Configuring kitty — kitty 0.18.3 documentation

# Configuring kitty

kitty is highly customizable, everything from keyboard shortcuts, to painting frames-per-second. See below for an overview of all customization possibilities.

You can open the config file within kitty by pressing `ctrl+shift+f2`. You can also display the current configuration by running `kitty --debug-config`.

kitty looks for a config file in the OS config directories (usually `~/.config/kitty/kitty.conf`) but you can pass a specific path via the `kitty --config` option or use the `KITTY_CONFIG_DIRECTORY` environment variable. See the `kitty --config` option for full details.

Comments can be added to the config file as lines starting with the `#` character. This works only if the `#` character is the first character in the line.

You can include secondary config files via the `include` directive. If you use a relative path for include, it is resolved with respect to the location of the current config file. Note that environment variables are expanded, so `${USER}.conf` becomes `name.conf` if `USER=name`. For example:

    include other.conf

## Fonts

kitty has very powerful font management. You can configure individual font faces and even specify special fonts for particular characters.

`font_family``,` `bold_font``,` `italic_font``,` `bold_italic_font`

    font_family      monospace
    bold_font        auto
    italic_font      auto
    bold_italic_font auto

You can specify different fonts for the bold/italic/bold-italic variants. To get a full list of supported fonts use the kitty list-fonts command. By default they are derived automatically, by the OSes font system. Setting them manually is useful for font families that have many weight variants like Book, Medium, Thick, etc. For example:

    font_family      Operator Mono Book
    bold_font        Operator Mono Medium
    italic_font      Operator Mono Book Italic
    bold_italic_font Operator Mono Medium Italic

`font_size`

    font_size 11.0

Font size (in pts)

`force_ltr`

    force_ltr no

kitty does not support BIDI (bidirectional text), however, for RTL scripts, words are automatically displayed in RTL. That is to say, in an RTL script, the words “HELLO WORLD” display in kitty as “WORLD HELLO”, and if you try to select a substring of an RTL-shaped string, you will get the character that would be there had the the string been LTR. For example, assuming the Hebrew word ירושלים, selecting the character that on the screen appears to be ם actually writes into the selection buffer the character י.

kitty’s default behavior is useful in conjunction with a filter to reverse the word order, however, if you wish to manipulate RTL glyphs, it can be very challenging to work with, so this option is provided to turn it off. Furthermore, this option can be used with the command line program GNU FriBidi to get BIDI support, because it will force kitty to always treat the text as LTR, which FriBidi expects for terminals.

`adjust_line_height``,` `adjust_column_width`

    adjust_line_height  0
    adjust_column_width 0

Change the size of each character cell kitty renders. You can use either numbers, which are interpreted as pixels or percentages (number followed by %), which are interpreted as percentages of the unmodified values. You can use negative pixels or percentages less than 100% to reduce sizes (but this might cause rendering artifacts).

`symbol_map`

    symbol_map U+E0A0-U+E0A3,U+E0C0-U+E0C7 PowerlineSymbols

Map the specified unicode codepoints to a particular font. Useful if you need special rendering for some symbols, such as for Powerline. Avoids the need for patched fonts. Each unicode code point is specified in the form `U+<code point in hexadecimal>`. You can specify multiple code points, separated by commas and ranges separated by hyphens. `symbol_map` itself can be specified multiple times. Syntax is:

    symbol_map codepoints Font Family Name

`disable_ligatures`

    disable_ligatures never

Choose how you want to handle multi-character ligatures. The default is to always render them. You can tell kitty to not render them when the cursor is over them by using `cursor` to make editing easier, or have kitty never render them at all by using `always`, if you don’t like them. The ligature strategy can be set per-window either using the kitty remote control facility or by defining shortcuts for it in kitty.conf, for example:

    map alt+1 disable_ligatures_in active always
    map alt+2 disable_ligatures_in all never
    map alt+3 disable_ligatures_in tab cursor

Note that this refers to programming ligatures, typically implemented using the `calt` OpenType feature. For disabling general ligatures, use the `font_features` setting.

`font_features`

    font_features none

Choose exactly which OpenType features to enable or disable. This is useful as some fonts might have features worthwhile in a terminal. For example, Fira Code Retina includes a discretionary feature, `zero`, which in that font changes the appearance of the zero (0), to make it more easily distinguishable from Ø. Fira Code Retina also includes other discretionary features known as Stylistic Sets which have the tags `ss01` through `ss20`.

Note that this code is indexed by PostScript name, and not the font family. This allows you to define very precise feature settings; e.g. you can disable a feature in the italic font but not in the regular font.

To get the PostScript name for a font, use `kitty + list-fonts --psnames`:

    $ kitty + list-fonts --psnames | grep Fira
    Fira Code
    Fira Code Bold (FiraCode-Bold)
    Fira Code Light (FiraCode-Light)
    Fira Code Medium (FiraCode-Medium)
    Fira Code Regular (FiraCode-Regular)
    Fira Code Retina (FiraCode-Retina)

The part in brackets is the PostScript name.

Enable alternate zero and oldstyle numerals:

    font_features FiraCode-Retina +zero +onum

Enable only alternate zero:

    font_features FiraCode-Retina +zero

Disable the normal ligatures, but keep the `calt` feature which (in this font) breaks up monotony:

    font_features TT2020StyleB-Regular -liga +calt

In conjunction with `force_ltr`, you may want to disable Arabic shaping entirely, and only look at their isolated forms if they show up in a document. You can do this with e.g.:

    font_features UnifontMedium +isol -medi -fina -init

`box_drawing_scale`

    box_drawing_scale 0.001, 1, 1.5, 2

Change the sizes of the lines used for the box drawing unicode characters These values are in pts. They will be scaled by the monitor DPI to arrive at a pixel value. There must be four values corresponding to thin, normal, thick, and very thick lines.

## Cursor customization

`cursor`

    cursor #cccccc

Default cursor color

`cursor_text_color`

    cursor_text_color #111111

Choose the color of text under the cursor. If you want it rendered with the background color of the cell underneath instead, use the special keyword: background

`cursor_shape`

    cursor_shape block

The cursor shape can be one of (block, beam, underline)

`cursor_beam_thickness`

    cursor_beam_thickness 1.5

Defines the thickness of the beam cursor (in pts)

`cursor_underline_thickness`

    cursor_underline_thickness 2.0

Defines the thickness of the underline cursor (in pts)

`cursor_blink_interval`

    cursor_blink_interval -1

The interval (in seconds) at which to blink the cursor. Set to zero to disable blinking. Negative values mean use system default. Note that numbers smaller than `repaint_delay` will be limited to `repaint_delay`.

`cursor_stop_blinking_after`

    cursor_stop_blinking_after 15.0

Stop blinking cursor after the specified number of seconds of keyboard inactivity. Set to zero to never stop blinking.

## Scrollback

`scrollback_lines`

    scrollback_lines 2000

Number of lines of history to keep in memory for scrolling back. Memory is allocated on demand. Negative numbers are (effectively) infinite scrollback. Note that using very large scrollback is not recommended as it can slow down resizing of the terminal and also use large amounts of RAM.

`scrollback_pager`

    scrollback_pager less --chop-long-lines --RAW-CONTROL-CHARS +INPUT_LINE_NUMBER

Program with which to view scrollback in a new window. The scrollback buffer is passed as STDIN to this program. If you change it, make sure the program you use can handle ANSI escape sequences for colors and text formatting. INPUT_LINE_NUMBER in the command line above will be replaced by an integer representing which line should be at the top of the screen. Similarly CURSOR_LINE and CURSOR_COLUMN will be replaced by the current cursor position.

`scrollback_pager_history_size`

    scrollback_pager_history_size 0

Separate scrollback history size, used only for browsing the scrollback buffer (in MB). This separate buffer is not available for interactive scrolling but will be piped to the pager program when viewing scrollback buffer in a separate window. The current implementation stores one character in 4 bytes, so approximatively 2500 lines per megabyte at 100 chars per line. A value of zero or less disables this feature. The maximum allowed size is 4GB.

`wheel_scroll_multiplier`

    wheel_scroll_multiplier 5.0

Modify the amount scrolled by the mouse wheel. Note this is only used for low precision scrolling devices, not for high precision scrolling on platforms such as macOS and Wayland. Use negative numbers to change scroll direction.

`touch_scroll_multiplier`

    touch_scroll_multiplier 1.0

Modify the amount scrolled by a touchpad. Note this is only used for high precision scrolling devices on platforms such as macOS and Wayland. Use negative numbers to change scroll direction.

## Mouse

`mouse_hide_wait`

    mouse_hide_wait 3.0

Hide mouse cursor after the specified number of seconds of the mouse not being used. Set to zero to disable mouse cursor hiding. Set to a negative value to hide the mouse cursor immediately when typing text. Disabled by default on macOS as getting it to work robustly with the ever-changing sea of bugs that is Cocoa is too much effort.

`url_color``,` `url_style`

    url_color #0087bd
    url_style curly

The color and style for highlighting URLs on mouse-over. `url_style` can be one of: none, single, double, curly

`open_url_modifiers`

    open_url_modifiers kitty_mod

The modifier keys to press when clicking with the mouse on URLs to open the URL

`open_url_with`

    open_url_with default

The program with which to open URLs that are clicked on. The special value `default` means to use the operating system’s default URL handler.

`url_prefixes`

    url_prefixes http https file ftp

The set of URL prefixes to look for when detecting a URL under the mouse cursor.

`copy_on_select`

    copy_on_select no

Copy to clipboard or a private buffer on select. With this set to `clipboard`, simply selecting text with the mouse will cause the text to be copied to clipboard. Useful on platforms such as macOS that do not have the concept of primary selections. You can instead specify a name such as `a1` to copy to a private kitty buffer instead. Map a shortcut with the `paste_from_buffer` action to paste from this private buffer. For example:

    map cmd+shift+v paste_from_buffer a1

Note that copying to the clipboard is a security risk, as all programs, including websites open in your browser can read the contents of the system clipboard.

`strip_trailing_spaces`

    strip_trailing_spaces never

Remove spaces at the end of lines when copying to clipboard. A value of `smart` will do it when using normal selections, but not rectangle selections. `always` will always do it.

`rectangle_select_modifiers`

    rectangle_select_modifiers ctrl+alt

The modifiers to use rectangular selection (i.e. to select text in a rectangular block with the mouse)

`terminal_select_modifiers`

    terminal_select_modifiers shift

The modifiers to override mouse selection even when a terminal application has grabbed the mouse

`select_by_word_characters`

    select_by_word_characters @-./_~?&=%+#

Characters considered part of a word when double clicking. In addition to these characters any character that is marked as an alphanumeric character in the unicode database will be matched.

`click_interval`

    click_interval -1.0

The interval between successive clicks to detect double/triple clicks (in seconds). Negative numbers will use the system default instead, if available, or fallback to 0.5.

`focus_follows_mouse`

    focus_follows_mouse no

Set the active window to the window under the mouse when moving the mouse around

`pointer_shape_when_grabbed`

    pointer_shape_when_grabbed arrow

The shape of the mouse pointer when the program running in the terminal grabs the mouse. Valid values are: `arrow`, `beam` and `hand`

## Performance tuning

`repaint_delay`

    repaint_delay 10

Delay (in milliseconds) between screen updates. Decreasing it, increases frames-per-second (FPS) at the cost of more CPU usage. The default value yields ~100 FPS which is more than sufficient for most uses. Note that to actually achieve 100 FPS you have to either set `sync_to_monitor` to no or use a monitor with a high refresh rate. Also, to minimize latency when there is pending input to be processed, repaint_delay is ignored.

`input_delay`

    input_delay 3

Delay (in milliseconds) before input from the program running in the terminal is processed. Note that decreasing it will increase responsiveness, but also increase CPU usage and might cause flicker in full screen programs that redraw the entire screen on each loop, because kitty is so fast that partial screen updates will be drawn.

`sync_to_monitor`

    sync_to_monitor yes

Sync screen updates to the refresh rate of the monitor. This prevents tearing (https://en.wikipedia.org/wiki/Screen_tearing) when scrolling. However, it limits the rendering speed to the refresh rate of your monitor. With a very high speed mouse/high keyboard repeat rate, you may notice some slight input latency. If so, set this to no.

## Terminal bell

`enable_audio_bell`

    enable_audio_bell yes

Enable/disable the audio bell. Useful in environments that require silence.

`visual_bell_duration`

    visual_bell_duration 0.0

Visual bell duration. Flash the screen when a bell occurs for the specified number of seconds. Set to zero to disable.

`window_alert_on_bell`

    window_alert_on_bell yes

Request window attention on bell. Makes the dock icon bounce on macOS or the taskbar flash on linux.

`bell_on_tab`

    bell_on_tab yes

Show a bell symbol on the tab if a bell occurs in one of the windows in the tab and the window is not the currently focused window

`command_on_bell`

    command_on_bell none

Program to run when a bell occurs.

## Window layout

`remember_window_size``,` `initial_window_width``,` `initial_window_height`

    remember_window_size  yes
    initial_window_width  640
    initial_window_height 400

If enabled, the window size will be remembered so that new instances of kitty will have the same size as the previous instance. If disabled, the window will initially have size configured by initial_window_width/height, in pixels. You can use a suffix of “c” on the width/height values to have them interpreted as number of cells instead of pixels.

`enabled_layouts`

    enabled_layouts *

The enabled window layouts. A comma separated list of layout names. The special value `all` means all layouts. The first listed layout will be used as the startup layout. Default configuration is all layouts in alphabetical order. For a list of available layouts, see the Layouts.

`window_resize_step_cells``,` `window_resize_step_lines`

    window_resize_step_cells 2
    window_resize_step_lines 2

The step size (in units of cell width/cell height) to use when resizing windows. The cells value is used for horizontal resizing and the lines value for vertical resizing.

`window_border_width`

    window_border_width 1.0

The width (in pts) of window borders. Will be rounded to the nearest number of pixels based on screen resolution. Note that borders are displayed only when more than one window is visible. They are meant to separate multiple windows.

`draw_minimal_borders`

    draw_minimal_borders yes

Draw only the minimum borders needed. This means that only the minimum needed borders for inactive windows are drawn. That is only the borders that separate the inactive window from a neighbor. Note that setting a non-zero window margin overrides this and causes all borders to be drawn.

`window_margin_width`

    window_margin_width 0

The window margin (in pts) (blank area outside the border). A single value sets all four sides. Two values set the vertical and horizontal sides. Three values set top, horizontal and bottom. Four values set top, right, bottom and left.

`single_window_margin_width`

    single_window_margin_width -1

The window margin (in pts) to use when only a single window is visible. Negative values will cause the value of `window_margin_width` to be used instead. A single value sets all four sides. Two values set the vertical and horizontal sides. Three values set top, horizontal and bottom. Four values set top, right, bottom and left.

`window_padding_width`

    window_padding_width 0

The window padding (in pts) (blank area between the text and the window border). A single value sets all four sides. Two values set the vertical and horizontal sides. Three values set top, horizontal and bottom. Four values set top, right, bottom and left.

`placement_strategy`

    placement_strategy center

When the window size is not an exact multiple of the cell size, the cell area of the terminal window will have some extra padding on the sides. You can control how that padding is distributed with this option. Using a value of `center` means the cell area will be placed centrally. A value of `top-left` means the padding will be on only the bottom and right edges.

`active_border_color`

    active_border_color #00ff00

The color for the border of the active window. Set this to none to not draw borders around the active window.

`inactive_border_color`

    inactive_border_color #cccccc

The color for the border of inactive windows

`bell_border_color`

    bell_border_color #ff5a00

The color for the border of inactive windows in which a bell has occurred

`inactive_text_alpha`

    inactive_text_alpha 1.0

Fade the text in inactive windows by the specified amount (a number between zero and one, with zero being fully faded).

`hide_window_decorations`

    hide_window_decorations no

Hide the window decorations (title-bar and window borders) with `yes`. On macOS, `titlebar-only` can be used to only hide the titlebar. Whether this works and exactly what effect it has depends on the window manager/operating system.

`resize_debounce_time`

    resize_debounce_time 0.1

The time (in seconds) to wait before redrawing the screen when a resize event is received. On platforms such as macOS, where the operating system sends events corresponding to the start and end of a resize, this number is ignored.

`resize_draw_strategy`

    resize_draw_strategy static

Choose how kitty draws a window while a resize is in progress. A value of `static` means draw the current window contents, mostly unchanged. A value of `scale` means draw the current window contents scaled. A value of `blank` means draw a blank window. A value of `size` means show the window size in cells.

`resize_in_steps`

    resize_in_steps no

Resize the OS window in steps as large as the cells, instead of with the usual pixel accuracy. Combined with an `initial_window_width` and `initial_window_height` in number of cells, this option can be used to keep the margins as small as possible when resizing the OS window. Note that this does not currently work on Wayland.

`confirm_os_window_close`

    confirm_os_window_close 0

Ask for confirmation when closing an OS window or a tab that has at least this number of kitty windows in it. A value of zero disables confirmation. This confirmation also applies to requests to quit the entire application (all OS windows, via the quit action).

## Tab bar

`tab_bar_edge`

    tab_bar_edge bottom

Which edge to show the tab bar on, top or bottom

`tab_bar_margin_width`

    tab_bar_margin_width 0.0

The margin to the left and right of the tab bar (in pts)

`tab_bar_style`

    tab_bar_style fade

The tab bar style, can be one of: `fade`, `separator`, `powerline`, or `hidden`. In the fade style, each tab’s edges fade into the background color, in the separator style, tabs are separated by a configurable separator, and the powerline shows the tabs as a continuous line.

`tab_bar_min_tabs`

    tab_bar_min_tabs 2

The minimum number of tabs that must exist before the tab bar is shown

`tab_switch_strategy`

    tab_switch_strategy previous

The algorithm to use when switching to a tab when the current tab is closed. The default of `previous` will switch to the last used tab. A value of `left` will switch to the tab to the left of the closed tab. A value of `last` will switch to the right-most tab.

`tab_fade`

    tab_fade 0.25 0.5 0.75 1

Control how each tab fades into the background when using `fade` for the `tab_bar_style`. Each number is an alpha (between zero and one) that controls how much the corresponding cell fades into the background, with zero being no fade and one being full fade. You can change the number of cells used by adding/removing entries to this list.

`tab_separator`

    tab_separator " ┇"

The separator between tabs in the tab bar when using `separator` as the `tab_bar_style`.

`tab_title_template`

    tab_title_template "{title}"

A template to render the tab title. The default just renders the title. If you wish to include the tab-index as well, use something like: `{index}: {title}`. Useful if you have shortcuts mapped for `goto_tab N`. In addition you can use `{layout_name}` for the current layout name and `{num_windows}` for the number of windows in the tab. Note that formatting is done by Python’s string formatting machinery, so you can use, for instance, `{layout_name[:2].upper()}` to show only the first two letters of the layout name, upper-cased.

`active_tab_title_template`

    active_tab_title_template none

Template to use for active tabs, if not specified falls back to `tab_title_template`.

`active_tab_foreground``,` `active_tab_background``,` `active_tab_font_style``,` `inactive_tab_foreground``,` `inactive_tab_background``,` `inactive_tab_font_style`

    active_tab_foreground   #000
    active_tab_background   #eee
    active_tab_font_style   bold-italic
    inactive_tab_foreground #444
    inactive_tab_background #999
    inactive_tab_font_style normal

Tab bar colors and styles

`tab_bar_background`

    tab_bar_background none

Background color for the tab bar. Defaults to using the terminal background color.

## Color scheme

`foreground``,` `background`

    foreground #dddddd
    background #000000

The foreground and background colors

`background_opacity`

    background_opacity 1.0

The opacity of the background. A number between 0 and 1, where 1 is opaque and 0 is fully transparent. This will only work if supported by the OS (for instance, when using a compositor under X11). Note that it only sets the background color’s opacity in cells that have the same background color as the default terminal background. This is so that things like the status bar in vim, powerline prompts, etc. still look good. But it means that if you use a color theme with a background color in your editor, it will not be rendered as transparent. Instead you should change the default background color in your kitty config and not use a background color in the editor color scheme. Or use the escape codes to set the terminals default colors in a shell script to launch your editor. Be aware that using a value less than 1.0 is a (possibly significant) performance hit. If you want to dynamically change transparency of windows set `dynamic_background_opacity` to `yes` (this is off by default as it has a performance cost)

`background_image`

    background_image none

Path to a background image. Must be in PNG format.

`background_image_layout`

    background_image_layout tiled

Whether to tile or scale the background image.

`background_image_linear`

    background_image_linear no

When background image is scaled, whether linear interpolation should be used.

`dynamic_background_opacity`

    dynamic_background_opacity no

Allow changing of the `background_opacity` dynamically, using either keyboard shortcuts (`ctrl+shift+a>m` and `ctrl+shift+a>l`) or the remote control facility.

`background_tint`

    background_tint 0.0

How much to tint the background image by the background color. The tint is applied only under the text area, not margin/borders. Makes it easier to read the text. Tinting is done using the current background color for each window. This setting applies only if `background_opacity` is set and transparent windows are supported or `background_image` is set.

`dim_opacity`

    dim_opacity 0.75

How much to dim text that has the DIM/FAINT attribute set. One means no dimming and zero means fully dimmed (i.e. invisible).

`selection_foreground`

    selection_foreground #000000

The foreground for text selected with the mouse. A value of none means to leave the color unchanged.

`selection_background`

    selection_background #fffacd

The background for text selected with the mouse.

### The color table

The 16 terminal colors. There are 8 basic colors, each color has a dull and bright version. You can also set the remaining colors from the 256 color table as color16 to color255.

`color0``,` `color8`

    color0 #000000
    color8 #767676

black

`color1``,` `color9`

    color1 #cc0403
    color9 #f2201f

red

`color2``,` `color10`

    color2  #19cb00
    color10 #23fd00

green

`color3``,` `color11`

    color3  #cecb00
    color11 #fffd00

yellow

`color4``,` `color12`

    color4  #0d73cc
    color12 #1a8fff

blue

`color5``,` `color13`

    color5  #cb1ed1
    color13 #fd28ff

magenta

`color6``,` `color14`

    color6  #0dcdcd
    color14 #14ffff

cyan

`color7``,` `color15`

    color7  #dddddd
    color15 #ffffff

white

`mark1_foreground`

    mark1_foreground black

Color for marks of type 1

`mark1_background`

    mark1_background #98d3cb

Color for marks of type 1 (light steel blue)

`mark2_foreground`

    mark2_foreground black

Color for marks of type 2

`mark2_background`

    mark2_background #f2dcd3

Color for marks of type 1 (beige)

`mark3_foreground`

    mark3_foreground black

Color for marks of type 3

`mark3_background`

    mark3_background #f274bc

Color for marks of type 1 (violet)

## Advanced

`shell`

    shell .

The shell program to execute. The default value of . means to use whatever shell is set as the default shell for the current user. Note that on macOS if you change this, you might need to add `--login` to ensure that the shell starts in interactive mode and reads its startup rc files.

`editor`

    editor .

The console editor to use when editing the kitty config file or similar tasks. A value of . means to use the environment variables VISUAL and EDITOR in that order. Note that this environment variable has to be set not just in your shell startup scripts but system-wide, otherwise kitty will not see it.

`close_on_child_death`

    close_on_child_death no

Close the window when the child process (shell) exits. If no (the default), the terminal will remain open when the child exits as long as there are still processes outputting to the terminal (for example disowned or backgrounded processes). If yes, the window will close as soon as the child process exits. Note that setting it to yes means that any background processes still using the terminal can fail silently because their stdout/stderr/stdin no longer work.

`allow_remote_control`

    allow_remote_control no

Allow other programs to control kitty. If you turn this on other programs can control all aspects of kitty, including sending text to kitty windows, opening new windows, closing windows, reading the content of windows, etc. Note that this even works over ssh connections. You can chose to either allow any program running within kitty to control it, with `yes` or only programs that connect to the socket specified with the `kitty --listen-on` command line option, if you use the value `socket-only`. The latter is useful if you want to prevent programs running on a remote computer over ssh from controlling kitty.

`listen_on`

    listen_on none

Tell kitty to listen to the specified unix/tcp socket for remote control connections. Note that this will apply to all kitty instances. It can be overridden by the `kitty --listen-on` command line flag. This option accepts only UNIX sockets, such as unix:${TEMP}/mykitty or (on Linux) unix:@mykitty. Environment variables are expanded. If {kitty_pid} is present then it is replaced by the PID of the kitty process, otherwise the PID of the kitty process is appended to the value, with a hyphen. This option is ignored unless you also set `allow_remote_control` to enable remote control. See the help for `kitty --listen-on` for more details.

`env`

    env

Specify environment variables to set in all child processes. Note that environment variables are expanded recursively, so if you use:

    env MYVAR1=a
    env MYVAR2=${MYVAR1}/${HOME}/b

The value of MYVAR2 will be `a/<path to home directory>/b`.

`update_check_interval`

    update_check_interval 24

Periodically check if an update to kitty is available. If an update is found a system notification is displayed informing you of the available update. The default is to check every 24 hrs, set to zero to disable.

`startup_session`

    startup_session none

Path to a session file to use for all kitty instances. Can be overridden by using the `kitty --session` command line option for individual instances. See Startup Sessions in the kitty documentation for details. Note that relative paths are interpreted with respect to the kitty config directory. Environment variables in the path are expanded.

`clipboard_control`

    clipboard_control write-clipboard write-primary

Allow programs running in kitty to read and write from the clipboard. You can control exactly which actions are allowed. The set of possible actions is: write-clipboard read-clipboard write-primary read-primary. You can additionally specify no-append to disable kitty’s protocol extension for clipboard concatenation. The default is to allow writing to the clipboard and primary selection with concatenation enabled. Note that enabling the read functionality is a security risk as it means that any program, even one running on a remote server via SSH can read your clipboard.

`term`

    term xterm-kitty

The value of the TERM environment variable to set. Changing this can break many terminal programs, only change it if you know what you are doing, not because you read some advice on Stack Overflow to change it. The TERM variable is used by various programs to get information about the capabilities and behavior of the terminal. If you change it, depending on what programs you run, and how different the terminal you are changing it to is, various things from key-presses, to colors, to various advanced features may not work.

## OS specific tweaks

`macos_titlebar_color`

    macos_titlebar_color system

Change the color of the kitty window’s titlebar on macOS. A value of `system` means to use the default system color, a value of `background` means to use the background color of the currently active window and finally you can use an arbitrary color, such as `#12af59` or `red`. WARNING: This option works by using a hack, as there is no proper Cocoa API for it. It sets the background color of the entire window and makes the titlebar transparent. As such it is incompatible with `background_opacity`. If you want to use both, you are probably better off just hiding the titlebar with `hide_window_decorations`.

`macos_option_as_alt`

    macos_option_as_alt no

Use the option key as an alt key. With this set to `no`, kitty will use the macOS native ``Option`+`Key`` = unicode character behavior. This will break any ``Alt`+`key`` keyboard shortcuts in your terminal programs, but you can use the macOS unicode input technique. You can use the values: `left`, `right`, or `both` to use only the left, right or both Option keys as Alt, instead.

`macos_hide_from_tasks`

    macos_hide_from_tasks no

Hide the kitty window from running tasks (``Option`+`Tab``) on macOS.

`macos_quit_when_last_window_closed`

    macos_quit_when_last_window_closed no

Have kitty quit when all the top-level windows are closed. By default, kitty will stay running, even with no open windows, as is the expected behavior on macOS.

`macos_window_resizable`

    macos_window_resizable yes

Disable this if you want kitty top-level (OS) windows to not be resizable on macOS.

`macos_thicken_font`

    macos_thicken_font 0

Draw an extra border around the font with the given width, to increase legibility at small font sizes. For example, a value of 0.75 will result in rendering that looks similar to sub-pixel antialiasing at common font sizes.

`macos_traditional_fullscreen`

    macos_traditional_fullscreen no

Use the traditional full-screen transition, that is faster, but less pretty.

`macos_show_window_title_in`

    macos_show_window_title_in all

Show or hide the window title in the macOS window or menu-bar. A value of `window` will show the title of the currently active window at the top of the macOS window. A value of `menubar` will show the title of the currently active window in the macOS menu-bar, making use of otherwise wasted space. `all` will show the title everywhere and `none` hides the title in the window and the menu-bar.

`macos_custom_beam_cursor`

    macos_custom_beam_cursor no

Enable/disable custom mouse cursor for macOS that is easier to see on both light and dark backgrounds. WARNING: this might make your mouse cursor invisible on dual GPU machines.

`linux_display_server`

    linux_display_server auto

Choose between Wayland and X11 backends. By default, an appropriate backend based on the system state is chosen automatically. Set it to `x11` or `wayland` to force the choice.

## Keyboard shortcuts

For a list of key names, see: the GLFW key macros. The name to use is the part after the `GLFW_KEY_` prefix. For a list of modifier names, see: GLFW mods

On Linux you can also use XKB key names to bind keys that are not supported by GLFW. See XKB keys for a list of key names. The name to use is the part after the `XKB_KEY_` prefix. Note that you can only use an XKB key name for keys that are not known as GLFW keys.

Finally, you can use raw system key codes to map keys, again only for keys that are not known as GLFW keys. To see the system key code for a key, start kitty with the `kitty --debug-keyboard` option. Then kitty will output some debug text for every key event. In that text look for `native_code` the value of that becomes the key name in the shortcut. For example:

    on_key_input: glfw key: 65 native_code: 0x61 action: PRESS mods: 0x0 text: 'a'

Here, the key name for the `A` key is `0x61` and you can use it with:

    map ctrl+0x61 something

to map ``ctrl`+`a`` to something.

You can use the special action `no_op` to unmap a keyboard shortcut that is assigned in the default configuration:

    map kitty_mod+space no_op

You can combine multiple actions to be triggered by a single shortcut, using the syntax below:

    map key combine <separator> action1 <separator> action2 <separator> action3 ...

For example:

    map kitty_mod+e combine : new_window : next_layout

this will create a new window and switch to the next available layout

You can use multi-key shortcuts using the syntax shown below:

    map key1>key2>key3 action

For example:

    map ctrl+f>2 set_font_size 20

`kitty_mod`

    kitty_mod ctrl+shift

The value of `kitty_mod` is used as the modifier for all default shortcuts, you can change it in your kitty.conf to change the modifiers for all the default shortcuts.

`clear_all_shortcuts`

    clear_all_shortcuts no

You can have kitty remove all shortcut definition seen up to this point. Useful, for instance, to remove the default shortcuts.

`kitten_alias`

    kitten_alias hints hints --hints-offset=0

You can create aliases for kitten names, this allows overriding the defaults for kitten options and can also be used to shorten repeated mappings of the same kitten with a specific group of options. For example, the above alias changes the default value of `kitty +kitten hints --hints-offset` to zero for all mappings, including the builtin ones.

### Clipboard

`Copy to clipboard`

    map ctrl+shift+c copy_to_clipboard

There is also a `copy_or_interrupt` action that can be optionally mapped to ``Ctrl`+`c``. It will copy only if there is a selection and send an interrupt otherwise. Similarly, `copy_and_clear_or_interrupt` will copy and clear the selection or send an interrupt if there is no selection.

`Paste from clipboard`

    map ctrl+shift+v paste_from_clipboard

`Paste from selection`

    map ctrl+shift+s paste_from_selection
    map shift+insert paste_from_selection

`Pass selection to program`

    map ctrl+shift+o pass_selection_to_program

You can also pass the contents of the current selection to any program using `pass_selection_to_program`. By default, the system’s open program is used, but you can specify your own, the selection will be passed as a command line argument to the program, for example:

    map kitty_mod+o pass_selection_to_program firefox

You can pass the current selection to a terminal program running in a new kitty window, by using the @selection placeholder:

    map kitty_mod+y new_window less @selection

### Scrolling

`Scroll line up`

    map ctrl+shift+up scroll_line_up
    map ctrl+shift+k scroll_line_up

`Scroll line down`

    map ctrl+shift+down scroll_line_down
    map ctrl+shift+j scroll_line_down

`Scroll page up`

    map ctrl+shift+page_up scroll_page_up

`Scroll page down`

    map ctrl+shift+page_down scroll_page_down

`Scroll to top`

    map ctrl+shift+home scroll_home

`Scroll to bottom`

    map ctrl+shift+end scroll_end

`Browse scrollback buffer in less`

    map ctrl+shift+h show_scrollback

You can pipe the contents of the current screen + history buffer as `STDIN` to an arbitrary program using the `launch` function. For example, the following opens the scrollback buffer in less in an overlay window:

    map f1 launch --stdin-source=@screen_scrollback --stdin-add-formatting --type=overlay less +G -R

For more details on piping screen and buffer contents to external programs, see Launching programs in new windows/tabs.

### Window management

``

    map ctrl+shift+enter new_window

You can open a new window running an arbitrary program, for example:

    map kitty_mod+y      launch mutt

You can open a new window with the current working directory set to the working directory of the current window using:

    map ctrl+alt+enter    launch --cwd=current

You can open a new window that is allowed to control kitty via the kitty remote control facility by prefixing the command line with @. Any programs running in that window will be allowed to control kitty. For example:

    map ctrl+enter launch --allow-remote-control some_program

You can open a new window next to the currently active window or as the first window, with:

    map ctrl+n launch --location=neighbor some_program
    map ctrl+f launch --location=first some_program

For more details, see Launching programs in new windows/tabs.

`New OS window`

    map ctrl+shift+n new_os_window

Works like new_window above, except that it opens a top level OS kitty window. In particular you can use new_os_window_with_cwd to open a window with the current working directory.

`Close window`

    map ctrl+shift+w close_window

`Next window`

    map ctrl+shift+] next_window

`Previous window`

    map ctrl+shift+[ previous_window

`Move window forward`

    map ctrl+shift+f move_window_forward

`Move window backward`

    map ctrl+shift+b move_window_backward

`Move window to top`

    map ctrl+shift+` move_window_to_top

`Start resizing window`

    map ctrl+shift+r start_resizing_window

`First window`

    map ctrl+shift+1 first_window

`Second window`

    map ctrl+shift+2 second_window

`Third window`

    map ctrl+shift+3 third_window

`Fourth window`

    map ctrl+shift+4 fourth_window

`Fifth window`

    map ctrl+shift+5 fifth_window

`Sixth window`

    map ctrl+shift+6 sixth_window

`Seventh window`

    map ctrl+shift+7 seventh_window

`Eight window`

    map ctrl+shift+8 eighth_window

`Ninth window`

    map ctrl+shift+9 ninth_window

`Tenth window`

    map ctrl+shift+0 tenth_window

### Tab management

`Next tab`

    map ctrl+shift+right next_tab

`Previous tab`

    map ctrl+shift+left previous_tab

`New tab`

    map ctrl+shift+t new_tab

`Close tab`

    map ctrl+shift+q close_tab

`Move tab forward`

    map ctrl+shift+. move_tab_forward

`Move tab backward`

    map ctrl+shift+, move_tab_backward

`Set tab title`

    map ctrl+shift+alt+t set_tab_title

You can also create shortcuts to go to specific tabs, with 1 being the first tab, 2 the second tab and -1 being the previously active tab, and any number larger than the last tab being the last tab:

    map ctrl+alt+1 goto_tab 1
    map ctrl+alt+2 goto_tab 2

Just as with `new_window` above, you can also pass the name of arbitrary commands to run when using new_tab and use `new_tab_with_cwd`. Finally, if you want the new tab to open next to the current tab rather than at the end of the tabs list, use:

    map ctrl+t new_tab !neighbor [optional cmd to run]

### Layout management

`Next layout`

    map ctrl+shift+l next_layout

You can also create shortcuts to switch to specific layouts:

    map ctrl+alt+t goto_layout tall
    map ctrl+alt+s goto_layout stack

Similarly, to switch back to the previous layout:

    map ctrl+alt+p last_used_layout

### Font sizes

You can change the font size for all top-level kitty OS windows at a time or only the current one.

`Increase font size`

    map ctrl+shift+equal change_font_size all +2.0

`Decrease font size`

    map ctrl+shift+minus change_font_size all -2.0

`Reset font size`

    map ctrl+shift+backspace change_font_size all 0

To setup shortcuts for specific font sizes:

    map kitty_mod+f6 change_font_size all 10.0

To setup shortcuts to change only the current OS window’s font size:

    map kitty_mod+f6 change_font_size current 10.0

### Select and act on visible text

Use the hints kitten to select text and either pass it to an external program or insert it into the terminal or copy it to the clipboard.

`Open URL`

    map ctrl+shift+e kitten hints

Open a currently visible URL using the keyboard. The program used to open the URL is specified in `open_url_with`.

`Insert selected path`

    map ctrl+shift+p>f kitten hints --type path --program -

Select a path/filename and insert it into the terminal. Useful, for instance to run git commands on a filename output from a previous git command.

`Open selected path`

    map ctrl+shift+p>shift+f kitten hints --type path

Select a path/filename and open it with the default open program.

`Insert selected line`

    map ctrl+shift+p>l kitten hints --type line --program -

Select a line of text and insert it into the terminal. Use for the output of things like: ls -1

`Insert selected word`

    map ctrl+shift+p>w kitten hints --type word --program -

Select words and insert into terminal.

`Insert selected hash`

    map ctrl+shift+p>h kitten hints --type hash --program -

Select something that looks like a hash and insert it into the terminal. Useful with git, which uses sha1 hashes to identify commits

`Open the selected file at the selected line`

    map ctrl+shift+p>n kitten hints --type linenum

Select something that looks like `filename:linenum` and open it in vim at the specified line number.

The hints kitten has many more modes of operation that you can map to different shortcuts. For a full description see Hints.

### Miscellaneous

`Toggle fullscreen`

    map ctrl+shift+f11 toggle_fullscreen

`Toggle maximized`

    map ctrl+shift+f10 toggle_maximized

`Unicode input`

    map ctrl+shift+u kitten unicode_input

`Edit config file`

    map ctrl+shift+f2 edit_config_file

`Open the kitty command shell`

    map ctrl+shift+escape kitty_shell window

Open the kitty shell in a new window/tab/overlay/os_window to control kitty using commands.

`Increase background opacity`

    map ctrl+shift+a>m set_background_opacity +0.1

`Decrease background opacity`

    map ctrl+shift+a>l set_background_opacity -0.1

`Make background fully opaque`

    map ctrl+shift+a>1 set_background_opacity 1

`Reset background opacity`

    map ctrl+shift+a>d set_background_opacity default

`Reset the terminal`

    map ctrl+shift+delete clear_terminal reset active

You can create shortcuts to clear/reset the terminal. For example:

    # Reset the terminal
    map kitty_mod+f9 clear_terminal reset active
    # Clear the terminal screen by erasing all contents
    map kitty_mod+f10 clear_terminal clear active
    # Clear the terminal scrollback by erasing it
    map kitty_mod+f11 clear_terminal scrollback active
    # Scroll the contents of the screen into the scrollback
    map kitty_mod+f12 clear_terminal scroll active

If you want to operate on all windows instead of just the current one, use all instead of active.

It is also possible to remap Ctrl+L to both scroll the current screen contents into the scrollback buffer and clear the screen, instead of just clearing the screen:

    map ctrl+l combine : clear_terminal scroll active : send_text normal,application \x0c

`Send arbitrary text on key presses`

You can tell kitty to send arbitrary (UTF-8) encoded text to the client program when pressing specified shortcut keys. For example:

    map ctrl+alt+a send_text all Special text

This will send “Special text” when you press the ``ctrl`+`alt`+`a`` key combination. The text to be sent is a python string literal so you can use escapes like `\x1b` to send control codes or `\u21fb` to send unicode characters (or you can just input the unicode characters directly as UTF-8 text). The first argument to `send_text` is the keyboard modes in which to activate the shortcut. The possible values are `normal` or `application` or `kitty` or a comma separated combination of them. The special keyword `all` means all modes. The modes `normal` and `application` refer to the DECCKM cursor key mode for terminals, and `kitty` refers to the special kitty extended keyboard protocol.

Another example, that outputs a word and then moves the cursor to the start of the line (same as pressing the Home key):

    map ctrl+alt+a send_text normal Word\x1b[H
    map ctrl+alt+a send_text application Word\x1bOH

## Sample kitty.conf

You can download a sample `kitty.conf` file with all default settings and comments describing each setting by clicking: `sample kitty.conf`.