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Command line tool to help you keep configuration (package.json, .gitignore, .eslintrc, etc.) of your open source projects in sync.


  • Will not overwrite your data if you don’t want it to
  • Minimal changes: will keep the original file formatting or read the style from EditorConfig
  • Minimal configuration: will try to infer configuration from the project itself or from the environment
  • Bunch of customizable tasks included
  • Tools to work with JSON, YAML, INI, Markdown and new line separated text files
  • Easy to write your own tasks
  • Share tasks via npm and group them into presets

Table of contents


Most of the available tools are template based. Template approach works moderately well for new project generation but doesn’t work well for updating. Mrm’s approach is closer to codemods than templates.

Read more in my article, Automating open source project configuration with Mrm, or watch my talk on Mrm.


npm install -g mrm


Print a list available of tasks:


Run a task or an alias

mrm gitignore
mrm license

Run multiple tasks:

mrm gitignore license

Override config options (or run without a config file):

mrm license --config:name "Gandalf the Grey" --config:email "" --config:url ""

Custom config and tasks folder:

mrm license --dir ~/unicorn

Run a task from a preset (globally installed mrm-preset-unicorn npm package, read more about preset):

mrm license --preset unicorn

Usage via npx

If you have npm 5.3 or newer you can use mrm without installation:

npx mrm
npx mrm gitignore
npx mrm license --config:name "Gandalf the Grey" --config:email "" --config:url ""


Create ~/.mrm/config.json or ~/dotfiles/mrm/config.json:

  "indent": "tab", // "tab" or number of spaces
  "readmeFile": "", // Name of readme file
  "licenseFile": "", // Name of license file
  "aliases": {  // Aliases to run multiple tasks at once
    "node": ["license", "readme", "editorconfig", "gitignore"]

See tasks docs for available config options.

Config file isn’t required, you can also pass config options via command line. Default tasks will try to read data fom your npm and Git configuration.


These tasks are included by default:

Writing your own tasks

Create either ~/.mrm/<TASK>/index.js or ~/dotfiles/mrm/<TASK>/index.js. If <TASK> is the same as one of the default tasks your task will override a default one.

The simplest task could look like this:

// Mrm module to work with new line separated text files
const { lines } = require('mrm-core');

function task() {
  // Read .gitignore if it exists
    // Add lines that do not exist in a file yet,
    // but keep all existing lines
    .add(['node_modules/', '.DS_Store'])
    // Update or create a file

task.description = 'Adds .gitignore';
module.exports = task;

Tasks can also be async by adding the async keyword or returning a Promise.

async function task () {

// or
function task () {
  return new Promise(() => {

If your tasks have dependencies (such as mrm-core) you should initialize the mrm folder as an npm module and list your dependencies there:

cd ~/.mrm # or cd ~/dotfiles/mrm
npm init -y
npm install --save mrm-core

mrm-core is an utility library created to write Mrm tasks, it has function to work with common config files (JSON, YAML, INI, Markdown), npm dependencies, etc.

Let’s take a look at a more complicated task:

const {
  // JSON files
  // package.json
  // New line separated text files
  // Install npm packages
} = require('mrm-core');

function task(config) {
  // Task options
  // mrm eslint --config:name pizza
  const { name, eslintPreset } = config
      // Default value
      eslintPreset: 'eslint:recommended'
    // Required option

  // Use custom preset package from npm
  const packages = ['eslint'];
  if (eslintPreset !== 'eslint:recommended') {

  // Create or update .eslintignore

  // Read project’s package.json
  const pkg = packageJson();

    // Add lint script
    .setScript('lint', 'eslint . --cache --fix')
    // Add pretest script
    .prependScript('pretest', 'npm run lint')

  // Read .eslintrc if it exists
  const eslintrc = json('.eslintrc');

  // Use Babel parser if the project depends on Babel
  if (pkg.get('devDependencies.babel-core')) {
    const parser = 'babel-eslint';
    eslintrc.merge({ parser });

  // Set preset
  eslintrc.set('extends', eslintPreset).save();

  // Install npm dependencies

task.description = 'Adds ESLint';
module.exports = task;

There are more methods in mrm-core — check out the docs and the default tasks.

Sharing tasks via npm

The basic file structure of a shared task looks like this:

├── index.js
├── package.json

index.js is the same as described in the previous section. And the package.json would look like this:

  "name": "mrm-task-unicorn",
  "version": "0.1.0",
  "description": "Unicorn task for Mrm",
  "author": {
    "name": "Artem Sapegin",
    "url": ""
  "homepage": "",
  "repository": "sapegin/mrm-tasks",
  "license": "MIT",
  "engines": {
    "node": ">=4"
  "main": "index.js",
  "files": [
  "keywords": [
  "dependencies": {
    "mrm-core": "^2.1.3"

The package name should should follow this pattern: mrm-task-<TASK>, otherwise you’ll have to type full package name when you run a task:

mrm unicorn # mrm-task-unicorn
mrm @mycompany/unicorn-task # @mycompany/unicorn-task

Custom presets

Preset is an npm package (or a directory) that contains a config and tasks.

The file structure looks like this:

├── task1
│   └── index.js
├── task2
│   └── index.js
├── config.json
├── package.json

And the package.json would look like this:

  "name": "mrm-preset-default",
  "version": "0.1.0",
  "description": "Common tasks for Mrm",
  "author": {
    "name": "Artem Sapegin",
    "url": ""
  "homepage": "",
  "repository": "sapegin/mrm-tasks",
  "license": "MIT",
  "engines": {
    "node": ">=4"
  "main": "config.json",
  "files": [
  "keywords": [
  "dependencies": {
    "mrm-core": "^2.1.3",
    "mrm-task-gitignore": "^0.1.0"

See the Writing custom tasks section above to learn how to write Mrm tasks. To add a task to a preset put it into a <TASK>/index.js file in your preset package folder.

If you want to use a task from npm (or any default task), you should include it as a dependency. That way you can be sure that you’ll always have a task version that works for your project.

For example, if you want to use mrm-task-gitignore task, you need to create a gitignore/index.js file in your preset package folder:

module.exports = require('mrm-task-gitignore');

The package name should should follow this pattern: mrm-preset-<TASK>, otherwise you’ll have to type full package name when you run a task:

mrm license --preset unicorn # mrm-preset-unicorn
mrm license --preset @mycompany/unicorn-preset # @mycompany/unicorn-preset

Config resolution rules

  • <DIR>/config.json if --dir <DIR> command line option was passed
  • $HOME/dotfiles/mrm/config.json
  • $HOME/.mrm/config.json

if you’re passing a --preset <PRESET> command line option, then the only task directory will be:

  • mrm-preset-<PRESET>/config.json

Task resolution rules

  • <DIR>/<TASK>/index.js if --dir <DIR> command line option was passed
  • $HOME/dotfiles/mrm/<TASK>/index.js
  • $HOME/.mrm/<TASK>/index.js
  • mrm-task-<TASK>/index.js, where mrm-task-<TASK> is an npm package name
  • <TASK> in mrm-preset-default

if you’re passing a --preset <PRESET> command line option, then the only task directory will be:

  • mrm-preset-<PRESET>/<TASK>/index.js


How to use Mrm with Lerna?

To run a task for each package in a Lerna repository:

./node_modules/.bin/lerna exec -- mrm <TASK>

How to infer user metadata, like user name or email?

Use the user-meta package to read user name, email and URL from .npmrc or .gitconfig:

const meta = require('user-meta');
module.exports = function task(config) {
	const { name, email, url } = config
		.require('name', 'email', 'url')
  /* ... */

How to infer GitHub user name?

Use the git-username package:

const gitUsername = require('git-username');
module.exports = function task(config) {
	const { github } = config
			github: gitUsername(),
  /* ... */

Change log

The change log can be found on the Releases page.


Everyone is welcome to contribute. Please take a moment to review the contributing guidelines.

Authors and license

Artem Sapegin and contributors.

MIT License, see the included file.