CRUD with File System Create, Read, Update, Delete Files

Learn how to perform Create, Read, Update, and Delete operations using Node.js's built-in fs module. We'll also handle terminal inputs to do these operations dynamically.


Basic File Operations

const fs = require("fs");


Create New Files

fs.writeFileSync("files/apple.txt", "This is fruit");
fs.writeFileSync("files/banana.txt", "This is fruit");

writeFileSync() creates files. If file already exists, it will overwrite.


Delete a File

fs.unlinkSync("files/banana.txt");

unlinkSync() removes a file.


Read a File

const data = fs.readFileSync("files/apple.txt", "utf-8");
console.log(data);

readFileSync() reads file content. "utf-8" ensures readable string output.


Update a File

fs.appendFileSync("files/apple.txt", " and this is good for health");

appendFileSync() adds new content to existing file.


CRUD Operations with Terminal Input

Now let’s make this dynamic — use terminal commands like Write, Read, update, or delete.

const fs = require("fs");
const operation = process.argv[2];

process.argv[] gives command-line input.


Create File from Terminal

node index.js Write fileName "your content"


if (operation === "Write") {
const name = process.argv[3];
const content = process.argv[4];
fs.writeFileSync(`files/${name}.txt`, content);
console.log("File Created");
}


Read File from Terminal

node index.js Read fileName


else if (operation === "Read") {
const name = process.argv[3];
const data = fs.readFileSync(`files/${name}.txt`, "utf-8");
console.log(data);
}


Update File from Terminal

node index.js update fileName "new content"



else if (operation === "update") {
const name = process.argv[3];
const content = process.argv[4];
fs.appendFileSync(`files/${name}.txt`, content);
}


Delete File from Terminal

node index.js delete fileName


else if (operation === "delete") {
const name = process.argv[3];
fs.unlinkSync(`files/${name}.txt`);
}


Fallback Case

else {
console.log("Operation not found");
}



Example Test

node index.js Write hello "This is demo"
node index.js Read hello
node index.js update hello " updated!"
node index.js delete hello