Monitor audio-cable In or Out

monitor_audio-cable_change.sh

#!/usr/bin/env bash

# NOTE! This script checks card 1, yours may be different
declare -i CARD=1

if amixer -c "$CARD" contents | grep -A2 'Headphone' | grep -q 'values=on'
then
	mkdir /tmp/.audio-cable-connected &>/dev/null
fi

get_unplugged_cable_count(){
	grep -cP '^\s*Pin-ctls:.+OUT' "/proc/asound/card${CARD}/codec#0"
	# > 2 # connected
	# > 4 # unplugged
	return $?
}

declare -a log_cmd=(echo)
declare -i OUT_NUM=-1 TMP_NUM=0
OUT_NUM=$(get_unplugged_cable_count)

while read -r; do
	if grep -qP "^Event '(change|new)' " <<< "$REPLY"; then
		TMP_NUM=$(get_unplugged_cable_count)
		if [[ "$OUT_NUM" -lt "$TMP_NUM" ]] ; then   # cable disconnected
			# vol force-unmute
			# vol set 0
			"${log_cmd[@]}" "Cable(s) unplugged (change: ${OUT_NUM} -> ${TMP_NUM})" 1>&2
			OUT_NUM=$((TMP_NUM+0))
			rmdir /tmp/.audio-cable-connected &>/dev/null
		elif [[ "$OUT_NUM" -gt "$TMP_NUM" ]] ; then # new cable connected
			# vol force-unmute
			# vol set 24%
			"${log_cmd[@]}" "Cable(s) connected (change: ${OUT_NUM} -> ${TMP_NUM})" 1>&2
			OUT_NUM=$((TMP_NUM+0))
			mkdir /tmp/.audio-cable-connected &>/dev/null
		fi
	fi
done < <(echo && stdbuf -oL pactl subscribe)