play_sound.sh

#!/bin/bash

soundbar_on_vol_to_5 () {
  while read -r line
  do
    cec-client -d 1
  done < /home/pi/on_with_vol_to_5.txt
}

if [[ $1 = "start" ]]
then
    soundbar_on_vol_to_5 &
    sleep 15
    killall cec-client
    play /home/pi/output.mp3 > /dev/null 2>&1 &
elif [[ $1 = "stop" ]]
then
    killall play
    echo 'standby 5' | cec-client -s -d 1
elif [[ $1 = "status" ]]
then
    status=$(echo 'pow 5' | cec-client -s -d 1 | grep "power status:")
    if [[ $status == *standby* ]]
    then
        printf "off"
    elif [[ $status == *on* ]]
    then
        printf "on"
    fi
else
    echo "invalid argument"
fi