How to use nodejs command line

As a very popular back-end programming language, Node.js not only supports front-end development, but also can develop back-end applications quickly and efficiently. Among them, the command line is a very important function in Node.js, which can help developers quickly operate and debug and improve development efficiency. This article will introduce the basic use of the Node.js command line and some common techniques.

What is the command line?

The command line is a text-based interface provided by the operating system to interact with the computer. When using the command line interface, users need to enter specific instructions to perform operations. In Node.js, the command line interface is also one of the important development tools. By using the command line, developers can perform some simple and quick operations, such as creating and deleting folders, running JavaScript files, etc.

Basic usage of Node.js command line

To use the command line in Node.js, you first need to open a terminal or command line window, and then enter thenodecommand, You can enter the Node.js command line interface.

The following are some basic Node.js command line operations:

• Enterconsole.log("Hello, World!")in the command line, It will output "Hello, World!";
• Enter in the command linelet a = 1; let b = 2; console.log(a b), it will output 3;
• Enter.exitin the command line to exit the Node.js command line interface.

Through the above operations, you can see that the use of the Node.js command line interface is very similar to the use of the JavaScript language. In addition to the above general usage, the Node.js command line also provides some useful operations. Some common operation techniques will be introduced below.

Commonly used Node.js command line techniques

1. View Node.js version information

Enternode -vin the command line to view Currently installed Node.js version information.

2. Run JavaScript files

Use the Node.js command line to run JavaScript files. Enternode example.json the command line to run the JavaScript file namedexample.js.

3. Use modules

In Node.js, we can use modules to enhance the readability and maintainability of the code. When using a module on the command line, you need to use therequirecommand to introduce the module. Enterlet fs = require("fs")on the command line to introduce the file system module namedfs.

4. Debug in the command line

You can also perform Debug operations and use the debugger in the Node.js command line. Use the commandnode inspect example.jsto enter the Debugger interface, and use thereplcommand to view variables and execute expressions.

5. Use NPM in the command line

NPM is the package management tool that comes with Node.js. You can use NPM in the Node.js command line to download, install, and update modules. Wait for operations. For example, enternpm install expresson the command line to download and install the module named express.

Summary

The Node.js command line is a very important tool that can help developers operate their work quickly and efficiently. This article introduces some simple basic operations and common techniques on the Node.js command line, including viewing Node.js version information, running JavaScript files, using modules, debugging, and using NPM to install modules. I hope that through this article, you can understand and master the use of the Node.js command line and improve development efficiency.

The above is the detailed content of How to use nodejs command line. For more information, please follow other related articles on the PHP Chinese website!