simple script: check if website is online

onlinecheck

#!/bin/bash

if [ -z "$1" ]; then
    echo "usage: onlinecheck [domain]"
    echo "example: onlinecheck www.heise.de"
    exit
fi

FOLDER="/tmp/onlinecheck/"

MAILTO=root
CHECK=`curl --http1.1 -s -I "$1" | grep HTTP | grep "200 OK"`
MD5SUM=`echo -n "$1" | md5sum - | xargs | cut -f1 -d " "`
FILENAME="${FOLDER}${MD5SUM}"

if [ -z "$CHECK" ]; then
    mkdir -p $FOLDER
    echo "$1 is offline"
    if [ ! -f $FILENAME ]; then
        touch $FILENAME
        echo "send email"
        echo -n "$1 is offline" | mail -s "$1 is offline" $MAILTO
    fi

else
   if [ -f $FILENAME ]; then
       echo -n "$1 is back online" | mail -s "$1 is back online" $MAILTO
       rm -f $FILENAME
   fi
   echo "$1 is online"
fi

if [ -d "$FOLDER" ]; then
    find $FOLDER -type f -mmin +60 -exec rm -f "{}" \;
fi