•XDG_CONFIG_HOME/footrc

•~/.config/footrc

Comma separated list of fonts to use, in fontconfig format (see FONT FORMAT).

The first font is the primary font. The remaining fonts are fallback fonts that will be used whenever a glyph cannot be found in the primary font.

The fallback fonts are searched in the order they appear. If a glyph cannot be found in any of the fallback fonts, the dynamic fallback list from fontconfig (for the primary font) is searched.

Default: monospace.

Initial window width and height in pixels (subject to output scaling), on the form WIDTHxHEIGHT. Default: 700x500.

Padding between border and glyphs, in pixels (subject to output scaling), on the form XxY. Default: 2x2.

Initial window mode for each newly spawned window: windowed, maximized or fullscreen. Default: windowed.

Executable to launch. Typically a shell. Default: $SHELL if set, otherwise the user's default shell (as specified in /etc/passwd). You can also pass arguments. For example "/bin/bash --norc".

Boolean. If enabled, the shell will be launched as a login shell, by prepending a '-' to argv[0]. Default: no.

Value to set the environment variable TERM to. Default: foot.

Initial window title. Default: foot.

Value to set the app-id property on the Wayland window to. The compositor can use this value to e.g. group multiple windows, or apply window management rules. Default: foot.

Number of scrollback lines. Default: 1000.

Number of threads to use for rendering. Set to 0 to disable multithreading. Default: the number of available logical CPUs (including SMT). Note that this is not always the best value. In some cases, the number of physical cores is better.

Configures the default cursor style, and is one of: block, bar or underline. Note that this can be overridden by applications. Default: block.

Boolean. Enables blinking cursor. Note that this can be overridden by applications. Default: no.

Two RRGGBB values specifying the foreground (text) and background (cursor) colors for the cursor. Default: inversed foreground and background colors. Note that this value only applies to the block cursor. The other cursor styles are always rendered with the foreground color.

Default RRGGBB foreground color. This is the color used when no ANSI color is being used. Default: dcdccc.

Default RRGGBB background color. This is the color used when no ANSI color is being used. Default: 111111.

The eight basic ANSI colors. Default: 222222, cc9393, 7f9f7f, d0bf8f, 6ca0a3, dc8cc3, 93e0e3 and dcdccc (a variant of the zenburn theme).

The eight bright ANSI colors. Default: 666666, dca3a3, bfebbf, f0dfaf, 8cd0d3, fcace3, b3ffff and ffffff (a variant of the zenburn theme).

Background translucency. A value in the range 0.0-1.0, where 0.0 means completely transparent, and 1.0 is opaque. Default: 1.0.

Which type of window decorations to prefer: client (CSD) or server (SSD). Note that this is only a hint to the compositor. Depending on the compositor's configuration and capabilities, it may not have any effect. Default: server.

Height, in pixels (subject to output scaling), of the titlebar. Default: 26.

Titlebar AARRGGBB color. Default: use the default foreground color.

Width, in pixels (subject to output scaling), of the minimize/maximize/close buttons. Default: 26.

Minimize button's AARRGGBB color. Default: use the default regular4 color (blue).

Maximize button's AARRGGBB color. Default: use the default regular2 color (green).

Close button's AARRGGBB color. Default: use the default regular1 color (red).

Scrolls up/back in history. Default: Shift+Page_Up.

Scroll down/forward in history. Default: Shift+Page_Down.

Copies the current selection into the clipboard. Default: Control+Shift+C.

Pastes from the clipboard. Default: Control+Shift+V.

Pastes from the primary selection. Default: not bound (to a key, see mouse-bindings).

Starts a scrollback/history search. Default: Control+Shift+R.

Increases the font size by 0.5pt. Default: Control+plus Control+equal Control+KP_Add.

Decreases the font size by 0.5pt. Default: Control+minus Control+KP_Subtract.

Resets the font size to the default. Default: Control+0 Control+KP_0.

Spawns 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. Default: Control+Shift+N.

Minimizes the window. Default: not bound.

Toggle the maximized state. Default: not bound.

Toggles the fullscreen state. Default: not bound.

Pipes the currently visible text, or the entire scrollback, to an external tool. The syntax for this option is a bit special; the first part of the value is the command to execute enclosed in "[]", followed by the binding(s).

You can configure multiple pipes as long as the command strings are different and the key bindings are unique.

Note that the command is not automatically run inside a shell; use sh -c "command line" if you need that.

Example:

Default: not bound

Pastes from the primary selection. Default: BTN_MIDDLE.

•Dina:weight=bold:slant=italic

•Courier New:size=12

These two values control the timeouts (in nanoseconds) that are used to mitigate screen flicker caused by clients writing large, non-atomic screen updates.

If a client splits up a screen update over multiple write(3) calls, we may end up rendering an intermediate frame, quickly followed by another frame with the final screen content. For example, the client may erase part of the screen (or scroll) in one write, and then write new content in one or more subsequent writes. Rendering the frame when the screen has been erased, but not yet filled with new content will be perceived as screen flicker.

The real solution to this is Application Synchronized Updates (https://gitlab.freedesktop.org/terminal-wg/specifications/-/merge_requests/2).

The problem with this is twofold - first, it has not yet been standardized, and thus there are not many terminal emulators that implement it (foot does implement it), and second, applications must be patched to use it.

Until this has happened, foot offers an interim workaround; an attempt to mitigate the screen flicker without affecting neither performance nor latency.

It is based on the fact that the screen is updated at a fixed interval (typically 60Hz). For us, this means it does not matter if we render a new frame at the beginning of a frame interval, or at the end. Thus, the goal is to introduce a delay between receiving client data and rendering the resulting state, but without causing a frame skip.

While it should be possible to estimate the amount of time left until the next frame, foot's algorithm is currently not that advanced, but is based on statistics I guess you could say - the delay we introduce is so small that the risk of pushing the frame over to the next frame interval is also very small.

Now, that was a lof of text. But what is it foot actually does?

When receiving client data, it schedules a timer, the delayed-render-lower. If we do not receive any more client data before the timer has run out, we render the frame. If however, we do receive more data, the timer is re-scheduled. That is, each time we receive client data, frame rendering is delayed another delayed-render-lower nanoseconds.

Now, while this works very well with most clients, it would be possible to construct a malicious client that keeps writing data at a slow pace. To the user, this would look like foot has frozen as we never get to render a new frame. To prevent this, an upper limit is set - delayed-render-upper. If this timer runs out, we render the frame regardless of what the client is doing.

If changing these values, note that the lower timeout must be set lower than the upper timeout, but that this is not verified by foot. Furthermore, both values must be less than 16ms (that is, 16000000 nanoseconds).

You can disable the feature altoghether by setting either value to 0. In this case, frames are rendered "as soon as possible".

Default: lower=500000 (0.5ms), upper=8333333 (8.3ms - half a frame interval).

This option controls the amount of virtual memory used by the pixmap memory to which the terminal screen content is rendered.

It does not change how much physical memory foot uses.

Foot uses a memory mapping trick to implement fast rendering of interactive scrolling (typically, but applies to "slow" scrolling in general). Example: holding down the 'up' or 'down' arrow key to scroll in a text editor.

For this to work, it needs a large amount of virtual address space. Again, note that this is not physical memory.

On a normal x64 based computer, each process has 128TB of virtual address space, and newer ones have 64PB. This is an insane amount and most applications do not use anywhere near that amount.

Each foot terminal window can allocate up to 2GB of virtual address space. With 128TB of address space, that means a maximum of 65536 windows in server/daemon mode (for 2GB). That should be enough, yes?

However, the Wayland compositor also needs to allocate the same amount of virtual address space. Thus, it has a slightly higher chance of running out of address space since it needs to host all running Wayland clients in the same way, at the same time.

In the off chance that this becomes a problem for you, you can reduce the amount used with this option.

Or, for optimal performance, you can increase it to the maximum allowed value, 2GB (but note that you most likely will not notice any difference compared to the default value).

Note: this feature is always disabled in 32-bit.

Default: 512. Maximum allowed: 2048 (2GB).