让scroll lock指示灯闪烁

scroll lock 指示灯闪烁，可以起提醒作用，没人会用tty19吧？
#!/bin/bash
#email:[email protected]
#msn:[email protected]
#oicq:2899589
if [ $# != 1 ];then
echo usage :$0 time
exit 0
fi
n=1
#sleep $1&&let "n=0"&
while [ $n -le $1 ]
do
n=`expr $n + 1`
setleds -L +scroll < /dev/tty19
#setleds -L -caps < /dev/tty19
sleep 0.5
setleds -L -scroll < /dev/tty19
#setleds -L +caps < /dev/tty19
sleep 0.5
done
#setleds -L -caps < /dev/tty19