# LibTmux::Server#snapshot

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/da7b6191b9439e3c84fa1c9eeaa9168263ee7af4/gems/libtmux/lib/libtmux/server.rb#L337
- **Page:** https://libtmux.org/en/ruby/v0.1.1/reference/libtmux-server-snapshot/

```
def snapshot: (
  ?timeout: ::Numeric,
  ?cancel: untyped,
  ?clients: bool,
  ?max_bytes: ::Integer,
  ?max_rows: ::Integer,
  ?max_field_bytes: ::Integer
) -> ::LibTmux::Snapshot
```

Behavior: Snapshot acquisition.

Behavior contract: Snapshot acquisition.

## Examples

Filter a captured snapshot, distinguish a missing session, and acquire a fresh pane selection. one raises unless exactly one record matches; one_or_nil returns nil only for zero matches. 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`:

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

gem "libtmux", "0.1.1"
```

Save this complete program as `query.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/da7b6191b9439e3c84fa1c9eeaa9168263ee7af4/examples/api/query.rb).

```ruby
# frozen_string_literal: true

begin
  # docs:begin main
  require "libtmux"

  LibTmux::Server.start do |server|
    work = server.new_session(name: "work", command: ["/bin/cat"], receipt: true)
    server.new_session(name: "logs", command: ["/bin/cat"])
    snapshot = server.snapshot
    session = snapshot.sessions.where(name: "work").one
    puts "matching session: #{session.name}"
    missing = snapshot.sessions.one_or_nil(name: "missing")
    puts "missing session: #{missing.nil?}"
    panes = server.search_panes(where: {id: work.pane.id})
    puts "matching pane: #{panes.one.id}"
  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:

```console
$ bundle install && \
  bundle exec ruby query.rb
```

Expected output:

```text
matching session: work
missing session: true
matching pane: %0
```

## Parameters

- `timeout` (`::Numeric`)
- `cancel` (`untyped`)
- `clients` (`bool`)
- `max_bytes` (`::Integer`)
- `max_rows` (`::Integer`)
- `max_field_bytes` (`::Integer`)

## tmux command

The tmux commands behind `snapshot`.

- [`list-clients`](/en/tmux/latest/manual/list-clients/)
- [`list-panes`](/en/tmux/latest/manual/list-panes/) `-a` server scope, [`cmd_list_panes_server`](/en/tmux/latest/reference/c-function-cmd-list-panes-c-cmd_list_panes_server/) (source: `gems/libtmux/lib/libtmux/capture.rb:93`)
- [`list-sessions`](/en/tmux/latest/manual/list-sessions/)
- [`list-windows`](/en/tmux/latest/manual/list-windows/) `-a` server scope, [`cmd_list_windows_exec`](/en/tmux/latest/reference/c-function-cmd-list-windows-c-cmd_list_windows_exec/) (source: `gems/libtmux/lib/libtmux/capture.rb:84`)

## tmux C API

The C declarations in tmux that implement these commands.

- [`cmd_list_clients_entry`](/en/tmux/latest/reference/c-variable-cmd_list_clients_entry/) (attribute)
- [`cmd_list_clients_exec`](/en/tmux/latest/reference/c-function-cmd-list-clients-c-cmd_list_clients_exec/) (function)
- [`cmd_list_panes_entry`](/en/tmux/latest/reference/c-variable-cmd_list_panes_entry/) (attribute)
- [`cmd_list_panes_server`](/en/tmux/latest/reference/c-function-cmd-list-panes-c-cmd_list_panes_server/) (function)
- [`cmd_list_sessions_entry`](/en/tmux/latest/reference/c-variable-cmd_list_sessions_entry/) (attribute)
- [`cmd_list_sessions_exec`](/en/tmux/latest/reference/c-function-cmd-list-sessions-c-cmd_list_sessions_exec/) (function)
- [`cmd_list_windows_entry`](/en/tmux/latest/reference/c-variable-cmd_list_windows_entry/) (attribute)
- [`cmd_list_windows_exec`](/en/tmux/latest/reference/c-function-cmd-list-windows-c-cmd_list_windows_exec/) (function)

## In other ports

Capture the tmux hierarchy

| Language | Equivalent |
| --- | --- |
| Python | no equivalent on `Server` |
| Lua | [`libtmux.Server:snapshot`](/en/lua/latest/reference/libtmux-server-snapshot/) (method) |
| PowerShell | [`LibTmux\Get-TmuxSnapshot`](/en/powershell/latest/reference/libtmux-get-tmuxsnapshot/) (cmdlet). Acquires a replacement `LibTmux.Server` to [`-Depth`](/en/powershell/latest/reference/libtmux-get-tmuxsnapshot/#LibTmux%5CGet-TmuxSnapshot.parameter.Depth) (panes by default). Acquisition is not atomic; retained handles do not refresh. |
| Julia | [`LibTmux.snapshot`](/en/julia/latest/reference/libtmux-snapshot-1gv6/) (function). Acquires a new `Snapshot` over an observation interval. Topology checks do not make it a transaction; earlier snapshots do not refresh. |
| Elixir | [`LibTmux.Server.snapshot/2`](/en/elixir/latest/reference/libtmux-server-snapshot-2/) (function). Captures a new graph over an observation interval. A retained `Snapshot` never refreshes. |
| TypeScript | [`server.Server.snapshot`](/en/ts/latest/reference/server-server-snapshot/) (method) |
| Rust | no equivalent on `Server` |
| Go | [`tmux.Server.Snapshot`](/en/go/latest/reference/tmux-server-snapshot/) (method) |
| Java | [`io.github.libtmux.Server.snapshot`](/en/java/latest/reference/io-github-libtmux-server-server-snapshot/) (method) |
| Kotlin | [`io.github.libtmux.kotlin.Server.snapshot`](/en/kotlin/latest/reference/io-github-libtmux-kotlin-server-snapshot/) (method) |
| Scala | [`io.github.libtmux.scaladsl.Server.snapshot`](/en/scala/latest/reference/io-github-libtmux-scaladsl-server-snapshot/) (method) |
| C# | [`LibTmux.Server.CaptureSnapshotAsync`](/en/csharp/latest/reference/libtmux-server-capturesnapshotasync/) (method) |
| F# | [`LibTmux.FSharp.Server.capture`](/en/fsharp/latest/reference/libtmux-fsharp-server-capture/) (function). Acquires a replacement shared .NET `LibTmux.Server` to the requested depth. Acquisition is not atomic; retained handles do not refresh. |
| C++ | no equivalent on `Server` |
| Swift | [`Server.snapshot()`](/en/swift/latest/reference/server-snapshot()/) (method) |