# LibTmux::Pane#send_keys

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/dcc9f8b5a6970144a9e7d80cd5f381d8f6198372/gems/libtmux/lib/libtmux/entity.rb#L199
- **Page:** https://libtmux.org/en/ruby/v0.1.0.alpha.2/reference/libtmux-pane-send_keys/

tmux command: [`send-keys`](/en/tmux/latest/manual/send-keys/)

```
def send_keys: (
  *::String,
  ?timeout: ::Numeric,
  ?cancel: untyped
) -> ::LibTmux::CommandResult
```

Behavior: Pane input and capture.

Behavior contract: Pane input and capture.

## Examples

Send a command to a shell, wait for its output notification, then capture the pane. Match a whole output line so the echoed command cannot satisfy the check. Use Ruby 4.0.7, Bundler, Git and tmux 3.2a 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 dcc9f8b5a6970144a9e7d80cd5f381d8f6198372
```

Save this dependency file as Gemfile:

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

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

Save this complete program as capture.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/dcc9f8b5a6970144a9e7d80cd5f381d8f6198372/examples/api/capture.rb).

```ruby
# frozen_string_literal: true

require "libtmux"

begin
  LibTmux::Server.start do |server|
    created = server.new_session(
      name: "capture", command: ["/bin/sh"],
      environment: {"ENV" => "/dev/null"}, receipt: true
    )
    pane = created.pane
    server.open_control(session: created.entity.ref) do |control|
      control.exchange("display-message -p ready", timeout: 1)
      output = control.subscribe(pane_id: pane.id, max_bytes: 8192, max_events: 32)
      pane.send_text("printf '\\nlibtmux capture ready\\n'")
      pane.send_keys("Enter")
      deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + 5
      bytes = "".b
      until bytes.lines(chomp: true).include?("libtmux capture ready")
        remaining = deadline - Process.clock_gettime(Process::CLOCK_MONOTONIC)
        raise "Output did not arrive within five seconds" unless remaining.positive?
        bytes << output.next(timeout: remaining).data
      end
      captured = pane.capture.stdout.lines(chomp: true)
      raise "Expected output is absent from the pane" unless captured.include?("libtmux capture ready")
      puts "libtmux capture ready"
    end
  end
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 capture.rb
```

Expected output:

```text
libtmux capture ready
```

## Raises

- `ArgumentError`

## In other ports

### Send keystrokes to a pane

- Python: [`libtmux.Pane.send_keys`](/en/py/latest/reference/libtmux-pane-send_keys/) (method)
- Lua: [`libtmux.Pane:send_keys`](/en/lua/latest/reference/libtmux-pane-send_keys/) (method)
- TypeScript: [`pane.Pane.sendKeys`](/en/ts/latest/reference/pane-pane-sendkeys/) (method)
- Rust: [`pane.Pane.send_keys`](/en/rs/latest/reference/pane-pane-send_keys/) (method)
- Go: [`tmux.Pane.SendKeys`](/en/go/latest/reference/tmux-pane-sendkeys/) (method)
- C#: [`LibTmux.Pane.SendKeysAsync`](/en/csharp/latest/reference/libtmux-pane-sendkeysasync/) (method)
- C++: [`libtmux::Pane::send_text`](/en/cxx/latest/reference/libtmux-pane-send_text/) (method)
- Swift: [`Server.sendKeys(_:to:literally:)`](/en/swift/latest/reference/server-sendkeys(_-to-literally-)/) (method)
- Kotlin: [`io.github.libtmux.kotlin.Pane.sendKeys`](/en/kotlin/latest/reference/io-github-libtmux-kotlin-pane-sendkeys/) (method)
- Scala: [`io.github.libtmux.scaladsl.Pane.sendKeys`](/en/scala/latest/reference/io-github-libtmux-scaladsl-pane-sendkeys/) (method)