Understanding Arrays and Objects in JavaScript

JavaScript, a versatile and widely-used programming language, offers powerful data structures that are essential for handling and manipulating data. Among these, arrays and objects are fundamental to effective JavaScript programming. This article introduces both arrays and objects, summarizing their characteristics and uses, and then compares them in a table format to highlight their similarities and … Read more

Managing Environment Variables in Linux Services: systemd vs init.d

Managing environment variables is crucial for configuring services on Linux. Depending on whether you are using systemd or init.d scripts to manage your services, the methods for setting environment variables differ slightly. This guide explores how to set environment variables in both systemd and init.d, providing flexibility and customization options for your services.Using systemdSystemd is … Read more

Run a program forever in linux

Running programs indefinitely ensures that services and applications are always available, reliable, and capable of handling real-time data and tasks effectively. So People often want to run programs indefinitely on computers. In Linux, if you have root access, you can use systemctl to manage services and ensure that they run continuously. Without root access, you … Read more

The simplest scatter boundary in electromagnetic

In computational electromagnetics, the scatter boundary (also known as the radiation boundary or far-field boundary) is an artificial boundary that simulates the infinite extent of free space surrounding a finite computational domain. This boundary is used to terminate numerical simulations, ensuring that the outgoing electromagnetic waves do not reflect back into the computational domain. For … Read more

Automation for Optimization in Comsol

The Optimization Module in COMSOL Multiphysics provides tools for optimizing designs by finding the best combination of parameters to satisfy certain objectives or constraints. It’s commonly used in engineering and physics simulations to optimize designs for various applications. Besides the parameters sweeps and basic design parameters optimizations, it provides some automation for more complex optimization. … Read more

Detect proxies and user IP by PHP

To get the IP address of a visitor in PHP, you can use the $_SERVER superglobal array, specifically the $_SERVER[‘REMOTE_ADDR’] variable. To handle cases where the visitor’s IP address is masked by proxies or load balancers, you can check for specific HTTP headers that may contain the original IP address. Common proxy headers include X-Forwarded-For, … Read more

Run directly or in docker container

Containerization is a technology that allows you to package an application along with its dependencies and runtime environment into a self-contained unit called a container. Docker provides tools and a runtime environment to create, deploy, and manage containers efficiently. The advantages and disadvantages of Docker: Advantages of Docker Disadvantages of Docker Isolation and Portability Learning … Read more