# session_id

Source: https://libtmux.org/en/tmux/3.7c/catalog/formats/session_id/

> Unique session ID

format variable tmux3.7c

Unique session ID

* Scope

  Describes the session being formatted

* Type

  Text

* Usage

  `#{session_id}`

## Description[#](https://libtmux.org/en/tmux/3.7c/catalog/formats/session_id/#description)

Unique session ID

## Releases[#](https://libtmux.org/en/tmux/3.7c/catalog/formats/session_id/#releases)

* [tmux 3.7c](https://libtmux.org/en/tmux/3.7c/catalog/formats/session_id/) : present
* [tmux 3.2a](https://libtmux.org/en/tmux/3.2a/catalog/formats/session_id/) : present

## Source[#](https://libtmux.org/en/tmux/3.7c/catalog/formats/session_id/#source)

* Defined in

  [`format.c:3611`](https://github.com/tmux/tmux/blob/e476c1230b958df0cb12977517d24b3dc931375b/format.c#L3611)

* C source reference

  [`format_cb_session_id`](https://libtmux.org/en/tmux/3.7c/reference/c-function-format-c-format_cb_session_id/)

* CLI Manual

  [Original manual entry](https://libtmux.org/en/tmux/3.7c/manual/full/#session_id)

## Used by[#](https://libtmux.org/en/tmux/3.7c/catalog/formats/session_id/#used-by)

Library documentation that names this format variable.

* Python

  [`libtmux_mcp.tools.pane_tools.find_pane_by_position`](https://libtmux.org/en/py/latest/mcp/reference/libtmux_mcp-tools-pane_tools-find_pane_by_position/), [`libtmux_mcp.tools.session_tools.get_session_info`](https://libtmux.org/en/py/latest/mcp/reference/libtmux_mcp-tools-session_tools-get_session_info/), [`libtmux_mcp.tools.session_tools.list_windows`](https://libtmux.org/en/py/latest/mcp/reference/libtmux_mcp-tools-session_tools-list_windows/), [`libtmux_mcp.tools.window_tools.get_window_info`](https://libtmux.org/en/py/latest/mcp/reference/libtmux_mcp-tools-window_tools-get_window_info/), [`libtmux._internal.env.socket_path_from_env`](https://libtmux.org/en/py/latest/reference/libtmux-_internal-env-socket_path_from_env/), [`libtmux._internal.env.TMUX`](https://libtmux.org/en/py/latest/reference/libtmux-_internal-env-tmux/) and 15 more

* Ruby

  [`LibTmux::EntityRef#session_id`](https://libtmux.org/en/ruby/latest/reference/libtmux-entityref-session_id/)

* Rust

  [`client.Client.attached_session`](https://libtmux.org/en/rs/latest/reference/client-client-attached_session/), [`server.Server.from_env`](https://libtmux.org/en/rs/latest/reference/server-server-from_env/), [`target.escape_format`](https://libtmux.org/en/rs/latest/reference/target-escape_format/)

* Go

  [`tmux.FormatValues.SessionID`](https://libtmux.org/en/go/latest/reference/tmux-formatvalues-sessionid/)

* Java

  [`io.github.libtmux.SnapshotCapture.oneSession`](https://libtmux.org/en/java/latest/reference/io-github-libtmux-snapshotcapture-snapshotcapture-onesession/)