SHELL脚本判断某端口是否被占用

#!/bin/bash
#检查8080端口是否被占用，如果占用输出1，如果没有被占用输入0
pIDa=`/usr/sbin/lsof -i :8081|grep -v "PID" | awk '{print $2}'`
echo $pIDa
if [ "$pIDa" != "" ];
then
   echo "1"
else
   echo "0"
fi

check_port() {
        echo "正在检测端口。。。"
        netstat -tlpn | grep "\b$1\b"
}
if check_port 3307
then
        echo "端口存在"
    exit 1
else
        echo "端口死亡"
        DATE_N=`date "+%Y-%m%d %H:%M:%S"`
        echo "时间：${DATE_N}" >> check_port.log #记录死亡日志
fi

#判断非负整数
if [[ $port =~^[0-9]*[1-9][0-9]*$ ]];then
	echo "非负整数"
else
	echo "非法"
fi