A script multiplexer

I had a bunch of dmenu scripts with a keybinding for each one, and I could never remember which key was which.

• A menu is an executable script that prints lines. cmenu runs the scripts, they don't run cmenu.
• One keybinding for all of them. Scripts are picked by prefix, by name, or shown on start.
• Several scripts can share one list, each in its own colour, and one can bring another along.
• Scripts re-run while open - on an interval, after a selection, or with Ctrl+r - so lines stay live.
• The selected line comes back to the script as $1, and the same script can fill a preview pane.
• Nothing is bundled. Write your own, or copy someone else's.

$ go install go.senan.xyz/cmenu@latest

cmenu is a terminal program. Launch it in a terminal with an app ID, and float that window:

# sway
bindsym Mod4+space exec foot --app-id cmenu cmenu
for_window [app_id="cmenu"] floating enable, resize set 1000 600, border none

# hyprland
bind = SUPER, space, exec, foot --app-id cmenu cmenu
windowrule = float, class:cmenu
windowrule = size 1000 600, class:cmenu

Other terminals: kitty --class cmenu, alacritty --class cmenu, wezterm start --class cmenu. On X11, match on the class.

cmenu open <query> starts with a query typed, e.g. cmenu open '#sway' or cmenu open 'c [1+34]'.

$XDG_CONFIG_HOME/cmenu/config.toml is a list of scripts:

[[scripts]]
  triggers = ["on-start", "pre b", "script audio", "interval 750ms"]
  name = "bluetooth"
  path = "menu-bluetooth"

Everything else, like colour or hidden columns, is up to the script with cmenu set.

Input only reaches scripts picked by prefix or name, not on-start or script <name> ones. Each change re-runs the script, so set a debounce.

A script is called in one of three modes:

The smallest script prints lines, and acts on $1:

#!/usr/bin/env bash

if [[ "$#" -gt 0 ]]; then
    mpv "$RADIO_DIR/$1" &
    exit
fi

ls "$RADIO_DIR"

Lines can be split into columns by tabs. cmenu pads them so they line up, except the last, which is free text. Hidden columns stay in $1, so column 1 is the place for an ID:

IFS=$'\t' read -r id _ <<<"$1"

read skips empty columns, so keep the ones you read ahead of any that can be empty. Squash tabs in free text, e.g. gsub(/\t/, " ").

Commands print markers that cmenu reads from the lines and the preview.

cmenu set <key> <value>... configures the script. Print it before the lines, after any run or preview branch.

hide and delimiter apply to the lines after them. The rest apply to the whole list, and the last one wins.

Printed as part of a line:

query and input push the old query, so Escape returns to it. Drilling down keeps the script stateless, since the level it's on is in $CMENU_INPUT:

printf '%s%s\n' "$(cmenu highlight)" "$station"
printf '%s%s\n' "$(cmenu input "[artist:$id]")" "$name" # list an artist's albums
printf '%s%s\n' "$(cmenu input "[rename:$id ")" rename # leave [ open, to type into the input
printf '%s%s\n' "$(cmenu query "#wifi ")" wifi         # jump to another script
printf '%s%s\n' "$(cmenu back)" "new:$CMENU_INPUT"     # add what was typed, and return to the list

Escape, and running a cmenu back line, step out one level:

1. To the query before the last cmenu query or cmenu input.
2. Otherwise, to the script's prefix, clearing anything typed after it.
3. Otherwise, Escape quits, and a cmenu back line just runs.

#!/usr/bin/env bash

pidfile="$XDG_RUNTIME_DIR/menu-radio.pid"

if [[ "$CMENU_MODE" = "preview" ]]; then
    ffprobe -hide_banner "$RADIO_DIR/$1" 2>&1
    exit 0
fi

[[ -f "$pidfile" ]] && IFS=$'\t' read -r current_pid current_station <"$pidfile"

if [[ "$#" -gt 0 ]]; then
    kill "$current_pid" 2>/dev/null
    [[ "$1" = "$current_station" ]] && exit

    mpv --no-video --quiet "$RADIO_DIR/$1" >/dev/null &
    echo -e "$!\t$1" >"$pidfile"
    exit
fi

cmenu set preview true

highlight="$(cmenu highlight)"

find "$RADIO_DIR" -maxdepth 1 -type f -printf "%f\n" | sort | while read -r station; do
    pre=""
    [[ "$station" = "$current_station" ]] && pre="$highlight"
    printf '%s%s\n' "$pre" "$station"
done

#!/usr/bin/env bash

if [[ "$#" -gt 0 ]]; then
    wl-copy "$1"
    exit
fi

cmenu set debounce 300ms

[[ -z "$CMENU_INPUT" ]] && { echo "$(cmenu label)type an expression in [ ]"; exit; }

result="$(awk "BEGIN { print $CMENU_INPUT }" 2>/dev/null)"
[[ -z "$result" ]] && exit

echo "$result"