等待加载时光标旋转效果

spin()
{
  local i=0
  local sp='/-\|'
  local n=${#sp}
  printf ' '
  sleep 0.1
  while true; do
    printf '\b%s' "${sp:i++%n:1}"
    sleep 0.1
  done
}


spin &
SPIN_PID=$!
....
....
....
kill -9 ${SPIN_PID} >/dev/null 2>&1