# LibTmux::EntityRef#session_id

- **Module:** LibTmux::EntityRef#
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/c6d9d21771828e583692ca899ed817f9640d6a55/gems/libtmux/lib/libtmux/entity.rb#L22
- **Page:** https://libtmux.org/en/ruby/latest/reference/libtmux-entityref-session_id/

```
LibTmux::EntityRef#session_id() -> ::String?
```

Returns the value of attribute session_id.

Behavior contract: Entity references.