#dev-tools #productivity #nodemon #file-monitoring

app lightmon

A lightweight, cross-platform, language-agnostic 'run code on file change' tool, inspired by Nodemon

3 unstable releases

0.2.0 Jun 5, 2021
0.2.0-alpha.0 Apr 20, 2021
0.1.3 Apr 7, 2021

#1635 in Command line utilities

GPL-3.0 license

589 lines


A lightweight, cross-platform, language-agnostic "run code on file change" tool, inspired by Nodemon

Why lightmon over nodemon?

There are many reasons to use lightmon over nodemon: it's faster, lighter, and can be used for all types of projects. Not only this, but lightmon is a drag and drop replacement for projects that use nodemon because lightman can parse existing nodemon.json config files.



By default, lightmon will automatically determine what kind of files it should watch based upon your project structure. For example, if a node_modules folder is present in the directory, lightmon will run in the node configuration, parsing your package.json to infer the correct command to run.

Supported languages

Watch patterns are the file patterns that lightmon will watch for file changes, and Exec commands are the list of commands that are executed when those events happen.


lightmon rust [cargo_subcommand]? [cargo_subcommand_args]?
Watch Patterns

[Cargo.toml, .rs]

Exec Commands

By default, the rust configuration will set the Exec command to cargo run if it's a binary project, and cargo test if it's a library.

However, you can override this behavior by specifying any valid cargo subcommand (and any arguments). For example, if you wanted to run cargo build --bin my_bin --all-targets, you can run the following:

lightmon rust build --bin my_bin --all-targets

Refer to lightmon help rust for more information.


Note: This configuration also works for React, React-Native, TypeScript, etc. i.e.: anything with a package.json!

lightmon node
Watch Patterns

[.jsx, .js, .css, .html]

Exec Commands

If there is a package.json in the root directory, lightmon attempts to resolve the exec command in the following order:

  • The value at scripts.start
  • node main where main is the value of the main key in package.json (the entry point of the project).

NOTE: The Exec command will fallback to node index.js if all of the above fail.

For example, the following package.json will result in the Exec command resolving to react-scripts start:

  "name": "calculator",
  "main": "index.js",
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build"


It's very tricky to infer what the patterns and exec commands could be, so we recommend using shell mode with a custom script (see below).

Shell (for unsupported languages or complicated builds)

lightmon shell -s <path> -w <patterns> Here users can specify the path to the shell script and which file types to watch for seperated by commas.

For example, let's say you have a python project with a file named start.py at the root of the project. Whenever you edit any .py files in the project, you want to re-run python start.py. To accomplish this, you could create a simple script called run.sh with the following contents:

python start.py

Now, you just run the following:

lightmon shell -s run.sh -w .py,.ipynb


There are many ways to install lightmon. We recommend using our install script as it is the fastest method.

$ curl -sSL https://raw.githubusercontent.com/reaganmcf/lightmon/master/install.sh | sh

But, we also support other popular package managers if you would rather use them instead:

$ cargo install lightmon
Arch AUR
$ yay -S lightmon


lightmon uses the GNU GPL v3.0 License


Icons made by Freepik from www.flaticon.com


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