search
HomeWeb Front-endFront-end Q&AHow to query process PID in Node.js

Node.js is an open source JavaScript running environment based on the Chrome V8 engine that can run JavaScript on the server side. It adopts an event-driven, non-blocking I/O model, making it ideal for lightweight, efficient, real-time data interaction applications.

When developing Node.js applications, sometimes we need to query the PID of the current process, that is, the process ID. PID is a numeric type that uniquely identifies a process in the system. Normally, we can query the PID of a process through shell commands or system APIs. This article will introduce how to query the process PID in Node.js.

Querying PID through process object

In Node.js, you can use the process object to obtain information about the current process, including the PID of the process. The process object is one of the global objects of Node.js and we can access it at any time. The following is a sample code to get the PID of the current process:

console.log('当前进程的 PID 是:', process.pid);

The above code will output the PID of the current Node.js process.

Querying PID by process name

In addition to querying the PID of the current process, sometimes we also need to query the PID of a specific process. At this time, the PID can be queried by the process name. In Linux/macOS, you can use the shell command ps to query process information. In Windows, you can use the tasklist command to query process information. The following is a sample code to obtain the PID of a specified process:

Linux/macOS

const { exec } = require('child_process');

exec('pgrep node', (err, stdout, stderr) => {
  if (!err && stdout) {
    console.log('当前 Node.js 进程的 PID 是:', stdout.trim());
  }
});

The above code will query the currently running Node.js process through the shell command pgrep node PID and output the results.

Windows

const { exec } = require('child_process');

exec('tasklist /FI "IMAGENAME eq node.exe" /NH', (err, stdout, stderr) => {
  if (!err && stdout) {
    const pids = stdout.trim().split('\n').map(line => {
      const columns = line.trim().split(/\s+/);
      return parseInt(columns[1]);
    }).filter(pid => !isNaN(pid));
    console.log('当前 Node.js 进程的 PID 是:', pids[0]);
  }
});

The above code will query the PID of the currently running Node.js process through the shell command tasklist /FI "IMAGENAME eq node.exe" /NH. and output the result.

Summary

This article introduces two methods for Node.js to query process PID: querying the current process PID through the process object, and querying the specified process PID through the process name. Both methods are very useful for Node.js applications that need to manage processes.

The above is the detailed content of How to query process PID in Node.js. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Keys in React: A Deep Dive into Performance Optimization TechniquesKeys in React: A Deep Dive into Performance Optimization TechniquesMay 01, 2025 am 12:25 AM

KeysinReactarecrucialforoptimizingperformancebyaidinginefficientlistupdates.1)Usekeystoidentifyandtracklistelements.2)Avoidusingarrayindicesaskeystopreventperformanceissues.3)Choosestableidentifierslikeitem.idtomaintaincomponentstateandimproveperform

What are keys in React?What are keys in React?May 01, 2025 am 12:25 AM

Reactkeysareuniqueidentifiersusedwhenrenderingliststoimprovereconciliationefficiency.1)TheyhelpReacttrackchangesinlistitems,2)usingstableanduniqueidentifierslikeitemIDsisrecommended,3)avoidusingarrayindicesaskeystopreventissueswithreordering,and4)ens

The Importance of Unique Keys in React: Avoiding Common PitfallsThe Importance of Unique Keys in React: Avoiding Common PitfallsMay 01, 2025 am 12:19 AM

UniquekeysarecrucialinReactforoptimizingrenderingandmaintainingcomponentstateintegrity.1)Useanaturaluniqueidentifierfromyourdataifavailable.2)Ifnonaturalidentifierexists,generateauniquekeyusingalibrarylikeuuid.3)Avoidusingarrayindicesaskeys,especiall

Using Indexes as Keys in React: When It's Acceptable and When It's NotUsing Indexes as Keys in React: When It's Acceptable and When It's NotMay 01, 2025 am 12:17 AM

Using indexes as keys is acceptable in React, but only if the order of list items is unchanged and not dynamically added or deleted; otherwise, a stable and unique identifier should be used as the keys. 1) It is OK to use index as key in a static list (download menu option). 2) If list items can be reordered, added or deleted, using indexes will lead to state loss and unexpected behavior. 3) Always use the unique ID of the data or the generated identifier (such as UUID) as the key to ensure that React correctly updates the DOM and maintains component status.

React's JSX Syntax: A Developer-Friendly Approach to UI DesignReact's JSX Syntax: A Developer-Friendly Approach to UI DesignMay 01, 2025 am 12:13 AM

JSXisspecialbecauseitblendsHTMLwithJavaScript,enablingcomponent-basedUIdesign.1)ItallowsembeddingJavaScriptinHTML-likesyntax,enhancingUIdesignandlogicintegration.2)JSXpromotesamodularapproachwithreusablecomponents,improvingcodemaintainabilityandflexi

What type of audio files can be played using HTML5?What type of audio files can be played using HTML5?Apr 30, 2025 pm 02:59 PM

The article discusses HTML5 audio formats and cross-browser compatibility. It covers MP3, WAV, OGG, AAC, and WebM, and suggests using multiple sources and fallbacks for broader accessibility.

Difference between SVG and Canvas HTML5 element?Difference between SVG and Canvas HTML5 element?Apr 30, 2025 pm 02:58 PM

SVG and Canvas are HTML5 elements for web graphics. SVG, being vector-based, excels in scalability and interactivity, while Canvas, pixel-based, is better for performance-intensive applications like games.

Is drag and drop possible using HTML5 and how?Is drag and drop possible using HTML5 and how?Apr 30, 2025 pm 02:57 PM

HTML5 enables drag and drop with specific events and attributes, allowing customization but facing browser compatibility issues on older versions and mobile devices.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.