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Open Source Articles
Page 21 of 123
How to encrypt a large file using openssl?
OpenSSL is a powerful cryptographic toolkit that provides various security functions including file encryption. It comes pre-installed on most Linux distributions, but can be installed via package managers if needed. This article demonstrates how to encrypt large files using OpenSSL's public-key cryptography features. Understanding Encryption Types Before diving into file encryption, it's important to understand the two main encryption approaches: Symmetric (Secret-key) encryption − Uses the same key for both encryption and decryption Asymmetric (Public-key) encryption − Uses separate keys for encryption and decryption Public-key encryption is more secure as it eliminates key-sharing concerns, ...
Read MoreHow to swap two files in Linux command line?
As system administrators or DevOps professionals, we often need to exchange file contents. For example, you might have a backup file /etc/passwd.backup that you want to restore to /etc/passwd, while preserving the current content by moving it to the backup file. This operation is called file swapping − exchanging the actual content of two files, not their locations. When we talk about swapping two files on Linux, we mean exchanging their content while keeping their names and locations unchanged. This tutorial demonstrates practical methods to accomplish this task using command line tools. Example Files Setup Let's create ...
Read MoreThreads vs Processes in Linux
A process is the execution of a program that allows you to perform the appropriate actions specified in a program. It can be defined as an execution unit where a program runs. The OS helps you to create, schedule, and terminate the processes which are used by the CPU. The other processes created by the main process are called child processes. A thread is an execution unit that is part of a process. A process can have multiple threads, all executing at the same time. It is a unit of execution in concurrent programming. Threads within the same process ...
Read MoreHow is Docker different from a Virtual Machine?
When we speak about efficient utilization and proper allocation of computer resources, both virtual machines and Docker containers are effective in their own ways. In the past few years, Docker containers have gained tremendous popularity among organizations of all sizes. It is very important to understand the use-cases and purposes that they both serve if you want to decide which of the two is better for your requirements. However, before we start the discussion make sure that you have the basic knowledge of what Docker is. You can refer to our tutorial on Docker. So without any further ado, ...
Read MoreBest Command Line HTTP Client for Linux
In this tutorial, we will explore some of the most commonly used and famous HTTP clients that are present in Linux. A HTTP Client is a software that is mainly used to allow us to download files from the Internet. The primary reason for using HTTP clients is generally to download files, but these can also be used in case we want to debug or interact with a web server or multiple web servers. Now, let's consider the most famous HTTP Clients that are used. HTTPie With the name that almost resembles of the famous web protocol ...
Read MoreHow to write Stdout to a file with colors?
When working with command-line tools that produce colorized output, preserving these colors when redirecting to files can be challenging. By default, most programs detect when their output is redirected and strip away ANSI color codes. This article covers various methods to capture colored terminal output in files while maintaining the original formatting. Using Grep with Color Preservation The grep command searches for text patterns using regular expressions. To preserve colors when redirecting output, use the --color=always option. Syntax $ grep [options] pattern [files] Example First, create a sample file and then use ...
Read MoreDocker host network vs bridge network
Docker provides two primary single-host networking modes: host and bridge networks. Single-host networks operate locally on each individual Docker host, providing different levels of network isolation and connectivity options. In host networking, Docker containers share the host's network stack directly, eliminating network isolation between container and host. With bridge networking, containers run in an isolated network namespace and require explicit port mapping to communicate with external systems. Host Network Mode Host networking allows containers to use the host's network interface directly. This mode provides maximum performance but sacrifices network isolation. Creating a Container with Host Network ...
Read MoreSending Emails From Terminal In Linux
You can send emails from the terminal in Linux by using the command line tool called mail. This tool is typically pre-installed on most Linux distributions. To send an email, you would use the syntax − echo "message body" | mail -s "subject" recipient@email.com You can also include attachments by using the -a option and specifying the path to the file you want to attach. echo "message body" | mail -s "subject" -a /path/to/attachment recipient@email.com You can also use other command line mail clients such as mutt, mailx, and msmtp. Architecture ...
Read MoreDifference Between .bashrc, .bash-profile, and .profile
When working with the command line on Unix or Linux systems, three configuration files play crucial roles in setting up your shell environment: .bashrc, .bash_profile, and .profile. Understanding when and how these files are executed is essential for effective shell customization and environment management. How Shell Configuration Files Work These files contain shell commands that are automatically executed at specific times during shell initialization. The key difference lies in when they are executed: Login shells − Started when you log into the system (SSH, console login) Non-login shells − Started when you open a new terminal ...
Read MoreHow to Clean a Linux Zombie Process
A Linux zombie process is a process that has completed execution, but its parent process has not yet collected its exit status. These processes remain in the system's process table consuming minimal resources but can accumulate over time. Understanding how to identify, handle, and prevent zombie processes is essential for maintaining system health. Zombie processes occur when a child process finishes but the parent hasn't called wait() or waitpid() to read the child's exit status. The process becomes a "zombie" − neither fully alive nor completely dead. What Are Zombie Processes When a process terminates, it doesn't ...
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