Write a pkg.yaml

A package is a single pkg.yaml manifest stored at pkgs/<name>/pkg.yaml inside a catalog. It tells nem how to fetch, verify, install, and test a tool.

Here’s a complete manifest for jq:

schemaVersion: 1
name: jq
description: Command-line JSON processor
homepage: https://jqlang.github.io/jq/
license: MIT

archive:
  fetch:
    github_release:
      repo: jqlang/jq
      assetName: "jq-{{.OS}}-{{.Arch}}"
      templateOverrides:
        darwin: macos
      releaseFilter: '^jq-(\d+\.\d+\.\d+)$'
      versionTemplate: "v{{.Capture}}"
      releaseTemplate: 'jq-{{.Version | trimPrefix "v"}}'
  verify:
    checksumGitHubAsset: "sha256sum.txt"   # algorithm: sha256 by default

install:
  - copy:
      from: "{{.Archive}}"
      to: "{{.InstallDir}}/bin/jq"

test:
  - run:
      cmd: ["{{.InstallDir}}/bin/jq", "--version"]

The top-level blocks:

• Metadata — schemaVersion, name, description, homepage, license.
• archive — how to fetch the artifact and verify its checksum. This one uses the github_release fetcher; nem also supports github_tag, http, and oci.
• install — an ordered list of steps (copy, extract, run, …) that place files under {{.InstallDir}}.
• test — optional commands run after install to confirm it worked.

Strings are Go templates with variables like {{.OS}}, {{.Arch}}, {{.Version}}, {{.Archive}}, and {{.InstallDir}}, plus helpers such as trimPrefix.

The pkg.yaml schema reference documents every field, fetch block, verify mode, install step, and template variable. When you’re done, validate it.