---
title: "Tern Plugins: Turn Shell Output Into Native Views"
description: "Plugins for the Tern terminal that turn command output into tables, cards, and badges instead of raw text. who gives you a live session table; net renders whois, rdap, nmap, ss, and openssl x509 as structured views. MIT licensed."
pubDatetime: 2026-11-12T14:00:00Z
author: hrbrmstr
tags: ["tern", "terminal", "plugins", "lua", "developer-tools", "cli", "open-source"]
---
> Original: [Tern Plugins: Turn Shell Output Into Native Views](https://ai.rud.is/posts/2026-11-12-tern-plugins-native-views-for-shell-output)

---

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---

[Tern](https://stencil.so/tern) is a terminal that can do more than print text. With the **Native command output** setting on (it is on by default), a plugin can claim a command and replace its raw output with a real view: a table, a card, a set of badges. I wrote two plugins that do this for the shell commands I run every day. They are MIT licensed and live in one repo, `tern-plugins`.

Each folder in the repo is one plugin. You install only the ones you want.

| Folder | Plugin | Reads |
| --- | --- | --- |
| `who/` | Who | `w` |
| `net/` | Network Lookups | `whois`, `rdap`, `nmap`, `ss`, `openssl x509` |

## who: `w` as a session table

Run `w` and you get a table. The clock and uptime, the login count, and the three load averages sit at the top. Under them is one row per session: user, terminal, source, login time, idle time, CPU times, and the command that session is running.

Double-click a row to copy its command. Right-click for Copy user, Copy terminal, and Copy command.

Columns follow the header `w` prints, so `JCPU` and `PCPU` appear when the system has them.

## net: five network commands, five views

| Lens | View |
| --- | --- |
| `whois` | Domain and registrar up top, expiry with days left, statuses and name servers as lists, every other field in a table, the output's notices folded at the end |
| `rdap` | Registration from RDAP JSON: statuses, events with days left, registrar, name servers, DNSSEC |
| `nmap` | One section per host with latency and up/down, a port table with state dots and versions, the scan's notes |
| `ss` | Socket table: state, protocol, local and peer address, and the process holding the socket |
| `openssl x509` | Certificate card: subject, issuer, validity with days left, key size, signature algorithm, SANs |

`net` only reads output from programs you already run. It does not install `whois`, `nmap`, `ss`, or an RDAP client, and it adds no network calls of its own.

Here are some out examples for `whois`:

![](./img/whois.png)

and `rdap`:

![](./img/rdap.png)

## Requirements

- Tern 0.9 or newer for the full view. `who` also loads on 0.8.3 and 0.7.2, where it draws badges and a plain table instead of stat tiles and row menus.
- Settings › Terminal › **Native command output** on. This is the default.
- Shell integration on, so Tern sees each command line. Without it, no command gets a lens.

## Install

Clone the repo, then link the plugins you want. A linked plugin stays where it is and reloads when you save a file.

```sh
git clone https://rud.is/git/tern-plugins
tern plugin link tern-plugins/who
tern plugin link tern-plugins/net
```

To copy a plugin instead of linking it, use `tern plugin install tern-plugins/who`.

```sh
tern plugin list          # ready, or the load error
tern plugin unlink who    # stop using the linked folder
tern plugin remove who    # delete an installed copy
```

Remote hosts run their own Tern daemon with their own plugins. Install each plugin on every host that runs panes: `tern plugin dir` prints that host's plugin folder.

## How it works

A plugin is a folder with a `plugin.toml` and a `host.luau`. A lens claims command lines with globs in the manifest and is defined with `tern.lens.define` in Lua.

```text
who/
  plugin.toml    manifest: id, name, and the command lines each lens claims
  host.luau      the lens code
  README.md
net/
  plugin.toml
  host.luau      requires the lens files below
  common.luau    helpers the lenses share
  whois.luau     one file per lens
  rdap.luau
  nmap.luau
  ss.luau
  openssl.luau
```

When a lens cannot read a command's output, it returns nil and the block keeps the raw text. A form you did not plan for costs you nothing.

## Status

Early (very). Each lens matches only the command forms it can read. If a command form you rely on is missing, the lens returns nil and Tern keeps the raw text, so adding support is safe to try.

## License

MIT. Clone it, link it, and if a lens can read one more command you run, send the patch.


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