Raspberry PiでWi-Fi接続が切れたときに自動で再接続させるスクリプト for Raspbian

wifirect.sh

#!/bin/bash

USSID="<自環境のSSIDを入力>"
IF_FILE="/etc/network/interfaces"
PARAM_GATEWAY=`grep -i gateway ${IF_FILE} | cut -f2 -d' '`
PARAM_ADDR=`grep -i address ${IF_FILE} | cut -f2 -d' '`


ping -c 4 ${PARAM_GATEWAY} > /dev/null 2>&1
flag=$?

if [ $flag -ne 0 ]; then
  /sbin/ifconfig wlan0 | grep inet | grep ${PARAM_ADDR} > /dev/null 2>&1
  flag=$?

  if [ $flag -ne 0 ]; then
    /sbin/iwconfig wlan0 | grep ${USSID} > /dev/null 2>&1
    flag=$?

    if [ $flag -ne 0 ]; then
      /etc/ifplugd/ifplugd.action wlan0 up
      sleep 30
      /usr/sbin/service ntp restart
    fi
  fi
fi