# ![Logo: a terminal with a foot shaped prompt](icons/hicolor/48x48/apps/foot.png) foot The fast, lightweight and minimalistic Wayland terminal emulator. ## Index 1. [Features](#features) 1. [Configuration](#configuration) 1. [Troubleshooting](#troubleshooting) 1. [Why the name 'foot'?](#why-the-name-foot) 1. [Fonts](#fonts) 1. [Shortcuts](#shortcuts) 1. [Keyboard](#keyboard) 1. [Normal mode](#normal-mode) 1. [Scrollback search](#scrollback-search) 1. [Mouse](#mouse) 1. [Server (daemon) mode](#server-daemon-mode) 1. [Alt/meta](#alt-meta) 1. [Backspace](#backspace) 1. [DPI and font size](#dpi-and-font-size) 1. [Supported OSCs](#supported-oscs) 1. [Programmatically checking if running in foot](#programmatically-checking-if-running-in-foot) 1. [Requirements](#requirements) 1. [Running](#running) 1. [Building](#building) 1. [Installing](#installing) 1. [Arch Linux](#arch-linux) 1. [Other](#other) 1. [Setup](#setup) 1. [Release build](#release-build) 1. [Profile Guided Optimization](#profile-guided-optimization) 1. [Debug build](#debug-build) 1. [Running the new build](#running-the-new-build) 1. [Credits](#Credits) 1. [Bugs](#bugs) 1. [Mastodon](#mastodon) ## Features * Fast (see [benchmarks](doc/benchmark.md)) * Lightweight, in dependencies, on-disk and in-memory * Wayland native * DE agnostic * User configurable font fallback * On-the-fly font resize * On-the-fly DPI font size adjustment * Scrollback search * Color emoji support * Server/daemon mode (one master process, many windows) * Multi-seat * [Synchronized Updates](https://gitlab.freedesktop.org/terminal-wg/specifications/-/merge_requests/2) support * [Sixel image support](https://en.wikipedia.org/wiki/Sixel) ![wow](doc/sixel-wow.png "Sixel screenshot") ## Configuration **foot** can be configured by creating a file `$XDG_CONFIG_HOME/footrc` (defaulting to `~/.config/footrc`). A template for that can usually be found in `/usr/share/foot/footrc` or [here](https://codeberg.org/dnkl/foot/src/branch/master/footrc). Further information can be found in foot's manpage `foot(5)`. ## Troubleshooting See the [wiki](https://codeberg.org/dnkl/foot/wiki#user-content-troubleshooting) ## Why the name 'foot'? I'm bad at names. Most of my projects usually start out as _foo something_ (for example, [yambar](https://codeberg.org/dnkl/yambar) was _f00bar_ for a while). So why _foot_? _foo terminal_ → _footerm_ → _foot_ Pretty bad, I know. As a side note, if you pronounce the _foo_ part of _foot_ the same way you pronounce _foobar_, then _foot_ sounds a lot like the Swedish word _fot_, which incidentally means (you guessed it) _foot_. ## Fonts **foot** supports all fonts that can be loaded by _freetype_, including **bitmap** fonts and **color emoji** fonts. Foot uses _fontconfig_ to locate and configure the font(s) to use. Since fontconfig's fallback mechanism is imperfect, especially for monospace fonts (it doesn't prefer monospace fonts even though the requested font is one), foot allows you, the user, to configure the fallback fonts to use. This also means you can configure _each_ fallback font individually; you want _that_ fallback font to use _this_ size, and you want that _other_ fallback font to be _italic_? No problem! If a glyph cannot be found in _any_ of the user configured fallback fonts, _then_ fontconfig's list is used. ## Shortcuts These are the default shortcuts. See `man 5 foot` and the example `footrc` to see how these can be changed. ### Keyboard #### Normal mode shift+page up/page down : Scroll up/down in history ctrl+shift+c : Copy selected text to the _clipboard_ ctrl+shift+v : Paste from _clipboard_ ctrl+shift+r : Start a scrollback search ctrl++, ctrl+= : Increase font size by 0,5pt ctrl+- : Decrease font size by 0,5pt ctrl+0 : Reset font size ctrl+shift+n : Spawn a new terminal. If the shell has been configured to emit the OSC 7 escape sequence, the new terminal will start in the current working directory. #### Scrollback search ctrl+r : Search _backward_ for next match ctrl+s : Search _forward_ for next match ctrl+w : Extend current selection (and thus the search criteria) to the end of the word, or the next word if currently at a word separating character. ctrl+shift+w : Same as ctrl+w, except that the only word separating characters are whitespace characters. escape, ctrl+g : Cancel the search return : Finish the search and copy the current match to the primary selection ### Mouse left - **single-click** : Drag to select; when released, the selected text is copied to the _primary_ selection. This feature is **disabled** when client has enabled _mouse tracking_. : Holding shift enables selection in mouse tracking enabled clients. : Holding ctrl will create a block selection. left - **double-click** : Selects the _word_ (separated by spaces, period, comma, parenthesis etc) under the pointer. Hold ctrl to select everything under the pointer up to, and until, the next space characters. left - **triple-click** : Selects the entire row middle : Paste from _primary_ selection right : Extend current selection wheel : Scroll up/down in history ## Server (daemon) mode When run normally, **foot** is a single-window application; if you want another window, start another foot process. However, foot can also be run in a _server_ mode. In this mode, one process hosts multiple windows. Note that this is **nothing** like tabs. When first started in server mode, **no** windows are available. You open new windows by running `footclient`. This is a small process that instructs the foot server to open a new terminal window. The client process remains running until the terminal window is closed. The exit value of the client process is that of the shell that was running in the terminal window. The point of this mode is **a)** reduced memory footprint - all terminal windows will share fonts and glyph cache, and **b)** reduced startup time - loading fonts and populating the glyph cache takes time, but in server mode it only happens once. The downside is a performance penalty; all windows' input and output are multiplexed in the same thread (but each window will have its own set of rendering threads). This means that if one window is very busy with, for example, producing output, then other windows will suffer. And of course, should the server process crash, **all** windows will be gone. Typical usage would be to start the server process (`foot --server`) when starting your Wayland compositor (i.e. logging in to your desktop), and then run `footclient` instead of `foot` whenever you want to launch a new terminal. ## Alt/meta By default, foot prefixes _Meta characters_ with ESC. This corresponds to XTerm's `metaSendsEscape` option set to `true`. This can be disabled programmatically with `\E[?1036l` (and enabled again with `\E[?1036h`). When disabled, foot will instead set the 8:th bit of meta character and then UTF-8 encode it. This corresponds to XTerm's `eightBitMeta` option set to `true`. This can also be disabled programmatically with `rmm` (_reset meta mode_, `\E[?1034l`), and enabled again with `smm` (_set meta mode_, `\E[?1034h`). ## Backspace Foot transmits DEL (`^?`) on backspace. This corresponds to XTerm's `backarrowKey` option set to `false`, and to DECBKM being _reset_. To instead transmit BS (`^H`), press ctrl+backspace. Note that foot does **not** implement DECBKM, and that the behavior described above **cannot** be changed. Finally, pressing alt will prefix the transmitted byte with ESC. ## DPI and font size Font sizes are apparently a complex thing. Many applications use a fixed DPI of 96. They may also multiply it with the monitor's scale factor. This results in fonts with different **physical** sizes (i.e. if measured by a ruler) when rendered on screens with different DPI values. Even if the configured font size is the same. This is not how it is meant to be. Fonts are measured in _point sizes_ **for a reason**; a given point size should have the same height on all mediums, be it printers or monitors, regardless of their DPI. Foot will always use the monitor's physical DPI value. Scale factors are irrelevant (well, they affect e.g. padding, but not the font size). This means the glyphs rendered by foot should always have the same physical height, regardless of monitor. Foot will re-size the fonts on-the-fly when the window is moved between screens with different DPIs values. If the window covers multiple screens, with different DPIs, the highest DPI will be used. _Tip_: QT applications can be configured to work this way too, by exporting the environment variable `QT_WAYLAND_FORCE_DPI=physical`. _Note_: if you configure **pixelsize**, rather than **size**, then DPI changes will **not** change the font size. Pixels are always pixels. ## Supported OSCs OSC, _Operating System Command_, are escape sequences that interacts with the terminal emulator itself. Foot implements the following OSCs: * `OSC 0` - change window icon + title (but only title is actually supported) * `OSC 2` - change window title * `OSC 4` - change color palette * `OSC 7` - report CWD * `OSC 10` - change (default) foreground color * `OSC 11` - change (default) background color * `OSC 12` - change cursor color * `OSC 52` - copy/paste clipboard data * `OSC 104` - reset color palette * `OSC 110` - reset default foreground color * `OSC 111` - reset default background color * `OSC 112` - reset cursor color * `OSC 555` - flash screen (**foot specific**) ## Programmatically checking if running in foot Foot does **not** set any environment variables that can be used to identify foot (reading `TERM` is not reliable since the user may have chosen to use a different terminfo). You can instead use the escape sequences to read the _Secondary_ and _Tertiary Device Attributes_ (secondary/tertiary DA, for short). The tertiary DA response is always `\EP!|464f4f54\E\\`. The `\EP!|` is the standard tertiary DA response prefix, `DCS ! |`. The trailing `\E\\` is of course the standard string terminator, `ST`. In the response above, the interresting part is `464f4f54`; this is the string _FOOT_ in hex. The secondary DA response is `\E[>1;XXYYZZ;0c`, where XXYYZZ is foot's major, minor and patch version numbers, in decimal, using two digits for each number. For example, foot-1.4.2 would respond with `\E[>1;010402;0c`. **Note**: not all terminal emulators implement tertiary DA. Most implement secondary DA, but not all. All _should_ however implement _Primary DA_. Thus, a safe way to query the terminal is to request the tertiary, secondary and primary DA all at once, in that order. All terminals should ignore escape sequences they do not recognize. You will have to parse the response (which in foot will consist of all three DA responses, all at once) to determine which requests the terminal emulator actually responded to. ## Requirements ### Running * fontconfig * freetype * pixman * wayland (_client_ and _cursor_ libraries) * xkbcommon * [tllist](https://codeberg.org/dnkl/tllist) [^1] * [fcft](https://codeberg.org/dnkl/fcft) [^1] [^1]: can also be built as subprojects, in which case they are statically linked. ### Building In addition to the dev variant of the packages above, you need: * meson * ninja * wayland protocols * ncurses * scdoc A note on compilers; in general, foot runs **much** faster when compiled with gcc instead of clang. A profile-guided gcc build can be more than twice as fast as a clang build. **Note** GCC 10.1 has a performance regression that severely affects foot when doing PGO builds and building with `-O2`; it is about 30-40% slower compared to GCC 9.3. The work around is simple: make sure you build with `-O3`. This is the default with `meson --buildtype=release`, but e.g. `makepkg` can override it (`makepkg` uses `-O2` by default). ## Installing foot makes use of a couple of libraries I have developed: [tllist](https://codeberg.org/dnkl/tllist) and [fcft](https://codeberg.org/dnkl/fcft). As such, they will most likely not have been installed already. You can either install them as system libraries, or you can build them as _subprojects_ in foot. When building foot, they will first be searched for as system libraries. If **found**, foot will link dynamically against them. If **not** found, they will be searched for as subprojects. In this case you need to create the `subprojects` directory and clone https://codeberg.org/dnkl/fcft.git and https://codeberg.org/dnkl/tllist.git (see [Other](#other) below). ### Arch Linux Install from AUR: * [foot](https://aur.archlinux.org/packages/foot/) + [foot-terminfo](https://aur.archlinux.org/packages/foot-terminfo/) * [foot-git](https://aur.archlinux.org/packages/foot-git/) + [foot-terminfo-git](https://aur.archlinux.org/packages/foot-terminfo-git/) Or use [makepkg](https://wiki.archlinux.org/index.php/Makepkg) to build the bundled [PKGBUILD](PKGBUILD) (run `makepkg` in the source root directory). Unlike the AUR packages, the bundled PKGBUILD **requires** [tllist](https://codeberg.org/dnkl/tllist) and [fcft](https://codeberg.org/dnkl/fcft) to be installed as system libraries. If you do not want this, please edit the PKGBUILD file, or install manually (see [Other](#other) below). Note that it will do a profiling-guided build, and that this requires a running wayland session since it needs to run an intermediate build of foot. ### Other Foot uses _meson_. If you are unfamiliar with it, the official [tutorial](https://mesonbuild.com/Tutorial.html) might be a good starting point. I also recommend taking a look at the bundled Arch [PKGBUILD](PKGBUILD) file, to see how it builds foot. Especially so if you intend to install a release build of foot, in which case you might be interested in the compiler flags used there. #### Setup If you have not installed [tllist](https://codeberg.org/dnkl/tllist) and [fcft](https://codeberg.org/dnkl/fcft) as system libraries, clone them into the `subprojects` directory: ```sh mkdir -p subprojects pushd subprojects git clone https://codeberg.org/dnkl/tllist.git git clone https://codeberg.org/dnkl/fcft.git popd ``` To build, first, create a build directory, and switch to it: ```sh mkdir -p bld/release && cd bld/release ``` #### Release build ```sh export CFLAGS+="-O3 -march=native -fno-plt" meson --buildtype=release --prefix=/usr -Db_lto=true ``` For performance reasons, I strongly recommend doing a [PGO](#profile-guided-optimization) (Profile Guided Optimization) build. This requires a running Wayland session since we will be executing an intermediate build of foot. If you do not want this, just build: ```sh ninja ``` and then skip to [Running the new build](#running-the-new-build). **For packagers**: normally, you would configure compiler flags using `-Dc_args`. This however "overwrites" `CFLAGS`. `makepkg` from Arch, for example, uses `CFLAGS` to specify the default set of flags. Thus, we do `export CFLAGS+="..."` to at least not throw away those flags. When packaging, you may want to use the default `CFLAGS` only, but note this: foot is a performance critical application that relies on compiler optimizations to perform well. In particular, with GCC 10.1, it is **very** important `-O3` is used (and not e.g. `-O2`) when doing a [PGO](#profile-guided-optimization) build. ##### Profile Guided Optimization First, make sure you have configured a [release](#release-build) build directory, but: If using Clang, make sure to add `-Wno-ignored-optimization-argument -Wno-profile-instr-out-of-date` to `CFLAGS`. If using GCC, make sure to add `-Wno-missing-profile` to `CFLAGS`. Then, tell meson we want to _generate_ profile data, and build: ```sh meson configure -Db_pgo=generate ninja ``` Next, we need to execute the intermediate build of foot, and run a payload inside it that will exercise the performance critical code paths. To do this, we will use the script `scripts/generate-alt-random-writes.py`: ```sh foot_tmp_file=$(mktemp) ./foot --config=/dev/null --term=xterm sh -c " --scroll --scroll-region --colors-regular --colors-bright --colors-rgb ${foot_tmp_file} && cat ${foot_tmp_file}" rm ${foot_tmp_file} ``` You should see a foot window open up, with random colored text. The window should close after ~1-2s. If using Clang, now do (this requires _llvm_ to have been installed): ```sh llvm-profdata merge default_*profraw --output=default.profdata ``` Next, tell meson to _use_ the profile data we just generated, and rebuild: ```sh meson configure -Db_pgo=use ninja ``` Continue reading in [Running the new build](#running-the-new-build) #### Debug build ```sh meson --buildtype=debug ../.. ninja ``` #### Running the new build You can now run it directly from the build directory: ```sh ./foot ``` But note that it will default to `TERM=foot`, and that this terminfo has not been installed yet. However, most things should work with the `xterm-256color` terminfo: ```sh ./foot --term xterm-256color ``` But, I **recommend** you install the `foot` and `foot-direct` terminfo files. You can either copy them manually (typically to `/usr/share/terminfo/f` - but this is dependens on the distro), or just install everything: ```sh ninja install ``` # Credits * [Ordoviz](https://codeberg.org/Ordoviz), for designing and contributing foot's [logo](icons/hicolor/48x48/apps/foot.png). # BUGS Please report bugs to https://codeberg.org/dnkl/foot/issues The report should contain the following: * Which Wayland compositor (and version) you are running * Foot version (`foot --version`) * Log output from foot (start foot from another terminal) * If reporting a crash, please try to provide a `bt full` backtrace **with symbols** (i.e. use a debug build) * Steps to reproduce. The more details the better # Mastodon Every now and then I post foot related updates on [@dnkl@linuxrocks.online](https://linuxrocks.online/@dnkl)