Update clock (raspberry pi)

update-clock.sh

#!/bin/bash

SERVICE_TIMEOUT=5 # seconds
NTP_SERVER=time.nist.gov
NTPD_PIDFILE=/var/run/ntpd.pid

log() {
  [ $# -lt 2 ] && echo "Invalid call to log(): too few arguments" 1>&2 && exit 1
  local lev="$1" ; shift
  local fmt="$1\n" ; shift
  printf "$fmt" "$@" | logger -s -t "$(basename $0)" -p user.$lev
}
[ "$USER" != "root" ] && log error "Only root can run this script" && exit 1

#TODO fix?? and use ntpd_is_running()
# ntpd_is_running() {
#   if [[ -f $NTPD_PIDFILE ]]; then
#     ntpd_pid=$( cat /var/run/ntpd.pid )
#     if [[ -z "$( ps --no-headers $ntpd_pid )" ]]; then
#       return 1
#     fi
#   fi
#   return 0
# }

if [[ -f $NTPD_PIDFILE ]]; then
  log info 'Stopping NTPd...'
  service ntp stop
  [ $? -ne 0 ] && log error 'Failed to stop NTPd' && exit 1
  for (( i=1; i < $SERVICE_TIMEOUT; i++ )); do
    sleep 1 ; [ ! -f $NTPD_PIDFILE ] && i=$SERVICE_TIMEOUT
  done
  [ -f $NTPD_PIDFILE ] && log error 'Failed to stop NTPd' && exit 1
fi

log info 'Forcing time update...'
ntpd -4nNgq -u ntp:ntp -c /dev/stdin -l /dev/stdout <<EOCONFIG
server $NTP_SERVER
EOCONFIG
[ $? -ne 0 ] && log error 'Failed to force time update' && exit 2

log info 'Restarting NTPd...'
service ntp start
[ $? -ne 0 ] && log error 'Failed to restart NTPd' && exit 1
for (( i=1; i < $SERVICE_TIMEOUT; i++ )); do
  sleep 1 ; [ -f $NTPD_PIDFILE ] && i=$SERVICE_TIMEOUT
done
[ ! -f $NTPD_PIDFILE ] && log error 'Failed to restart NTPd' && exit 1
ntpd_pid=$( cat /var/run/ntpd.pid )
[ -z "$( ps --no-headers $ntpd_pid )" ] && log error 'Failed to restart NTPd' && exit 1

log info 'Saving fake-hwclock...'
fake-hwclock save force
[ $? -ne 0 ] && log error 'Failed to save fake-hwclock' && exit 1

log notice 'Updated clock via NTP'