#!/bin/bash
##### checktime.sh / rb / 2025
##### check time between a webserver and the localtime

uri="https://borwinius.de"
##### check if curl or wget and get webservertime
if [ -x $(which curl) ]; then
curl -skI $uri -o /dev/null || exit 60
timestring=$(curl --head  $uri 2>>/dev/null | grep -e Date: | cut -d: -f2-4)
else
 wget --no-check-certificate --spider $uri -q -O - 2>&1 || exit 5
 timestring=$(wget -S $uri -q -O - 2>&1 | grep -e Date: | head -1 | cut -d: -f2-4)
fi
#timestring="Mon, 13 Jan 2025 12:22:33 GMT"
echo $timestring
webseconds=$(date -d "$timestring" +%s)
echo $webseconds

##### get localtime
localseconds=$(date +%s)
echo $localseconds
##### check if the difference gt 5 minutes
difference=$(expr $webseconds - $localseconds )
# echo $difference
if [ "${difference##*[+-]}" -ge 300 ]; then
 echo "ERROR: $difference greater then 300 secs"
 exit 1
else
 echo "OK:    $difference smaller then 300 secs "
fi