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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to grep string without filenames in Linux?
The grep command is a powerful tool for searching patterns in files. By default, when searching multiple files, grep displays the filename along with each matching line. However, sometimes you only want to see the matching lines without the filenames cluttering the output. Let's see a simple example where we grep a pattern in multiple files in a directory. Default grep Behavior with Multiple Files grep -i 'lp' Sample* Sample: The sample was printed via the internet. Sample: I believe lp cares about what the device is. Sample1: This was printed via the ...
Read MoreLinux Job Control &, disown, and nohup
Linux is an open-source operating system that is widely used in industry. One of the most notable features of Linux is its command-line interface (CLI), which provides flexibility and power to users. When working in the command line, it is common to run multiple commands concurrently. However, sometimes, you may want to control how these commands are executed and how they interact with each other. This is where job control comes in. Job Control Job control refers to the ability to manage and manipulate running processes in a Linux system. It allows users to start, stop, pause, resume, ...
Read MoreHow to Use Command Line Arguments in a Bash Script
In general, there are many ways to pass input to programming or scripting languages and sometimes there is a need to pass input from the command line instead of hardcoded values. Like any other programming or scripting language, bash scripting also supports command-line arguments. In this article, we will explore the syntax for command-line arguments, examine practical examples, and discuss the special variables used to handle these arguments effectively. Command-line Argument Syntax We already know how to run a bash script in Linux using either bash or sh command followed by the script filename. To pass command-line ...
Read MoreCopy on Write in Operating System
Copy-On-Write (COW) is a memory optimization technique used by operating systems to reduce overhead when creating new processes. It allows multiple processes to share the same memory pages until one process modifies them. When modification occurs, the OS creates a duplicate copy for the modifying process while other processes continue sharing the original page. How Copy on Write Works The COW mechanism operates through virtual memory management. When a process is created (like during fork()), instead of immediately copying all parent memory pages, the OS marks them as read-only and shares them between parent and child processes. ...
Read MoreAdvanced Copy Command with Progress Bar While Copying/Moving Files in Linux
As a Linux user, you may have found yourself in situations where you need to copy or move large files or directories from one location to another. This process can take some time, and it can be challenging to monitor the progress of copy or move operations. Fortunately, Linux provides several built-in commands that can help you copy or move files efficiently while also monitoring the operation's progress. In this article, we will discuss advanced copy commands with progress bars for copying/moving files in Linux. What is Advanced Copy Command? The Advanced Copy (or cp) command is ...
Read MoreMaster Boot Record
The Master Boot Record (MBR) is a critical 512-byte sector located at the very beginning of a storage device such as a hard disk drive or SSD. It contains essential information required to start the computer's boot process and load the operating system. The MBR consists of three main components: boot code, partition table, and disk signature. MBR Structure and Organization Master Boot Record (512 bytes) Boot Code (446 bytes) Partition Table (64 bytes) ...
Read MoreHow to Generate SSH Keys on Ubuntu?
SSH keys are cryptographic security keys that provide a more secure authentication method than passwords when connecting to remote servers. Ubuntu makes it easy to generate SSH key pairs using the ssh-keygen command-line tool. This guide will walk you through generating SSH keys on Ubuntu, understanding the different key types, and adding your public key to remote servers for secure authentication. The Benefits of Using SSH Keys over Passwords SSH keys offer significant security advantages over traditional password authentication: Enhanced Security − SSH keys use cryptographic algorithms that are nearly impossible to crack without access ...
Read MoreCreating Your Own Webserver and Hosting A Website from Your Linux Box
Creating your own web server and hosting a website from your Linux box is an excellent way to learn web development fundamentals and server administration. This article will guide you through setting up Apache web server, configuring it properly, and hosting your first website with essential security and performance optimizations. Installing Apache Apache is the most widely used web server software globally. It's free, open-source, and runs on virtually all operating systems. To install Apache on Ubuntu/Debian systems, open a terminal and run these commands: sudo apt update sudo apt install apache2 The first ...
Read MoreHow to insert a text at the beginning of a file in Linux?
In Linux, there are several ways to insert text at the beginning of a file. The most common and efficient method uses the sed command, which stands for stream editor. This command performs various operations like find, replace, insert, and delete on files without opening them in an editor. Using the sed Command The sed command can modify files in-place using the -i flag, making it perfect for inserting text at the beginning of files. Let's explore this with a practical example. Example Setup Consider a directory d1 containing text files. First, let's check the directory ...
Read MoreHash Functions and Hash Tables
Hashing is the process of generating a value from a text or a list of numbers using a mathematical function known as a hash function. Hash functions convert input data of arbitrary size into fixed-size hash values, which are used as indices in hash tables for efficient data storage and retrieval. Hash Functions Hash functions are algorithms that map data to fixed-size hash values. Here are the most commonly used hash functions − Division Method This is the simplest method to create a hash function. The hash function can be described as − h(k) ...
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