---
title: "The shell"
description: "bash is a complete bash shell running inside the engine, over this world's files and the engine's live state."
section: "Topics"
slug: "topics-bash"
canonical: "https://origozero.ai/docs/topics-bash"
updated: "2026-10-17T06:35:38.147946401+00:00"
---

# The shell

The shell runs in the engine, apart from the computer you are called from: everything it reads and writes is this world and this engine.

## Where things are

| Path | What it holds |
|------|---------------|
| `/zero/source` | The world's project, read and written in place. A file written here is a change to the world, picked up live. |
| `/zero/source/libs` | The libraries the world reads, `@builtin` among them. Reading one is the quickest way to learn how a thing is built. |
| `/zero/runtime` | The running engine's live state as files: cameras, physics, input, logs, jobs, the profiler and more. |
| `/zero/docs` | The engine's API reference: globals, components and tools. `man <topic>` reads it and the guides. |
| `/tmp` | Scratch space for the session, kept out of what the world saves, publishes and checks before play. It is the same directory as `/zero/source/tmp`. |
| `~` | Your home, `/zero/source/local`: kept on this machine for you, synced to no one, and likewise outside what the world publishes and checks before play. |

The shell starts in `/zero`.

## Programs

`ls /usr/bin` lists the installed programs, and `which` and `--help` answer as they do anywhere. A `command not found` means that one program is absent; do the job another ordinary way. `awk '{print NR": "$0}'` numbers lines where `nl` is missing, for example.

## The engine's own commands

- `zero` is the engine's command-line program: every operation the engine packages, grouped into toolboxes. Learn it as you would any unfamiliar CLI. `zero --help` shows every toolbox, `zero --search <query>` searches the tools and the documentation together, and `zero <toolbox> <tool> --help` shows one tool's arguments before you run it.
- `zm` is the world's version control, with the git verbs: `zm status`, `zm diff`, `zm add`, `zm commit -m`, `zm push`.
- `luau <file>` runs a Luau script inside the engine (`run <file>` is the same).
- `man <topic>` reads the documentation, and `man -k <word>` finds a page by name.

## Working the way you would anywhere

```sh
# Find where something is used
rg -n 'asset.resolve' /zero/source
find /zero/source -name '*.luau' | xargs grep -ln 'task.spawn'

# Count and summarise
find /zero/source -name '*.luau' | wc -l
find /zero/source -type f | sed 's/.*\.//' | sort | uniq -c

# Keep intermediate results in files
mkdir -p /tmp/work
rg -n 'TODO' /zero/source > /tmp/work/todo.txt
wc -l /tmp/work/todo.txt

# Look at the running engine
ls /zero/runtime
find /zero/runtime -maxdepth 2 -type d | head

# Find and run an engine operation
zero --search 'raycast'
zero camera --help

# Check in what you changed
zm status && zm add . && zm commit -m 'describe the change'
```