linux shell腳本 取得外網IP並保存到文件

#!/bin/bash

if [! -f /root/ip.txt];then
echo $(date +%Y"."%m"."%d" "%k":"%M":"%S) > /root/ip.txt
curl http://members.3322.org/dyndns/getip >> /root/ip.txt
fi

while var=$(curl http://members.3322.org/dyndns/getip) || true; do

iptxt=$(tail -1 /root/ip.txt)
#echo $iptxt
#echo $var

if [ $var != $iptxt ];then

echo $(date +%Y"."%m"."%d" "%k":"%M":"%S) >> /root/ip.txt

echo "$var" >> /root/ip.txt

#echo "record ip"

#else

#echo "ip is same"

fi

sleep 60s
done