Ever wonder how after npm install, you could use the installed tool on the command line, as if they were added to your bin?

For example, after installing mocha, you could run mocha on your command line directly.

This is a guide on how to do that.

Create the executable file

Firstly, say you have this superbot.js that uses commander.js that handles the command line options.

It is good practice to put such javascript in bin folder, so let’s assume that.

The first line of the file should also have a shebang, that tells terminal to run with node.

#!/usr/bin/env node

With that, you can run ./bin/superbot.js on the command line, instead of node ./bin/superbot.js.

Also make sure the javascript is executable permission eg chmod +x ./bin/superbot.js.

Add bin to package.json

Add a bin key to package.json like this:

"bin" : { "superbot" : "./bin/superbot.js" }

When someone does a npm install, npm will create a symlink from ./bin/superbot.js to their /usr/local/bin/superbot.

That’s why right after install, they can run commands such as:

$ superbot --powerup somefile.txt

But if you are the developer, and you try to run any command, it will not work, yet. You need to run:

npm link

This will explicitly create the symlink.

That’s it!

PS: Another good (but longer) guide to build a CLI utility from Jonathan Fielding using: grunt-init, commander.js and underscore.js .