# tmux new-window

Source: https://libtmux.org/en/tmux/3.7c/manual/new-window/

> Create a new window.

Create a new window.

## Syntax

```tmux-usage
tmux new-window [-abdkPS] [-c start-directory] [-e environment] [-F format] [-n window-name] [-t target-window] [shell-command [argument ...]]
```

Alias: `neww`.

## Behavior

Create a new window. With `-a` or `-b`, the new window is inserted at the next index after or before the specified `target-window`, moving windows up if necessary; otherwise `target-window` is the new window location.

If `-d` is given, the session does not make the new window the current window. `target-window` represents the window to be created; if the target already exists an error is shown, unless the `-k` flag is used, in which case it is destroyed. If `-S` is given and a window named `window-name` already exists, it is selected (unless `-d` is also given in which case the command does nothing).

`shell-command` is the command to execute. If `shell-command` is not specified, the value of the `default-command` option is used. `-c` specifies the working directory in which the new window is created.

When the shell command completes, the window closes. See the `remain-on-exit` option to change this behaviour.

`-e` takes the form ‘`VARIABLE=value`’ and sets an environment variable for the newly created window; it may be specified multiple times.

The `TERM` environment variable must be set to ‘`screen`’ or ‘`tmux`’ for all programs running [*inside*](https://libtmux.org/en/tmux/3.7c/manual/full/#inside) `tmux`. New windows will automatically have ‘`TERM=screen`’ added to their environment, but care must be taken not to reset this in shell startup files or by the `-e` option.

The `-P` option prints information about the new window after it has been created. By default, it uses the format ‘`#{session_name}:#{window_index}`’ but a different format may be specified with `-F`.

## Guides

* [Test with an isolated server](https://libtmux.org/en/tmux/guides/testing-with-libtmux/)

## C implementation

Internal declarations in tmux 3.7c:

* [`cmd_new_window_entry`](https://libtmux.org/en/tmux/3.7c/reference/c-variable-cmd_new_window_entry/)
* [`cmd_new_window_exec`](https://libtmux.org/en/tmux/3.7c/reference/c-function-cmd-new-window-c-cmd_new_window_exec/)

## Use from a library

Each API describes its own defaults, errors and execution model.

* [Scala](https://libtmux.org/en/scala/latest/reference/io-github-libtmux-scaladsl-session-newwindow/)
* [Kotlin](https://libtmux.org/en/kotlin/latest/reference/io-github-libtmux-kotlin-session-newwindow/)
* [Python](https://libtmux.org/en/py/latest/reference/libtmux-session-new_window/)
* [TypeScript](https://libtmux.org/en/ts/latest/reference/session-session-newwindow/)
* [Rust](https://libtmux.org/en/rs/latest/reference/session-session-new_window/)
* [Go](https://libtmux.org/en/go/latest/reference/tmux-session-newwindow/)
* [Java](https://libtmux.org/en/java/latest/reference/io-github-libtmux-session-session-newwindow/)
* [C#](https://libtmux.org/en/csharp/latest/reference/libtmux-session-createwindowasync/)
* [C++](https://libtmux.org/en/cxx/latest/reference/libtmux-session-new_window/)
* [Swift](https://libtmux.org/en/swift/latest/reference/server-newwindow\(in-named-startdirectory-\)/)
* [Ruby](https://libtmux.org/en/ruby/latest/reference/libtmux-session-new_window/)
* [Lua](https://libtmux.org/en/lua/latest/reference/libtmux-session-new_window/)

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-new-window.c#L38)

```
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.
```