that there are different versions of it. The latest version of Fedora is called the “Current” version. This means there are older versions that you can upgrade from. In this article, we’ll explain how to upgrade your Fedora version. Keep reading to learn more. Fedora Versions Fedora releases a new version about every six months. This means you get the latest features and security updates regularly. Each version has a number to help you know which one you’re using. For example, the latest version of Fedora in February 2023 was Fedora…

PostgreSQL is an open-source database management system (DBMS) that is widely used for its reliability, performance, and scalability. It is also known as a third-generation DBMS because it retains data in secondary storage rather than memory, making it less prone to performance degradation and other issues associated with dynamic memory allocation. In this article, we’ll show you how to install PostgreSQL on macOS. In this blog post, you will learn how to install PostgreSQL on macOS with Homebrew by following the steps below. Once you complete the installation process, you’ll be able to create databases, tables, and other objects inside…

A number is a combination of 0-9 digits—the Bash variables stores all value in the form of strings. Even if the stored value is in string format, we can perform all the arithmetical operations if the stored value is a valid number. As a best practice, we should verify the values of variables before performing the arithmetic operations. A number can be an integer number, a floating point number, or a positive/negative number that prefixes with a “+ and -” symbol. In this tutorial, we have discussed a few methods to verify that the variable contains only digits, integers, and…

How to install VirtualBox on macOS? A step-by-step tutorial to install VirtualBox on the macOS system along with an extension pack. VirtualBox is a popular, cross-platform virtual machine manager that allows you to create virtual machines (VMs) on your Mac. VMs can be used to run different operating systems at the same time. They’re also useful for testing software in isolation, without risking your real computer. In order to install VirtualBox on macOS, you need to have a Mac with a 64-bit processor running macOS 10.11 or higher. VirtualBox runs on Windows, macOS, and Linux, and supports a wide range…