spinner.sh

spinner() {
      local spin="\\|/-"
      local i=0
      tput civis
      while kill -0 "$1" 2>/dev/null; do
          i=$(( (i+1) %4 ))
          printf "\b%s" "${spin:$i:1}"
          sleep 0.07
      done
      tput cnorm
  }
  
  cmd ...
  spinner $!