# Options and hooks

Source: https://libtmux.org/en/swift/latest/topics/options-and-hooks/

> Read and update tmux options, and register commands for tmux events.

Use options to change tmux behavior, such as [`automatic-rename`](https://libtmux.org/en/tmux/latest/catalog/options/automatic-rename/) or the
status-line format. Use hooks to run commands on events such as
[`session-renamed`](https://libtmux.org/en/tmux/latest/catalog/hooks/session-renamed/) or [`after-split-window`](https://libtmux.org/en/tmux/latest/catalog/hooks/after-split-window/). Choose the scope supported by the
option or hook.

## Reading and writing options

Read, set, or unset an option at its supported scope. Distinguish a local
override from the effective value inherited from a parent scope.

**Read all (this scope):** [`server.options(.pane(pane))`](<https://libtmux.org/en/swift/latest/reference/server-options(_-)/>)

**Read effective/inherited:** [`server.option(name, scope: .pane(pane))`](<https://libtmux.org/en/swift/latest/reference/server-option(_-scope-)/>) reads
presence from the listing, then the value with `-v`

**Set:** [`server.setOption(name, to: value, scope: .pane(pane))`](<https://libtmux.org/en/swift/latest/reference/server-setoption(_-to-scope-)/>)

**Unset:** [`server.unsetOption(name, scope: .pane(pane))`](<https://libtmux.org/en/swift/latest/reference/server-unsetoption(_-scope-)/>)

### Examples

After a successful write completes, read the option to obtain its updated value.
The following examples set, read, and unset an option:

```swift
try await server.setOption("automatic-rename", to: "off", scope: .pane(pane))
try await server.options(.pane(pane))
try await server.unsetOption("automatic-rename", scope: .pane(pane))
```

## Hooks

**Set:** [`server.setHook(name, to: command, at: index, in: scope)`](<https://libtmux.org/en/swift/latest/reference/server-sethook(_-to-at-in-)/>)

**Unset:** [`server.unsetHook(name, in: scope)`](<https://libtmux.org/en/swift/latest/reference/server-unsethook(_-in-)/>)

**List:** [`server.hooks(scope)`](<https://libtmux.org/en/swift/latest/reference/server-hooks(_-)/>)

**Run now, without the event:** [`server.runHook(name, in: scope)`](<https://libtmux.org/en/swift/latest/reference/server-runhook(_-in-)/>)

### Examples

tmux stores hook commands in indexed arrays, such as [`after-new-window[0]`](https://libtmux.org/en/tmux/latest/catalog/hooks/after-new-window/).

The `at:` parameter selects the array index.

Set and list a session hook. The next section explains window and pane scope
limitations:

```swift
try await server.setHook("session-renamed", to: "display-message 'renamed'", in: .session(session.id.rawValue))
try await server.hooks(.session(session.id.rawValue))
```

<a id="window-and-pane-hook-scopes-are-mostly-fiction"></a>

## Supported hook scopes

tmux stores hooks globally or per session. Accepted [`set-hook -w`](https://libtmux.org/en/tmux/latest/manual/set-hook/) or `-p` flags
do not imply a separate window or pane hook table, and [`show-hooks`](https://libtmux.org/en/tmux/latest/manual/show-hooks/) does not
provide a corresponding listing. Check the event's supported scope if a hook is
accepted but never fires.

[`HookScope`](<https://libtmux.org/en/swift/latest/reference/hookscope/>) restricts registration to `.global` and `.session`.

Options have window and pane tables of their own. The hook-scope limitation does
not apply to ordinary options.

## tmux version compatibility

Check the library's supported tmux versions before using a version-specific
option or hook.

<details>
<summary>tmux manual and source</summary>

The tmux manual defines [option scopes and inherited reads](https://github.com/tmux/tmux/blob/94796f6b1182507efac8a272fc309a79e22e58a5/tmux.1#L4725).
Unsetting a local value restores inheritance. Hook programs run in tmux when
their event occurs; see the [hook implementation](https://github.com/tmux/tmux/blob/94796f6b1182507efac8a272fc309a79e22e58a5/cmd-set-option.c).

</details>