# Options and hooks

Source: https://libtmux.org/en/java/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):** [`pane.options().all()`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-options/>)

**Read effective/inherited:** [`pane.options().get(name)`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-options/>) reads [`show-options -A
-v`](https://libtmux.org/en/tmux/latest/manual/show-options/): inherited, not just local

**Set:** [`pane.options().set(name, value)`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-options/>)

**Unset:** [`pane.options().unset(name)`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-options/>)

### Examples

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

```java
pane.options().set("automatic-rename", "off");
pane.options().all();
pane.options().unset("automatic-rename");
```

## Hooks

**Set:** [`pane.hooks().set(event, command)`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-hooks/>), `.append(event, command)`

**Unset:** [`pane.hooks().unset(event)`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-hooks/>)

**List:** [`pane.hooks().all()`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-hooks/>)

**Run now, without the event:** [`pane.hooks().run(event)`](<https://libtmux.org/en/java/latest/reference/io-github-libtmux-pane-pane-hooks/>): tmux's [`set-hook -R`](https://libtmux.org/en/tmux/latest/manual/set-hook/)

### 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/).

Use `.append()` to add a command without choosing the next array index.

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

```java
session.hooks().set("session-renamed", "display-message 'renamed'");
session.hooks().all();
```

<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.

Check `hooks().all()` when diagnosing a hook that does not fire. tmux can accept
a hook at an unsupported scope without an effective registration.

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>