Frequently Asked Questions#
Some special symbols are rendered small/truncated in kitty?#
The number of cells a Unicode character takes up are controlled by the Unicode standard. All characters are rendered in a single cell unless the Unicode standard says they should be rendered in two cells. When a symbol does not fit, it will either be rescaled to be smaller or truncated (depending on how much extra space it needs). This is often different from other terminals which just let the character overflow into neighboring cells, which is fine if the neighboring cell is empty, but looks terrible if it is not.
Some programs, like Powerline, vim with fancy gutter symbols/status-bar, etc.
use Unicode characters from the private use area to represent symbols. Often
these symbols are wide and should be rendered in two cells. However, since
private use area symbols all have their width set to one in the Unicode
standard, kitty renders them either smaller or truncated. The exception is if
these characters are followed by a space or en-space (U+2002) in which case
kitty makes use of the extra cell to render them in two cells. This behavior
can be turned off for specific symbols using
Using a color theme with a background color does not work well in vim?#
Sadly, vim has very poor out-of-the-box detection for modern terminal features. Furthermore, it recently broke detection even more. It kind of, but not really, supports terminfo, except it overrides it with its own hard-coded values when it feels like it. Worst of all, it has no ability to detect modern features not present in terminfo, at all, even security sensitive ones like bracketed paste.
Thankfully, probably as a consequence of this lack of detection, vim allows users to
configure these low level details. So, to make vim work well with any modern
terminal, including kitty, add the following to your
" Mouse support set mouse=a set ttymouse=sgr set balloonevalterm " Styled and colored underline support let &t_AU = "\e[58:5:%dm" let &t_8u = "\e[58:2:%lu:%lu:%lum" let &t_Us = "\e[4:2m" let &t_Cs = "\e[4:3m" let &t_ds = "\e[4:4m" let &t_Ds = "\e[4:5m" let &t_Ce = "\e[4:0m" " Strikethrough let &t_Ts = "\e[9m" let &t_Te = "\e[29m" " Truecolor support let &t_8f = "\e[38:2:%lu:%lu:%lum" let &t_8b = "\e[48:2:%lu:%lu:%lum" let &t_RF = "\e]10;?\e\\" let &t_RB = "\e]11;?\e\\" " Bracketed paste let &t_BE = "\e[?2004h" let &t_BD = "\e[?2004l" let &t_PS = "\e[200~" let &t_PE = "\e[201~" " Cursor control let &t_RC = "\e[?12$p" let &t_SH = "\e[%d q" let &t_RS = "\eP$q q\e\\" let &t_SI = "\e[5 q" let &t_SR = "\e[3 q" let &t_EI = "\e[1 q" let &t_VS = "\e[?12l" " Focus tracking let &t_fe = "\e[?1004h" let &t_fd = "\e[?1004l" execute "set <FocusGained>=\<Esc>[I" execute "set <FocusLost>=\<Esc>[O" " Window title let &t_ST = "\e[22;2t" let &t_RT = "\e[23;2t" " vim hardcodes background color erase even if the terminfo file does " not contain bce. This causes incorrect background rendering when " using a color theme with a background color in terminals such as " kitty that do not support background color erase. let &t_ut=''
These settings must be placed before setting the
colorscheme. It is
also important that the value of the vim
term variable is not changed
after these settings.
I get errors about the terminal being unknown or opening the terminal failing or functional keys like arrow keys don’t work?#
These issues all have the same root cause: the kitty terminfo files not being available. The most common way this happens is SSHing into a computer that does not have the kitty terminfo files. The simplest fix for that is running:
kitten ssh myserver
It will automatically copy over the terminfo files and also magically enable shell integration on the remote machine.
This ssh kitten takes all the same command line arguments as ssh, you can alias it to something small in your shell’s rc files to avoid having to type it each time:
alias s="kitten ssh"
If this does not work, see Copying terminfo files manually for alternative ways to get the kitty terminfo files onto a remote computer.
The next most common reason for this is if you are running commands as root
using sudo or su. These programs often filter the
TERMINFO environment variable which is what points to the kitty
First, make sure the
TERM is set to
xterm-kitty in the sudo
environment. By default, it should be automatically copied over.
If you are using a well maintained Linux distribution, it will have a
kitty-terminfo package that you can simply install to make the kitty
terminfo files available system-wide. Then the problem will no longer occur.
Alternately, you can configure sudo to preserve
sudo visudo and adding the following line:
Defaults env_keep += "TERM TERMINFO"
If none of these are suitable for you, you can run sudo as
This will make
in the sudo environment. Create an alias in your shell rc files to make this
alias sudo="sudo TERMINFO=\"$TERMINFO\""
If you have double width characters in your prompt, you may also need to explicitly set a UTF-8 locale, like:
export LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8
I cannot use the key combination X in program Y?#
kitten show_key -m kitty
Press the key combination X. If the kitten reports the key press that means kitty is correctly sending the key press to terminal programs. You need to report the issue to the developer of the terminal program. Most likely they have not added support for Comprehensive keyboard handling in terminals.
If the kitten does not report it, it means that the key is bound to some action
in kitty. You can unbind it in
map X no_op
Here X is the keys you press on the keyboard. So for example ctrl+shift+1.
How do I change the colors in a running kitty instance?#
The easiest way to do it is to use the themes kitten, to choose a new color theme. Simply run:
And choose your theme from the list.
You can also define keyboard shortcuts to set colors, for example:
map f1 set_colors --configured /path/to/some/config/file/colors.conf
Additionally, You can use the OSC terminal escape codes to set colors. Examples of using OSC escape codes to set colors:
Change the default foreground color: printf '\x1b]10;#ff0000\x1b\\' Change the default background color: printf '\x1b]11;blue\x1b\\' Change the cursor color: printf '\x1b]12;blue\x1b\\' Change the selection background color: printf '\x1b]17;blue\x1b\\' Change the selection foreground color: printf '\x1b]19;blue\x1b\\' Change the nth color (0 - 255): printf '\x1b]4;n;green\x1b\\'
You can use various syntaxes/names for color specifications in the above examples. See XParseColor for full details.
? is given rather than a color specification, kitty will respond
with the current value for the specified color.
How do I specify command line options for kitty on macOS?#
Apple does not want you to use command line options with GUI applications. To
workaround that limitation, kitty will read command line options from the file
<kitty config dir>/macos-launch-services-cmdline when it is launched
from the GUI, i.e. by clicking the kitty application icon or using
open -a kitty. Note that this file is only read when running via the GUI.
You can, of course, also run kitty from a terminal with command line options,
And within kitty itself, you can always run kitty using just
kitty as it
cleverly adds itself to the
I catted a binary file and now kitty is hung?#
Never output unknown binary data directly into a terminal.
Terminals have a single channel for both data and control. Certain bytes
are control codes. Some of these control codes are of arbitrary length, so if
the binary data you output into the terminal happens to contain the starting
sequence for one of these control codes, the terminal will hang waiting for the
closing sequence. Press
ctrl+shift+delete to reset the terminal.
If you do want to cat unknown data, use
kitty is not able to use my favorite font?#
kitty achieves its stellar performance by caching alpha masks of each rendered character on the GPU, and rendering them all in parallel. This means it is a strictly character cell based display. As such it can use only monospace fonts, since every cell in the grid has to be the same size. Furthermore, it needs fonts to be freely resizable, so it does not support bitmapped fonts.
If you are trying to use a font patched with Nerd Fonts symbols, don’t do that as patching destroys
fonts. There is no need, simply install the standalone
Symbols Nerd Font Mono
NerdFontsSymbolsOnly.zip from the Nerd Fonts releases page). kitty should pick up
symbols from it automatically, and you can tell it to do so explicitly in
case it doesn’t with the
# Nerd Fonts v2.3.3 symbol_map U+23FB-U+23FE,U+2665,U+26A1,U+2B58,U+E000-U+E00A,U+E0A0-U+E0A3,U+E0B0-U+E0D4,U+E200-U+E2A9,U+E300-U+E3E3,U+E5FA-U+E6AA,U+E700-U+E7C5,U+EA60-U+EBEB,U+F000-U+F2E0,U+F300-U+F32F,U+F400-U+F4A9,U+F500-U+F8FF,U+F0001-U+F1AF0 Symbols Nerd Font Mono
Those Unicode symbols beyond the
E000-F8FF Unicode private use area are
If your font is not listed in
kitty +list-fonts it means that it is not
monospace or is a bitmapped font. On Linux you can list all monospace fonts
fc-list : family spacing outline scalable | grep -e spacing=100 -e spacing=90 | grep -e outline=True | grep -e scalable=True
Note that the spacing property is calculated by fontconfig based on actual glyph
widths in the font. If for some reason fontconfig concludes your favorite
monospace font does not have
spacing=100 you can override it by using the
<?xml version="1.0"?> <!DOCTYPE fontconfig SYSTEM "fonts.dtd"> <fontconfig> <match target="scan"> <test name="family"> <string>Your Font Family Name</string> </test> <edit name="spacing"> <int>100</int> </edit> </match> </fontconfig>
After creating (or modifying) this file, you may need to run the following command to rebuild your fontconfig cache:
Then, the font will be available in
How can I assign a single global shortcut to bring up the kitty terminal?#
Bringing up applications on a single key press is the job of the window manager/desktop environment. For ways to do it with kitty (or indeed any terminal) in different environments, see here.
I do not like the kitty icon!#
There are many alternate icons available, click on an icon to visit its homepage:
On macOS and X11 you can put
kitty.app.icns (macOS only) or
kitty.app.png in the
kitty configuration directory, and this icon will be applied
automatically at startup. On X11, this will set the icon for kitty windows.
Unfortunately, on macOS, Apple’s Dock does not change its cached icon so the custom icon will revert when kitty is quit. Run the following to force the Dock to update its cached icons:
rm /var/folders/*/*/*/com.apple.dock.iconcache; killall Dock
If you prefer not to keep a custom icon in the kitty config folder, on macOS, you can also set it with the following command:
# Set kitty.icns as the icon for currently running kitty kitty +runpy 'from kitty.fast_data_types import cocoa_set_app_icon; import sys; cocoa_set_app_icon(*sys.argv[1:]); print("OK")' kitty.icns # Set the icon for app bundle specified by the path kitty +runpy 'from kitty.fast_data_types import cocoa_set_app_icon; import sys; cocoa_set_app_icon(*sys.argv[1:]); print("OK")' /path/to/icon.png /Applications/kitty.app
You can also change the icon manually by following the steps:
kitty.appin the Applications folder, select it and press ⌘+I
kitty.icnsonto the application icon in the kitty info pane
Delete the icon cache and restart Dock:
rm /var/folders/*/*/*/com.apple.dock.iconcache; killall Dock
How do I map key presses in kitty to different keys in the terminal program?#
This is accomplished by using
map alt+s send_text normal,application \x13
This maps alt+s to ctrl+s. To figure out what bytes to use for
send_text you can use the
show_key kitten. Run:
Then press the key you want to emulate. Note that this kitten will only show
keys that actually reach the terminal program, in particular, keys mapped to
actions in kitty will not be shown. To check those first map them to
no_op. You can also start a kitty instance without any shortcuts to
kitty -o clear_all_shortcuts=yes kitten show_key
How do I open a new window or tab with the same working directory as the current window?#
kitty.conf add the following:
map f1 launch --cwd=current map f2 launch --cwd=current --type=tab
Things behave differently when running kitty from system launcher vs. from another terminal?#
This will be because of environment variables. When you run kitty from the system launcher, it gets a default set of system environment variables. When you run kitty from another terminal, you are actually running it from a shell, and the shell’s rc files will have setup a whole different set of environment variables which kitty will now inherit.
You need to make sure that the environment variables you define in your shell’s
rc files are either also defined system wide or via the
env directive in
kitty.conf. Common environment variables that cause issues are those
related to localization, such as
LC_* and loading of
configuration files such as
To see the environment variables that kitty sees, you can add the following
map f1 show_kitty_env_vars
then pressing F1 will show you the environment variables kitty sees.
This problem is most common on macOS, as Apple makes it exceedingly difficult to setup environment variables system-wide, so people end up putting them in all sorts of places where they may or may not work.
I am using tmux and have a problem#
First, terminal multiplexers are a bad idea, do not use them, if at all possible. kitty contains features that do all of what tmux does, but better, with the exception of remote persistence (#391). If you still want to use tmux, read on.
Image display will not work, see tmux issue.
Using ancient versions of tmux such as 1.8 will cause gibberish on screen when pressing keys (#3541).
If you are using tmux with multiple terminals or you start it under one terminal
and then switch to another and these terminals have different
variables, tmux will break. You will need to restart it as tmux does not support
multiple terminfo definitions.
If you use any of the advanced features that kitty has innovated, such as styled underlines, desktop notifications, extended keyboard support, etc. they may or may not work, depending on the whims of tmux’s maintainer, your version of tmux, etc.
I opened and closed a lot of windows/tabs and top shows kitty’s memory usage is very high?#
top is not a good way to measure process memory usage. That is because on modern systems, when allocating memory to a process, the C library functions will typically allocate memory in large blocks, and give the process chunks of these blocks. When the process frees a chunk, the C library will not necessarily release the underlying block back to the OS. So even though the application has released the memory, top will still claim the process is using it.
To check for memory leaks, instead use a tool like Valgrind. Run:
PYTHONMALLOC=malloc valgrind --tool=massif kitty
Now open lots of tabs/windows, generate lots of output using tools like find/yes etc. Then close all but one window. Do some random work for a few seconds in that window, maybe run yes or find again. Then quit kitty and run:
You will see the allocations graph goes up when you opened the windows, then goes back down when you closed them, indicating there were no memory leaks.
For those interested, you can get a similar profile out of valgrind
as you get with top by adding
--pages-as-heap=yes then you will
see that memory allocated in malloc is not freed in free. This can be further
refined if you use
glibc as your C library by setting the environment
MALLOC_MMAP_THRESHOLD_=64. This will cause free to actually free
memory allocated in sizes of more than 64 bytes. With this set, memory usage
will climb high, then fall when closing windows, but not fall all the way back.
The remaining used memory can be investigated using valgrind again, and it will
come from arenas in the GPU drivers and the per thread arenas glibc’s malloc
maintains. These too allocate memory in large blocks and don’t release it back
to the OS immediately.
Why does kitty sometimes start slowly on my Linux system?#
kitty takes no longer (within 100ms) to start than other similar GPU terminal emulators, (and may be faster than some). If kitty occasionally takes a long time to start, it could be a power management issue with the graphics card. On a multi-GPU system (which many modern laptops are, having a power efficient GPU that’s built into the processor and a power hungry dedicated one that’s usually off), even if the answer of the GPU will only be “don’t use me”.
For example, if you have a system with an AMD CPU and an NVIDIA GPU, and you know that you want to use the lower powered card to save battery life and because kitty does not require a powerful GPU to function, you can choose not to wake up the dedicated card, which has been reported on at least one system (#4292) to take ≈2 seconds, by running kitty as:
MESA_LOADER_DRIVER_OVERRIDE=radeonsi __EGL_VENDOR_LIBRARY_FILENAMES=/usr/share/glvnd/egl_vendor.d/50_mesa.json kitty
The correct command will depend on your situation and hardware.
__EGL_VENDOR_LIBRARY_FILENAMES instructs the GL dispatch library to use
libEGL_mesa.so and ignore
libEGL_nvidia.so also available on the
system, which will wake the NVIDIA card during device enumeration.
MESA_LOADER_DRIVER_OVERRIDE also assures that Mesa won’t offer any NVIDIA
card during enumeration, and will instead just use