仅在 IP 更改时通知

Question

我使用此脚本记录分机 IP 更改

host myip.opendns.com resolver1.opendns.com | sed -n -e 's/^\(.*\)\(myip.opendns.com has address \)//p' | sed "s/^/`date` /" » /DataVolume/shares/Public/MyIP.txt

如何仅在 IP 更改时创建警报（可能创建单独的日志文件或发送邮件）？

Answer 1

大致如下：

#!/bin/bash

previp=

while :; do
    ip=$(host myip.opendns.com resolver1.opendns.com |
        sed -n '/.* has address \(.*\)/ { s///; p; q; }' )
    if [[ $previp != "$ip" ]]; then
        msg="$(date): IP change from '$previp' to '$ip'"
        echo "$msg" >> logfile
        mail -s "IP change" somebody@somewhere <<< "$msg"
        previp=$ip
    fi  
    sleep 60
done

如果您希望它只运行一次（例如来自 crontab）：

#!/bin/bash

ipfile='/tmp/previous_ip'

ip=$(host myip.opendns.com resolver1.opendns.com |
    sed -n '/.* has address \(.*\)/ { s///; p; q; }' )

if ! [[ -f $ipfile ]]; then
    echo "$ip" > "$ipfile"
fi

read -r previp < "$ipfile"

if [[ $previp != "$ip" ]]; then
    msg="$(date): IP change from '$previp' to '$ip'"
    echo "$msg" >> logfile
    mail -s "IP change" somebody@somewhere <<< "$msg"
    echo "$ip" > "$ipfile"
fi

仅在 IP 更改时通知

Notify only when IP changes

bash

logging

ip

alert