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Articles by Satish Kumar
Page 3 of 94
How to Change SSH Port in Linux?
Secure Shell (SSH) is a network protocol that provides encrypted communication over an insecure network. By default, SSH listens on port 22, which is well-known and frequently targeted by attackers. Changing the SSH port to a non-standard number adds an extra layer of security through security through obscurity. Checking Current SSH Port Before changing the SSH port, verify which port your SSH service is currently using. Use the following command to check the current configuration: sshd -T | grep port This command will display output similar to: port 22 addressfamily any listenaddress ...
Read MoreHow to Change User Password in Ubuntu?
If you are a Linux user, there is no doubt that you have heard of Ubuntu OS. Ubuntu is an open-source operating system based on the Debian architecture and is one of the most popular distributions of Linux. Its user-friendly interface and versatile nature makes it a great operating system for both personal and professional use. As with any operating system, password security in Ubuntu is of utmost importance. With cyberattacks increasing day by day, secure passwords are essential to keep your information safe from unauthorized access. This guide aims to simplify the process of changing your user ...
Read MoreHow to Work With GitHub Flavored Markdown in Linux?
GitHub Flavored Markdown (GFM) is an enhanced version of standard Markdown developed by GitHub, featuring additional syntax elements that make it perfect for technical documentation, README files, and collaborative development. Unlike basic Markdown, GFM includes support for tables, task lists, strikethrough text, automatic URL linking, and syntax highlighting for code blocks. This guide demonstrates how to work with GFM on Linux systems, covering both basic syntax and advanced features with practical examples. Basic GitHub Flavored Markdown Syntax Headers and Text Formatting Headers use hash symbols (#) with levels from 1 to 6 − # ...
Read MoreHow to Write Scripts Using Awk Programming Language?
Awk is a powerful text-processing language named after its three original authors: Alfred Aho, Peter Weinberger, and Brian Kernighan. It's a versatile language primarily used for pattern scanning and processing, and is a staple of Unix scripting commonly used for tasks like data extraction, reporting, and data transformation. Awk scripts are quick to write and perform well for small to medium-sized tasks. This article introduces you to the basics of writing scripts using the Awk programming language. Basic Syntax An Awk program consists of a sequence of pattern-action pairs, written as − pattern { action ...
Read MoreHow to Zip a File in Linux?
File compression is a fundamental task in Linux system administration for managing storage space and efficiently transferring files. Linux provides several powerful command-line tools including gzip, zip, tar, and others for compressing files and directories. This guide covers the most commonly used compression methods and their practical applications. Using the gzip Command gzip (GNU zip) is a widely-used command for single file compression in Linux. It provides excellent compression ratios and is included by default in most distributions. gzip filename.txt This command compresses filename.txt and renames it to filename.txt.gz. The original file is replaced ...
Read MoreHtop - An Interactive Process Viewer for Linux
Htop is an interactive process viewer and system monitor for Linux that provides a superior alternative to the traditional top command. It offers real-time, color-coded visualization of system resources and running processes with an intuitive interface that allows users to manage processes interactively. Unlike the static output of top, Htop displays CPU, memory, and swap usage in colorful progress bars at the top of the screen, followed by a scrollable list of processes. This enhanced interface makes system monitoring more efficient and user-friendly for both beginners and experienced administrators. Installation Install Htop using your distribution's package manager: ...
Read MoreImplementing Mandatory Access Control with SELinux or AppArmor in Linux
Linux has built-in support for two types of Mandatory Access Control (MAC) systems: SELinux and AppArmor. Both systems add an additional layer of access control to the default Discretionary Access Control (DAC) that comes with Linux. In this article, we delve into the implementation of both systems, offering practical examples and their respective outputs. Understanding SELinux and AppArmor SELinux (Security-Enhanced Linux) is a Linux kernel security module that provides a mechanism for supporting access control security policies. It is a highly flexible MAC system that assigns labels to every object in the system (files, directories, ports, etc.) and ...
Read MoreInitial Server Setup and Configurations on RHEL 7
Red Hat Enterprise Linux (RHEL) 7 is a Linux-based operating system from Red Hat designed for businesses. This article provides a practical guide on performing initial server setup and configurations on RHEL 7. We will walk through essential first steps to prepare a RHEL 7 server for production use. Logging in as Root After your server boots, you will log in as the root user. The root user is the administrative user in a Linux environment with full system privileges. ssh root@your_server_ip Creating a New User After logging in as root, it's recommended ...
Read MoreInitial Server Setup with Ubuntu 20.04 18.04 and 16.04
Initial Server Setup is a critical first step after deploying a fresh Ubuntu server instance. Proper configuration ensures security, stability, and optimal performance for hosting applications or services. This guide covers essential setup procedures for Ubuntu versions 20.04, 18.04, and 16.04, including user management, security hardening, and basic service configuration. Prerequisites Before beginning the server setup process, ensure you have the following requirements − Fresh Ubuntu 20.04, 18.04, or 16.04 server instance Root access or user account with administrative privileges SSH client for remote server connection (e.g., OpenSSH, PuTTY) Server's public IP address System ...
Read MoreInstall RedMail with Virtual Domains, Webmail, SpamAssassin & ClamAV in Linux
Email communication remains an integral part of our personal and professional lives. Setting up a reliable and secure mail server is crucial for efficient communication within organizations or for personal use. Mail-in-a-Box (commonly called RedMail) is a fully-featured mail server solution that offers a comprehensive suite of tools to create virtual domains, access webmail, and enhance email security with SpamAssassin and ClamAV. In this article, we will guide you through the process of installing Mail-in-a-Box on a Linux system. Prerequisites Before diving into the installation process, ensure you have the following − A clean Ubuntu 18.04 ...
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