The launch command#

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 run multiple commands in a shell, use:

map f1 launch sh -c "ls && exec zsh"

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.

Note

To avoid duplicating launch actions with frequently used parameters, you can use action_alias to define launch action aliases. For example:

action_alias launch_tab launch --cwd=current --type=tab
map f1 launch_tab vim
map f2 launch_tab emacs

The F1 key will now open vim in a new tab with the current windows working directory.

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:

@selection: Replaced by the currently selected text.
@active-kitty-window-id: Replaced by the id of the currently active kitty window.
@line-count: Replaced by the number of lines in STDIN. Only present when passing some data to STDIN.
@input-line-number: Replaced by the number of lines a pager should scroll to match the current scroll position in kitty. See scrollback_pager for details.
@scrolled-by: Replaced by the number of lines kitty is currently scrolled by.
@cursor-x: Replaced by the current cursor x position with 1 being the leftmost cell.
@cursor-y: Replaced by the current cursor y position with 1 being the topmost cell.
@first-line-on-screen: Replaced by the first line on screen. Can be used for pager positioning.
@last-line-on-screen: Replaced by the last line on screen. Can be used for pager positioning.

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:

from typing import Any, Dict

from kitty.boss import Boss
from kitty.window import Window


def on_resize(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # Here data will contain old_geometry and new_geometry

def on_focus_change(boss: Boss, window: Window, data: Dict[str, Any])-> None:
    # Here data will contain focused

def on_close(boss: Boss, window: Window, data: Dict[str, Any])-> None:
    # called when window is closed, typically when the program running in
    # it exits

def on_set_user_var(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # called when a "user variable" is set or deleted on a window. Here
    # data will contain key and value

def on_title_change(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # called when the window title is changed on a window. Here
    # data will contain title and from_child. from_child will be True
    # when a title change was requested via escape code from the program
    # running in the terminal

def on_cmd_startstop(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # called when the shell starts/stops executing a command. Here
    # data will contain is_start and time.

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 a dict 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.

Finding executables#

When you specify a command to run as just a name rather than an absolute path, it is searched for in the system-wide PATH environment variable. Note that this may not be the value of PATH inside a shell, as shell startup scripts often change the value of this variable. If it is not found there, then a system specific list of default paths is searched. If it is still not found, then your shell is run and the value of PATH inside the shell is used.

See exe_search_path for details and how to control this.

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. The special value current will copy the title from the currently active window.

--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. The special value current will copy the title from the title of the currently active tab.

--type <TYPE>#

Where to launch the child process:

window: A new kitty window in the current tab
tab: A new tab in the current OS window
os-window: A new operating system window
overlay: An overlay window covering the current active kitty window
overlay-main: An overlay window covering the current active kitty window. Unlike a plain overlay window, this window is considered as a main window which means it is used as the active window for getting the current working directory, the input text for kittens, launch commands, etc. Useful if this overlay is intended to run for a long time as a primary window.
background: The process will be run in the background, without a kitty window. Note that if kitten @ launch --allow-remote-control is specified the KITTY_LISTEN_ON environment variable will be set to a dedicated socket pair file descriptor that the process can use for remote control.
clipboard, primary: These two are meant to work with --stdin-source to copy data to the system clipboard or primary selection.

Default: window Choices: background, clipboard, os-window, overlay, overlay-main, primary, tab, window

--dont-take-focus, --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. The special value last_reported uses the last working directory reported by the shell (needs Shell integration to work). The special value oldest works like current but uses the working directory of the oldest foreground process associated with the currently active window rather than the newest foreground process. Finally, the special value root refers to the process that was originally started when the window was created.

--env <ENV>#: Environment variables to set in the child process. Can be specified multiple times to set different environment variables. Syntax: name=value. Using name= will set to empty string and just name will remove the environment variable.

--var <VAR>#: User variables to set in the created window. Can be specified multiple times to set different user variables. Syntax: name=value. Using name= will set to empty string.

--hold#: Keep the window open even after the command being executed exits, at a shell prompt.

--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. Note that this only copies the environment when the window was first created, as it is not possible to get updated environment variables from arbitrary processes. To copy that environment, use either the clone-in-kitty feature or the kitty remote control feature with kitten @ launch --copy-env.

--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, hsplit and split are only used by the splits layout and control if the new window is placed in a vertical, horizontal or automatic 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, split, vsplit

--allow-remote-control#: Programs running in this window can control kitty (even if remote control is not enabled in kitty.conf). 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. See --remote-control-password for ways to restrict actions allowed by remote control.

--remote-control-password <REMOTE_CONTROL_PASSWORD>#

Restrict the actions remote control is allowed to take. This works like remote_control_password. You can specify a password and list of actions just as for remote_control_password. For example:

--remote-control-password '"my passphrase" get-* set-colors'

This password will be in effect for this window only. Note that any passwords you have defined for remote_control_password in kitty.conf are also in effect. You can override them by using the same password here. You can also disable all remote_control_password global passwords for this window, by using:

--remote-control-password '!'

This option only takes effect if --allow-remote-control is also specified. Can be specified multiple times to create multiple passwords. This option was added to kitty in version 0.26.0

--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.
@first_cmd_output_on_screen: is the output from the first command run in the shell on screen.
@last_cmd_output: is the output from the last command run in the shell.
@last_visited_cmd_output: is the first output below the last scrolled position via scroll_to_prompt, this needs shell integration to work.

Default: none Choices: @alternate, @alternate_scrollback, @first_cmd_output_on_screen, @last_cmd_output, @last_visited_cmd_output, @screen, @screen_scrollback, @selection, none

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

--stdin-add-line-wrap-markers#: When using --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 action (see Mark text on screen).

--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 --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 --type=os-window. Defaults to --os-window-class.

--os-window-title <OS_WINDOW_TITLE>#: Set the title for the newly created OS window. This title will override any titles set by programs running in kitty. The special value current will use the title of the current OS window, if any.

--os-window-state <OS_WINDOW_STATE>#: The initial state for the newly created OS Window. Default: normal Choices: fullscreen, maximized, minimized, normal

--logo <LOGO>#: Path to a PNG image to use as the logo for the newly created window. See window_logo_path. Relative paths are resolved from the kitty configuration directory.

--logo-position <LOGO_POSITION>#: The position for the window logo. Only takes effect if --logo is specified. See window_logo_position.

--logo-alpha <LOGO_ALPHA>#: The amount the window logo should be faded into the background. Only takes effect if --logo is specified. See window_logo_alpha. Default: -1

--color <COLOR>#

Change colors in the newly launched window. You can either specify a path to a .conf file with the same syntax as kitty.conf to read the colors from, or specify them individually, for example:

--color background=white --color foreground=red

--spacing <SPACING>#: Set the margin and padding for the newly created window. For example: margin=20 or padding-left=10 or margin-h=30. The shorthand form sets all values, the *-h and *-v variants set horizontal and vertical values. Can be specified multiple times. Note that this is ignored for overlay windows as these use the settings from the base window.

--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, focused or closed. See the section on watchers in the launch command documentation: Watching launched windows. Relative paths are resolved relative to the kitty config directory. Global watchers for all windows can be specified with watcher in kitty.conf.