Simple Bluetooth auto-connect script for systemd

rc-local.service

[Unit]
Description=/etc/rc.local Compatibility
Documentation=man:systemd-rc-local-generator(8)
ConditionFileIsExecutable=/etc/rc.local
After=network.target

[Service]
Type=simple
ExecStart=/etc/rc.local start
ExecStop=/etc/rc.local stop
TimeoutSec=0
RemainAfterExit=yes
GuessMainPID=no
Restart=on-failure
RestartSec=5s

rc.local

#!/bin/sh

ARG="$1"
DEVICE_MAC="A0:B1:C2:D3:E4:F5"

start() {
    bluetoothctl connect "$DEVICE_MAC"

    while bluetoothctl info "$DEVICE_MAC" | grep -c 'Connected: yes' > /dev/null; do
        echo "Device $DEVICE_MAC connected"
        sleep 5
    done

    echo "Device $DEVICE_MAC disconnected"
    exit 1
}

stop() {
    bluetoothctl disconnect "$DEVICE_MAC"
}

case "$ARG" in
    start ) start;;
    stop  ) stop;;
esac