# libtmux.common.EnvironmentMixin.set_environment

- **Module:** libtmux.common.EnvironmentMixin
- **Package:** libtmux
- **Language:** Python
- **Kind:** method
- **Source:** https://github.com/tmux-python/libtmux/blob/9fdd083a8181a827889337b63cd4e6daea661a8c/src/libtmux/common.py#L64
- **Page:** https://libtmux.org/en/py/latest/reference/libtmux-common-environmentmixin-set_environment/

```
libtmux.common.EnvironmentMixin.set_environment(self, name: str, value: str, expand_format: bool | None = None, hidden: bool | None = None) -> None
```

Set environment ``$ tmux set-environment <name> <value>``.

## Parameters

- `self`
- `name` (str): The environment variable name, e.g. 'PATH'.
- `value` (str): Environment value.
- `expand_format` (bool | None): Expand tmux format strings in the value (``-F`` flag).
- `hidden` (bool | None): Mark the variable as hidden (``-h`` flag).

## Raises

- `ValueError`: If tmux returns an error.