# The .bsh language


# The .bsh language

The third part of banish is a small scripting runtime. A `.bsh` file declares
verbs, filters, and config in plain directives. Drop one in `~/.banish/ext` and
your change is live with no recompile.

## Verbs

A verb is a named command shortcut. It can take arguments and expand into a real
command:

```bsh
!verb kpods
!args ns
!expand exec kubectl get pods -n {ns} -o wide
!help "List pods in namespace"
```

`!args` names the parameters, `{ns}` interpolates them, and `!help` is the
description shown to your agent.

## Filters

A filter matches a command and pipes its raw output through a shell one-liner that
strips the noise:

```bsh
!filter docker-build
!match docker build
!compact "grep -v '^Sending build' | grep -v '^---> ' | tail -20"
```

`!match` is a substring match against the command. `!compact` receives raw stdout
on stdin and writes the compact version to stdout. Keep the one-liner simple:
reach for `grep`, `sed`, `head`, `tail`, `cut`, and `awk` before anything heavier.

## Config

A `!config` block sets runtime options for the file:

```bsh
!config
!timeout "60s"
!output json
```

## Where files live

- Built-in filters are embedded in the binary, one `.bsh` file per ecosystem.
- Your own extensions go in `~/.banish/ext`. Every file there is loaded at startup.
- A project can ship a `BANISH` file in its root for repo-specific verbs.

See [built-in filters](/docs/reference/built-in-filters) for the full directive
list and the ecosystems banish ships with.