Reconnect Raspberry Pi wifi when no connection appears

wifi_reconnect.sh

#! /bin/bash
# This code verify that the computer has an ip. When this is not true
# Cron command
# */5 * * * * /my/path/wifi_reconnect

# ip addr show wlan0 |awk -F ":"  '/inet addr/{split($2,a," ");print a[1]}'
IP=$(ifconfig wlan0 | awk '$1 == "inet" {print $2}')

if [ -z $IP ]; then
   # wait for 10 seconds and ask again for your ip
   sleep 10
   IP=$(ifconfig wlan0 | awk '$1 == "inet" {print $2}')
   if [ -z $IP ]; then
       echo Wifi Restarted at `date` >> /tmp/wifi_stats
       ifconfig wlan0 down && ifconfig wlan0 up
   fi
fi