---
title: "vakna attach: watch a box's terminal, read-only"
description: "Watch a box's terminal, read-only; resumes it if suspended."
command: "vakna attach"
generated: scripts/generate.ts
verified:
  cli: "0.0.0-mock"
  date: "2026-10-20"
---

`vakna attach`: watch a box's terminal, read-only; resumes it if suspended. Proposed: the real CLI doesn't have this command yet.

## Synopsis

```sh
vakna attach <box>
```

## Flags

| Flag | Default | What it does |
| -- | -- | -- |
| `--format <format>` | `text` | text, or json: one JSON object per line |
| `--json` | `off` | the same as --format json |
| `-h, --help` | `off` | this help |

## Examples

### Example

```sh
$ vakna attach web
```

```prints
attached web · watching, read-only 0.09s
pnpm build… 61% [======    ]
:3000 listening
detached
```

Exit code 0.

### Another example

```sh
$ vakna attach web --format json
```

```prints
{"v":1,"event":"attached","box":"web","id":"sbx_eu1a_01JB81M3N4P5Q6R7S8T9V0W1X2","mode":"read-only","ms":90,"mocked":true}
{"v":1,"event":"job","box":"web","command":"pnpm build","pct":61,"mocked":true}
{"v":1,"event":"port","box":"web","port":3000,"state":"listening","mocked":true}
{"v":1,"event":"detached","box":"web","mocked":true}
```

Exit code 0.

### When it fails

```sh
$ vakna attach apj
```

```prints
vakna: no box "apj"
hint: vakna list  # did you mean api?
```

Exit code 1.

## Exit codes

| Code | Meaning |
| -- | -- |
| 0 | ok |
| 1 | vakna failed; under shell, run, try or fork, the command in the box failed |
| 2 | usage: a missing argument, an unknown flag or command |

## JSON output

With `--format json` (or `--json`) every line is one JSON object. `v` is the format's version; `mocked` marks numbers from the mock.

```sh
$ vakna attach web --format json
```

```prints
{"v":1,"event":"attached","box":"web","id":"sbx_eu1a_01JB81M3N4P5Q6R7S8T9V0W1X2","mode":"read-only","ms":90,"mocked":true}
{"v":1,"event":"job","box":"web","command":"pnpm build","pct":61,"mocked":true}
{"v":1,"event":"port","box":"web","port":3000,"state":"listening","mocked":true}
{"v":1,"event":"detached","box":"web","mocked":true}
```

## Errors

- [`vakna: unknown command, unknown flag or missing argument`](https://vakna.com/docs/errors/usage): Run `vakna <command> --help` and fix the command line it points to.
- [`vakna: no box "<box>"`](https://vakna.com/docs/errors/not_found): Run `vakna list` and use a name from it.
- [`vakna: "<id>" matches more than one box`](https://vakna.com/docs/errors/ambiguous): Use the box's name or its full id; `vakna list` shows both.

## --help

This page and the help text come from one definition.

```prints
vakna attach · watch a box's terminal, read-only; resumes it if suspended
Proposed: the real CLI doesn't have this command yet.

usage
  vakna attach <box>

flags
  --format <format>  text, or json: one JSON object per line  (default: text)
  --json             the same as --format json  (default: off)
  -h, --help         this help  (default: off)

examples
  vakna attach web
  vakna attach web --format json

exit codes
  0  ok
  1  vakna failed; under shell, run, try or fork, the command in the box failed
  2  usage: a missing argument, an unknown flag or command
```