# tmux set-option

Source: https://libtmux.org/en/tmux/3.7c/manual/set-option/

> Set a pane option with -p, a window option with -w, a server option with -s, otherwise a session option.

Set a pane option with -p, a window option with -w, a server option with -s, otherwise a session option.

## Syntax

```tmux-usage
tmux set-option [-aFgopqsuUw] [-t target-pane] option [value]
```

Alias: `set`.

## Behavior

Set a pane option with `-p`, a window option with `-w`, a server option with `-s`, otherwise a session option. If the option is not a user option, `-w` or `-s` may be unnecessary - `tmux` will infer the scope from the option name, assuming `-w` for pane options. If `-g` is given, the global session or window option is set.

`-F` expands formats in the option value. The `-u` flag unsets an option, so a session inherits the option from the global options (or with `-g`, restores a global option to the default). `-U` unsets an option (like `-u`) but if the option is a pane option also unsets the option on any panes in the window. `value` depends on the option and its type and can be omitted for flag and choice options to toggle its value (choice options toggle between the first two choices).

The `-o` flag prevents setting an option that is already set and the `-q` flag suppresses errors about unknown or ambiguous options.

With `-a`, and if the option expects a string or a style, `value` is appended to the existing setting. For example:

```tmux-config
set -g status-left "foo"
set -ag status-left "bar"
```

Will result in ‘`foobar`’. And:

```tmux-config
set -g status-style "bg=red"
set -ag status-style "fg=blue"
```

Will result in a red background [*and*](https://libtmux.org/en/tmux/3.7c/manual/full/#and) blue foreground. Without `-a`, the result would be the default background and a blue foreground.

## Guides

* [Set options and hooks](https://libtmux.org/en/tmux/topics/options-and-hooks/)

## C implementation

Internal declarations in tmux 3.7c:

* [`cmd_set_option_entry`](https://libtmux.org/en/tmux/3.7c/reference/c-variable-cmd_set_option_entry/)
* [`cmd_set_option_exec`](https://libtmux.org/en/tmux/3.7c/reference/c-function-cmd-set-option-c-cmd_set_option_exec/)

tmux sources and license

Syntax comes from `tmux 3.7c list-commands`. See the [global options](https://libtmux.org/en/tmux/3.7c/manual/full/#DESCRIPTION) for sockets and configuration, and [command syntax and targets](https://libtmux.org/en/tmux/3.7c/manual/full/#COMMANDS).

Behavior is taken from the [tmux 3.7c manual](https://github.com/tmux/tmux/blob/79072dd1a9f5fb437a5859e362a496fd57ec0981/tmux.1).

[Command declaration](https://github.com/tmux/tmux/blob/79072dd1a9f5fb437a5859e362a496fd57ec0981/cmd-set-option.c#L36)

```
Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>

Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
```