如果参数为status，那么：
如果/var/lock/subsys/script文件存在，则显示为“script is running.”
否则，则显示为“script is stopped.”
其它任何参数：则显示“script.sh {start|stop|restart|status}”
#!/bin/bash
if [ $1 == start ] ;then
touch /var/lock/subsys/script
echo "Starting script successfully."
elif [ $1 == stop ] ; then
rm -f /var/louk/subsys/script
echo "Stop script finished."
elif [ $1 == restart ];then
rm -f /var/louk/subsys/script
touch /var/lock/subsys/script
echo "Restarting script successfully."
elif [ $1 == status ];then
[ -e /var/lock/subsys/script ]&& echo "script is running." || echo "script is stopped."
else
echo "script.sh {start|stop|restart|status}"
fi
