Ruby API

method libtmux-ruby v0.1.1

Pane.capture

Behavior: Pane input and capture.

Source and package

Qualified name: LibTmux::Pane#capture
Module: LibTmux
Declared in: Pane
Package: libtmux
Source: gems/libtmux/lib/libtmux/entity.rb
Other languages: PowerShell Julia Elixir PythonLuaTypeScriptRustGoJavaC#C++SwiftKotlinScalaF#

def capture: ( ?start: ::Integer | ::String | nil, ?finish: ::Integer | ::String | nil, ?join: bool, ?escapes: bool, ?escape_bytes: bool, ?preserve_trailing: bool, ?trim_trailing: bool, ?alternate: bool, ?mode_screen: bool, ?pending: bool, ?timeout: ::Numeric, ?cancel: untyped ) -> ::LibTmux::CommandResult method libtmux [source] ¶

Description#

Behavior contract: Pane input and capture.

Examples#

Send a command to a shell, poll the pane until its output line appears, then capture it. Match a whole output line so the echoed command cannot satisfy the check. Use Ruby 3.3 or newer with Bundler, and tmux 3.3a or newer, on Unix with /bin/cat and /bin/sh available. In an empty directory, save this Gemfile:

source "https://rubygems.org"

gem "libtmux", "0.1.1"

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. View source

# frozen_string_literal: true

begin
  # docs:begin main
  require "libtmux"

  LibTmux::Server.start do |server|
    created = server.new_session(
      name: "capture", command: ["/bin/sh"],
      environment: {"ENV" => "/dev/null"}, receipt: true
    )
    pane = created.pane
    pane.send_text("printf '\\nlibtmux capture ready\\n'")
    pane.send_keys("Enter")
    deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + 5
    captured = pane.capture.stdout.lines(chomp: true)
    until captured.include?("libtmux capture ready")
      raise "Output did not arrive within five seconds" if Process.clock_gettime(Process::CLOCK_MONOTONIC) > deadline
      sleep 0.05
      captured = pane.capture.stdout.lines(chomp: true)
    end
    raise "Expected output is absent from the pane" unless captured.include?("libtmux capture ready")
    puts "libtmux capture ready"
  end
  # docs:end main
rescue StandardError => error
  warn "#{error.class}: #{error.message}"
  exit 1
end

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

$ bundle install && \
  bundle exec ruby capture.rb

Expected output:

libtmux capture ready

Parameters

start (::Integer | ::String | nil) #
finish (::Integer | ::String | nil) #
join (bool) #
escapes (bool) #
escape_bytes (bool) #
preserve_trailing (bool) #
trim_trailing (bool) #
alternate (bool) #
mode_screen (bool) #
pending (bool) #
timeout (::Numeric) #
cancel (untyped) #

tmux command#

The tmux commands behind capture.

capture-pane

tmux C API#

The C declarations in tmux that implement these commands.

cmd_capture_pane_entry cmd_capture_pane_exec

Guides#

Pages that discuss capture.

Guides: Server bindings
Mcp: MCP server guide

In other ports#

Read a pane’s visible contents

Equivalents of Read a pane’s visible contents in other languages
Language	Equivalent
Python	`libtmux.Pane.capture_pane`
Lua	`libtmux.Pane:capture`
TypeScript	`pane.Pane.capture`
Rust	`pane.Pane.capture`
Go	`tmux.Pane.Capture`
Java	`io.github.libtmux.Pane.capture`
Kotlin	`io.github.libtmux.kotlin.Pane.capture`
Scala	`io.github.libtmux.scaladsl.Pane.capture`
C#	`LibTmux.Pane.CaptureAsync`
F#	`LibTmux.FSharp.Pane.capture`
C++	`libtmux::Pane::capture`
Swift	`Server.capture(_:includingHistory:)`

No equivalent is recorded in PowerShell, Julia or Elixir.

Scripting & web

Compiled & native

JVM

.NET

BEAM

tmux

Pane.capture

Description#

Examples#

tmux command#

tmux C API#

Guides#

In other ports#

Description#

Examples#

tmux command#

tmux C API#

Guides#

In other ports#

Related types#