NetReconnector.sh

#!/bin/bash
# by nickwang wxlcat@gmail.com

NetCard=wlan0                # the netcard connected to the internet
PingTarget=www.baidu.com     # the ping target, router ip or website, etc: 192.168.1.1, www.baidu.com
LogFile=~/NetReconnector.log # log file
LogAll=false                 # log msg no matter whether the net is connected, used to be check whether the script is running.

test -e $LogFile || touch $LogFile

time=$(date "+%Y/%m/%d %H:%M:%S")

ret=$(ping -c 2 -W 1 -I $NetCard $PingTarget | grep 'received' | cut -d ',' -f 2 | cut -d ' ' -f 2)

if [ "$ret" == "0" ]; then
   sudo ifdown $NetCard && sudo ifup $NetCard
   echo "Trying to reconnect: $?, $time" | tee -a $LogFile
else
   if [ "$LogAll" == "true" ]; then
      echo "Network is ok, ret = $ret, $time" | tee -a $LogFile
   fi
fi

exit 0