How to batch rename files in Node.js

In this blog post, I will explain how to rename a group of files.

The same process can move the file to another folder, because the path of the file will be renamed when renaming.

The motivation for this task is this: In Hugo, we can write a blog post as a file as follows:

We can also add them to a folder that contains an file:


The difference is that with folder we can add images and associate them more easily to a blog post.

I could have done the change manually, but I had about 50 files in the folder and I didn’t really want to do that job.

I wanted it to happen automatically.

Let’s start by requiring one core module we’re going to use: fs. As it is a core module, there’s no need to npm install it.

const fs = require('fs')

Then, get a reference to the current folder. I suppose we’re going to run the script in the same folder where we want to perform this change.

__dirname is the variable that always points to the current working folder.

I get a list of all the files and folders:

const files = fs.readdirSync(__dirname)

Then I filter out only the items that end with .md:

for (const file of files) {
  if (file.endsWith('.md')) {

Once we have the file reference, which represents the filename, we can call fs.rename().

This function accepts 3 parameters:

  1. the current path
  2. the path we want to move to
  3. an callback fired if there’s an error

The current path is:

__dirname + '/' + item

The path we want to move to is:

__dirname + '/' + item.replace('.md', '') + '/'

See? We create a new folder from the file name, then we append

  __dirname + '/' + item,
  __dirname + '/' + item.replace('.md', '') + '/',
  err => {

Here’s the full code:

const fs = require('fs')
const files = fs.readdirSync(__dirname)

for (const file of files) { if (file.endsWith(’.md’)) { fs.rename( __dirname + ‘/’ + item, __dirname + ‘/’ + item.replace(’.md’, ‘’) + ‘/’, err => { console.log(err) } ) } }

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