rpi wifi time update

this is in /etc/rc.local

must install rdate first so this will run and set the time

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
  printf "My IP address is %s\n" "$_IP"

fi

sudo rdate -n -4 time-a.nist.gov &

exit 0

'other time servers can be found at the folling website'

http://tf.nist.gov/tf-cgi/servers.cgi