Shell script to periodically reconnect wifi if raspberry pi disconnects.

crontab_entry.txt

# ping router every 5 minutes, reconnect if fails
*/5 * * * * /usr/bin/sudo /home/pi/Documents/reconnect_wlan0.sh > /dev/null 

reconnect_wlan0.sh

#!/bin/bash

gateway='192.168.0.1'

# ping router to check connection
ping -c4 ${gateway} > /dev/null

# '$?' is the exit code of previous ping command.
# if exit code != 0 (failure)
if [ $? != 0 ]
then
  echo "$(date): No network connection, restarting wlan0" >> /var/log/checkwifi.log

  # turn off wifi
  /sbin/ip link set wlan0 down
  sleep 5
  # restart wifi
  /sbin/ip link set wlan0 up
fi