+++
title = "Shell"
description = "The firmware's own commands, typed on the device: look at its state, the SD card, the radio and the network with no PC and no cable."
weight = 9
[extra]
tag = "Shell"
+++

The firmware has a set of **commands**, made for working on it from a PC. The Shell runs them **on the device itself**: no computer, no cable, no Wi-Fi. It is the tool for the day something is wrong and you are nowhere near a desk.

It can do real damage: `rm` deletes, `reboot` restarts, `debug on` opens the device to the network. It is the same trust as holding the device, and nothing more.

## Using it

Type a command and press <kbd>Enter</kbd>. `help` lists them all; the [command reference](/dev/debug/commands/) says what each does. A few to start with:

| Command | Shows |
|---|---|
| `info` | The firmware's version, uptime, memory, Wi-Fi, the SD card and both firmware slots |
| `wifi status` | The network, the address, and where the DNS and time servers came from |
| `ls /notes` | A folder of the SD card, with sizes and dates |
| `crash` | The last crash, if there was one |
| `update check` | Whether a newer release exists |
| `lora status` | What the radio is set to and what it has heard |

- <kbd>Tab</kbd> **completes** the command's name. If several fit, it lists them.
- <kbd>Fn</kbd> with up and down brings back **lines you typed before**.
- <kbd>Alt</kbd> with up and down **scrolls back** through what was printed.
- `clear` empties the screen, and `quit` (or Back) leaves.

## What you see

**The replies to your own commands, and nothing else.** The firmware prints a lot besides: IRC connecting, a packet received, whatever a PC on the USB port or the Debug Console is asking for. None of that reaches the Shell. The firmware knows who each line is printed for, so an answer that comes a moment later from another part of it (a folder listing, `tasks`) is still yours.

<kbd>Ctrl</kbd> + <kbd>b</kbd> shows **everything** the firmware prints instead, and `all` shows in the corner. Press it again to go back.

## Opening an App

Type an App's name **with a capital letter** to open it, without going back to the Launcher:

`Irc`  `Wifi`  `Gnss`  `Gemini`  `Lora`  `Storage`  `Notes`  `System`  `Settings`

The capital is the difference: every command is in small letters, every App starts with a capital. <kbd>Tab</kbd> completes them too.

## Deleting

`rm` works as it does on Unix, with one addition: it asks.

| You type | What happens |
|---|---|
| `rm /notes/a.txt` | Asks, then deletes the file |
| `rm -f /notes/a.txt` | Deletes it without asking |
| `rm /captures/old` | Refused: it is a folder, and a folder needs `-r` |
| `rm -r /captures/old` | Removed at once if it is empty. If not, asks first |
| `rm -rf /captures/old` | Removed with everything in it, without asking |

The folders the firmware keeps its own files in can't be removed, as in the [Storage App](/guide/storage/).

## Screenshots

```
screenshot        the screen, now
screenshot 5      the screen in 5 seconds: time to go to another App
```

The picture is saved as a PNG in `/screenshots` on the SD card, named by date and time, and a Toast says so once it is written (so the Toast is never in the picture). From the Shell, "now" is always a picture of the Shell: use the pause to get to the screen you want. The [Storage App](/guide/storage/) shows the files; to look at them, take the card to a computer.

## What it costs

Nothing while it is closed. Open, about 7 KB of memory, given back when you leave: with IRC connected and a Gemini page open, that can be the difference (see [the memory limit](/howto/not-enough-memory/)).

## The keys, as the device lists them

What <kbd>Fn</kbd> + <kbd>h</kbd> shows on this screen. This table is generated from the firmware's own lists, so it is always the current one.

{{ keys(scopes=["shell"]) }}