A small, fast terminal emulator with a Linux Wayland/Vulkan frontend.

Shitty is a hard fork and complete rewrite of Zutty. The original Zutty terminal emulator was created by Tom Szilagyi. Shitty keeps that lineage, but replaces the architecture, renderer, platform integration, testing strategy, and project identity.

Shitty is built for low latency, fast startup, and predictable resource use. It keeps terminal state on the CPU and renders changed cells directly with a Vulkan compute shader.

• VT52 through VT5xx controls and widely used xterm extensions.
• Primary and alternate screens, primary-screen scrollback, margins, tabs, rectangular operations, protected cells, and synchronized output.
• Reflow of primary-screen scrollback when the terminal width changes.
• Unicode grapheme clusters, combining characters, emoji sequences, and double-width characters.
• DEC single-width, double-width, and double-height lines.
• 16-colour, 256-colour, and 24-bit colour, including underline colour and extended underline styles.
• Legacy, modifyOtherKeys, and Kitty keyboard protocols.
• X10, VT200, UTF-8, SGR, SGR-pixel, and urxvt mouse protocols.
• Linear and rectangular selection, primary selection, clipboard integration, OSC 52 policy, and OSC 8 hyperlinks.
• Shell integration, notifications, progress reports, and in-band resize reporting.
• Lazy glyph rasterization, a persistent GPU glyph cache, and damage-driven compute rendering.

Shitty uses UTF-8 internally and exports TERM=xterm-256color to child processes. The host must provide the corresponding terminfo entry.

Shitty is written in C++23 and built with Clang. Building the terminal requires:

• Python 3 and glslangValidator;
• pkg-config;
• Brotli and utf8proc;
• FreeType and HarfBuzz;
• Wayland client headers, xkbcommon, and wayland-scanner;
• Vulkan headers and loader;
• POSIX threads and PTY support;
• libstd, either in third_party/libstd or installed system-wide.

A scalar Base64 implementation is always available. If simdutf 6.5 or newer is installed, the build uses it automatically to accelerate Base64 processing. Fontconfig is also optional. When present, it enables font-family lookup; explicit font file paths are handled directly through FreeType.

A working Vulkan driver and a Wayland compositor are required at runtime. GLFW is built from the pinned third_party/glfw submodule of the project fork; the product build enables only its Linux Wayland and Vulkan paths.

The complete imported conformance suite additionally needs ncurses and Perl.

Initialize the bundled dependencies after cloning:

git submodule update --init --recursive

Build the default install group:

./build

Common build options:

./build -j 8
./build -B .build-debug
CPPFLAGS=-DDEBUG ./build

Start the default shell:

./st

Run a command:

./st -e tmux new-session

Choose the initial terminal size and scrollback capacity:

./st -geometry 120x36 -saveLines 5000

Choose fonts:

./st -font 'DejaVu Sans Mono' -fontsize 16
./st -font 'DejaVu Sans Mono' -dwfont 'Noto Sans Mono CJK JP'

-font and -dwfont accept explicit font file paths. When Fontconfig is available, they also accept family queries and Shitty resolves regular, bold, italic, and bold-italic faces automatically. An optional double-width font is used only when its cell is exactly twice as wide as the primary font at the same height.

Use ./st -v to print the build version without opening a window, ./st -help for the main option list, and ./st -listres for advanced terminal, colour, clipboard, and window-policy options. Boolean flags use -flag to enable and +flag to disable. SHITTY_FONT_SIZE sets the default font size; -fontsize takes precedence.

During a session, Ctrl+Shift++ increases the font size, Ctrl+- decreases it, and Ctrl+0 restores the startup size. Font resizing preserves the terminal's rows and columns by resizing the window to the new cell dimensions.

By default, applications cannot read local selections through OSC 52 and cannot manipulate or query the host window. These operations can be enabled explicitly for trusted applications.

The executable is named st; the desktop application and icon are named shitty:

install -Dm755 ./st /usr/local/bin/st
install -Dm644 shitty.desktop \
  /usr/local/share/applications/shitty.desktop
install -Dm644 shitty.svg \
  /usr/local/share/icons/hicolor/scalable/apps/shitty.svg

Exec=st is resolved through PATH, while Icon=shitty is resolved through the active icon theme.

Run the full native and imported conformance suite:

./build test

Run only the native black-box suite:

./build test_suite

The native suite drives a dedicated headless st_test binary through a real raw PTY and checks externally visible terminal snapshots and output. The production st binary does not expose the test control entry point.

Shitty does not currently implement bidirectional text layout or inline graphics protocols such as sixel. Some historical DEC and xterm extensions are intentionally outside the supported profile.

Shitty is moving from the imported GPL baseline to an MIT-only codebase. It does not intend to retain the GPL as the final project license.

The source snapshot first imported into this repository, and code predating that snapshot, remains licensed under GPLv3-or-later. New Shitty contributions are dual-licensed under GPLv3-or-later and MIT. While GPL-only imported material remains in the tree, distribution of the combined work is still subject to the GPL.

See LICENSE, LICENSE.GPL3, LICENSE.MIT, and CONTRIBUTING.md for the exact terms and contribution policy.

Tom Szilagyi is the original author of Zutty, from which Shitty descends. Shitty retains his copyright notices where historical code lineage requires them; subsequent work is copyright of the Shitty contributors.