parseargs

This is a utility script to aid with parsing command line arguments in other scripts.

Installation

npm install --global @benkenawell/parseargs

You could also clone the repo and run npm link which should make it available anywhere you have that version of node as "parseargs"

You could also just copy index.js and link to it somewhere on your PATH. I recommend giving it the name "parseargs", but that's up to you. I would not call it getopt or getopts, those are already executable names.

Usage

This package is meant to be used as a script/executable, primarily in your shell. There is nothing to import.

parseargs --option test=string,t --no-strict -- "$@" | jq .

parseargs --config "$(parseargs --option test=string,t --no-strict)" -- "$@" | jq .

# headers formatting
parseargs --option test=string --positional --format headers -- --test one two three

#!/usr/bin/env bash
# An example script calling parseargs.
# Takes the --test, -t flag and is not strict

config="$(jq -n '
  {
    "options": {
      "test": {"type": "string", "short": "t"}
    },
    "strict": false
  }
')"

# parses the args to this script. Pretty prints with jq
parseargs --config "$config" -- "$@" | jq .

Requirements

Node, of course. parseArgs was made stable in v20.16 and v22.4, so any version newer than that should work. In v16 and v18 it was still experimental, so it might work sometimes but I'm not supporting it. If you need to manage your node versions, I recommend mise

Bun or Deno might work. If you try it, let me know how it goes in an Issue.

Background

I know Node well. Node has a solid utility function, parseArgs for parsing arguments from the command line. I often write bash scripts where I want to have some of that parsing power.

Node is also very good at the JSON format. jq is a command line utility that is also very good at parsing json. If we combine these JSON parsing functions, we can use JSON as an interchange format in the terminal.

Is it a great idea? I'm not sure! JSON is still text in the strict sense of the word, but does it fit the Unix philosophy? I'm not sure! But with jq I can parse through the returned arguments now a lot faster than I can remember awk.

I do really like the Unix philosophy though, so this tool may move to conform better over time. Hopefully the --format headers flag is an example of that. awk isn't that hard if you have an easy format to parse.

It'd also be cool to take something from stdin. The arguments make the most sense, but I rely on node's process.argv for the right quoting of your argument list lol. I could take the config, but now the --format flag would still need passed on the cmdline.

Who is this for?

Me, primarily. But if you want to use it too, please go ahead. I would love to learn that other people have this same problem.

Have an issue with my script? Please open an issue.

I doubt my little script is going to be the fastest way to parse arguments like this, I'm only after a simple way to parse out command line options for further processing.