dmenu-runner

#!/bin/sh

# POSIX-compliant (bashism-free) shell script to use a dmenu-like program
# to select/run executables found in $PATH, saving and prioritizing previous
# commands. An alternative to the "dmenu_run" command shipped with dmenu and the
# dmenu_run_history script available from the suckless website:
# https://tools.suckless.org/dmenu/scripts/dmenu_run_with_command_history/

# Based on:
# https://gitlab.com/FlyingWombat/my-scripts/blob/a0cb5717777c1587af381004aa8fb048206bee55/sway-launcher

# configuration

# set your preferred dmenu-like program in the environment variable $DMENU_PROGRAM
# examples: "dmenu", "rofi -dmenu", "term-dmenu", or just "fzf" to run in your current terminal
[ -z "$DMENU_PROGRAM" ] && DMENU_PROGRAM='term-dmenu --no-extended --print-query --no-sort'
if [ -z "$RUNNER_HISTFILE" ]; then
	cachedir=${XDG_CACHE_HOME:-"$HOME/.cache"}
	mkdir -p "$cachedir"
	RUNNER_HISTFILE="$cachedir/dmenu_runner_history"
fi

# Get shell command list

# This may include the occasional non-executable file

# shellcheck disable=SC2046 # word-splitting isn't an issue here.
command_list=$(stest -flx $(echo "$PATH" | tr : '\n' | sort -u) | sort -u)

# read existing command history

if [ -f "$RUNNER_HISTFILE" ]; then
	command_history=$(cat "$RUNNER_HISTFILE")
else
	command_history=""
fi

# search command list

command_str=$(printf "%s\n" "${command_history}" "${command_list}" \
	| sed -E 's/^[0-9]+ (.+)$/\1/' \
	| $DMENU_PROGRAM \
	| tail -n1) || exit 1

if [ "$command_str" = "" ]; then
	exit 1
fi

# using \E flag from perl regex
test "${command_str#*\\E}" != "$command_str" && echo "command can't contain '\E'"
test "${command_str#*\\E}" != "$command_str" && exit 1

update_history() {
	# get full line from history (with count number)
	hist_line=$(echo "$command_history" | grep -Pe "^[0-9]+ \Q$command_str\E$")

	if [ "$hist_line" = "" ]; then
		hist_count=1
	else
		# Increment usage count
		hist_count=$(echo "$hist_line" | sed -E 's/^([0-9]+) .+$/\1/')
		hist_count=$((hist_count + 1))
		# delete line, to add updated later
		command_history=$(echo "$command_history" \
			| grep --invert-match -Pe "^[0-9]+ \Q$command_str\E$")
	fi

	# update history
	update_line="${hist_count} ${command_str}"
	printf "%s\n" "${update_line}" "${command_history}" \
		| sort --numeric-sort --reverse >"$RUNNER_HISTFILE"
}
update_history &

# execute command
# shellcheck disable=SC2154
if [ -n "$SWAYSOCK" ]; then
	swaymsg -t command exec "$command_str" &
else
	eval "$command_str" &
	# "disown" is a bashism; use it if only if the shell supports job control
	if command -v disown >/dev/null; then
		# shellcheck disable=SC2039
		disown
	fi
fi

# vi:ft=sh