# LibTmux::Hooks#set

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/d8ce4bbee0ca7748a81929f81f7d8d07f8c51267/gems/libtmux/lib/libtmux/options.rb#L170
- **Page:** https://libtmux.org/en/ruby/v0.1.0.alpha.3/reference/libtmux-hooks-set/

tmux catalog: [Hooks](/en/tmux/latest/catalog/hooks/)

```
def set: (
  ::String,
  command: ::String,
  ?index: ::Integer?,
  ?append: bool,
  ?timeout: ::Numeric,
  ?cancel: untyped
) -> ::LibTmux::CommandResult
```

Behavior: Options and hooks.

Behavior contract: Options and hooks.

## Examples

Set and read a session option, convert its value to an Integer, and attach a hook command to the same session. Use Ruby 4.0.7, Bundler, Git and tmux 3.3a or newer on Unix, with /bin/cat and /bin/sh available. In an empty directory, fetch the documented library revision:

```console
$ git clone https://github.com/libtmux/libtmux-ruby.git libtmux-source && \
  git -C libtmux-source checkout d8ce4bbee0ca7748a81929f81f7d8d07f8c51267
```

Save this dependency file as Gemfile:

```ruby
source "https://rubygems.org"

gem "libtmux", path: "libtmux-source/gems/libtmux"
```

Save this complete program as options.rb. Its Server.start block owns a private tmux server and stops it on exit, including after an error.

[Source example](https://github.com/libtmux/libtmux-ruby/blob/d8ce4bbee0ca7748a81929f81f7d8d07f8c51267/examples/api/options.rb).

```ruby
# frozen_string_literal: true

begin
  # docs:begin main
  require "libtmux"

  LibTmux::Server.start do |server|
    session = server.new_session(name: "work", command: ["/bin/cat"])
    session.options.set("history-limit", 5000)
    limit = session.options.get("history-limit")
    puts "history-limit: #{limit.as(:integer)}"
    puts "inherited: #{limit.inherited?}"
    session.hooks.set("after-new-window", command: "display-message created")
    puts "hook: #{session.hooks.get('after-new-window').as(:string)}"
  end
  # docs:end main
rescue StandardError => error
  warn "#{error.class}: #{error.message}"
  exit 1
end
```

Install the runtime dependencies and run the saved program. An operation or cleanup error makes it exit unsuccessfully:

```console
$ bundle config set --local path vendor/bundle && \
  bundle install --jobs 2 && \
  bundle exec ruby options.rb
```

Expected output:

```text
history-limit: 5000
inherited: false
hook: display-message created
```

## Parameters

- `arg1` (`::String`)
- `command` (`::String`)
- `index` (`::Integer?`)
- `append` (`bool`)
- `timeout` (`::Numeric`)
- `cancel` (`untyped`)

## Raises

- `ArgumentError`