How to design a CLI

Vercel’s a got a great system for deploying serverless JS web apps. It Just Works(TM). Vercel’s CLI however…is a learning example. We’ll go over some of their interesting and noteworthy design choices, and then, describe what other option we could take.

Write by default to stderr

People use CLIs because they’re cheap on bandwidth, RAM, CPU, and don’t have images. It certainly has nothing to do with UNIX’s rich set of tools and composability.

$ vercel ls | grep https
Vercel CLI 28.4.10
> Deployments for [REDACTED] under [REDACTED] [366ms]
> To list deployments for a project, run `vercel ls [project]`.

  Age     Deployment                        Status      Duration
  5m      https://[REDACTED].vercel.app     ● Ready     17s
  57m     https://[REDACTED].vercel.app     ● Ready     17s

But Only do it for some part of one help message

$ vercel inspect --help | grep ls
Vercel CLI 28.4.10
$

Being inconsist…