I have made a script that plays audio using ffplay directly onto the terminal. Now after it's executed I am unable to stop the sound without specifically killing it through the terminal or System Monitor.
What I am trying to do is to specify an argument, say audio.sh stop to kill the PID and stop the audio.
But I am unable to do so by simply

PID=$$

elif [[ $# == 1 ]] && [[ $1 == 'stop' ]]; then

         kill ${PID}

I got the problem here, that after running this with the stop argument it will create another instance of the script and then kill it instantly.
So, is there some way to do that?
Here is my full code.

  1 folder=<folder path>

  2 

  3 PID=$$

  4 

  5 if [[ $# == 0 ]]; then 

  6         RANDOM=$$

  7         for i in `seq 1`

  8         do

  9                 R=$(($(($RANDOM%53))+1))

 10                 file=${folder}${R}.mp3

 11                 ffplay -nodisp -autoexit ${file} >/dev/null 2>&1 &

 12         done

 13 elif [[ $# == 1 ]]; then

 14         file=${folder}${1}.mp3

 15         ffplay -nodisp -autoexit ${file} >/dev/null 2>&1 &

 16 elif [[ $# == 1 ]] && [[ $1 == 'stop' ]]; then

 17         kill ${PID}

 18 fi