# Launching programs in new windows/tabs

kitty has a `launch` action that can be used to run arbitrary programs in new windows/tabs. It can be mapped to user defined shortcuts in kitty.conf. It is very powerful and allows sending the contents of the current window to the launched program, as well as many other options.

In the simplest form, you can use it to open a new kitty window running the shell, as shown below:

    map f1 launch

To run a different program simply pass the command line as arguments to launch:

    map f1 launch vim path/to/some/file

To open a new window with the same working directory as the currently active window:

    map f1 launch --cwd=current

To open the new window in a new tab:

    map f1 launch --type=tab

To pass the contents of the current screen and scrollback to the started process:

    map f1 launch --stdin-source=@screen_scrollback less

There are many more powerful options, refer to the complete list below.

## The piping environment

When using `launch --stdin-source`, the program to which the data is piped has a special environment variable declared, `KITTY_PIPE_DATA` whose contents are:

    KITTY_PIPE_DATA={scrolled_by}:{cursor_x},{cursor_y}:{lines},{columns}

where `scrolled_by` is the number of lines kitty is currently scrolled by, `cursor_(x|y)` is the position of the cursor on the screen with `(1,1)` being the top left corner and `{lines},{columns}` being the number of rows and columns of the screen.

## Special arguments

There are a few special placeholder arguments that can be specified as part of the command line. Namely `@selection` which is replaced by the current selection and `@active-kitty-window-id` which is replaced by the id of the currently active kitty window. For example:

    map f1 launch my-program @active-kitty-window-id

## Watching launched windows

The `launch --watcher` option allows you to specify python functions that will be called at specific events, such as when the window is resized or closed. Simply specify the path to a python module that specifies callback functions for the events you are interested in, for example:

    def on_resize(boss, window, data):
        # Here data will contain old_geometry and new_geometry

    def on_close(boss, window, data):
        # called when window is closed, typically when the program running in
        # it exits.

Every callback is passed a reference to the global `Boss` object as well as the `Window` object the action is occurring on. The `data` object is mapping that contains event dependent data. Some useful methods and attributes for the `Window` object are: `as_text(as_ans=False, add_history=False, add_wrap_markers=False, alternate_screen=False)` with which you can get the contents of the window and its scrollback buffer. Similarly, `window.child.pid` is the PID of the processes that was launched in the window and `window.id` is the internal kitty `id` of the window.

## Syntax reference

    launch [options] [program-to-run ...]

Launch an arbitrary program in a new kitty window/tab. Note that if you specify a program-to-run you can use the special placeholder `@selection` which will be replaced by the current selection.

### Options

`--title``<WINDOW_TITLE>``,` `--window-title``<WINDOW_TITLE>`

  The title to set for the new window. By default, title is controlled by the child process.

`--tab-title``<TAB_TITLE>`

  The title for the new tab if launching in a new tab. By default, the title of the active window in the tab is used as the tab title.

`--type``<TYPE>`

  Where to launch the child process, in a new kitty window in the current tab, a new tab, or a new OS window or an overlay over the current window. Note that if the current window already has an overlay, then it will open a new window. The value of background means the process will be run in the background. The values clipboard and primary are meant to work with `launch --stdin-source` to copy data to the system clipboard or primary selection. Default: `window` Choices: `background, clipboard, os-window, overlay, primary, tab, window`

`--keep-focus```

  Keep the focus on the currently active window instead of switching to the newly opened window.

`--cwd``<CWD>`

  The working directory for the newly launched child. Use the special value `current` to use the working directory of the currently active window.

`--env``<ENV>`

  Environment variables to set in the child process. Can be specified multiple times to set different environment variables. Syntax: name=value.

`--copy-colors```

  Set the colors of the newly created window to be the same as the colors in the currently active window.

`--copy-cmdline```

  Ignore any specified command line and instead use the command line from the currently active window.

`--copy-env```

  Copy the environment variables from the currently active window into the newly launched child process.

`--location``<LOCATION>`

  Where to place the newly created window when it is added to a tab which already has existing windows in it. `after` and `before` place the new window before or after the active window. `neighbor` is a synonym for `after`. Also applies to creating a new tab, where the value of `after` will cause the new tab to be placed next to the current tab instead of at the end. The values of `vsplit` and `hsplit` are only used by the `splits` layout and control if the new window is placed in a vertical or horizontal split with the currently active window. The default is to place the window in a layout dependent manner, typically, after the currently active window. Default: `default` Choices: `after, before, default, first, hsplit, last, neighbor, vsplit`

`--allow-remote-control```

  Programs running in this window can control kitty (if remote control is enabled). Note that any program with the right level of permissions can still write to the pipes of any other program on the same computer and therefore can control kitty. It can, however, be useful to block programs running on other computers (for example, over ssh) or as other users.

`--stdin-source``<STDIN_SOURCE>`

  Pass the screen contents as `STDIN` to the child process. @selection is the currently selected text. @screen is the contents of the currently active window. @screen_scrollback is the same as @screen, but includes the scrollback buffer as well. @alternate is the secondary screen of the current active window. For example if you run a full screen terminal application, the secondary screen will be the screen you return to when quitting the application. Default: `none` Choices: `@alternate, @alternate_scrollback, @screen, @screen_scrollback, @selection, none`

`--stdin-add-formatting```

  When using `launch --stdin-source` add formatting escape codes, without this only plain text will be sent.

`--stdin-add-line-wrap-markers```

  When using `launch --stdin-source` add a carriage return at every line wrap location (where long lines are wrapped at screen edges). This is useful if you want to pipe to program that wants to duplicate the screen layout of the screen.

`--marker``<MARKER>`

  Create a marker that highlights text in the newly created window. The syntax is the same as for the `toggle_marker` map action (see Marks).

`--os-window-class``<OS_WINDOW_CLASS>`

  Set the WM_CLASS property on X11 and the application id property on Wayland for the newly created OS Window when using `launch --type``=os-window`. Defaults to whatever is used by the parent kitty process, which in turn defaults to `kitty`.

`--os-window-name``<OS_WINDOW_NAME>`

  Set the WM_NAME property on X11 for the newly created OS Window when using `launch --type``=os-window`. Defaults to `launch --os-window-class`.

`--watcher``<WATCHER>``,` `-w``<WATCHER>`

  Path to a python file. Appropriately named functions in this file will be called for various events, such as when the window is resized or closed. See the section on watchers in the launch command documentation Launching programs in new windows/tabs. Relative paths are resolved relative to the kitty config directory.