checker.sh

#!/bin/bash
# Website status checker. by ET (etcs.me)

WORKSPACE=/scripts/isOnline
# list of websites. each website in new line. leave an empty line in the end.
LISTFILE=$WORKSPACE/websites.lst
# Send mail in case of failure to. leave an empty line in the end.
EMAILLISTFILE=$WORKSPACE/emails.lst
# Temporary dir
TEMPDIR=$WORKSPACE/cache

# `Quiet` is true when in crontab; show output when it's run manually from shell.
# Set THIS_IS_CRON=1 in the beginning of your crontab -e.
# else you will get the output to your email every time
if [ -n "$THIS_IS_CRON" ]; then QUIET=true; else QUIET=false; fi

function test {
  response=$(curl -L --write-out %{http_code} --silent --output /dev/null $1)
  filename=$( echo $1 | cut -f1 -d"/" )
  if [ "$QUIET" = false ] ; then echo -n "$p "; fi

  if [ $response -eq 200 ] ; then
    # website working
    if [ "$QUIET" = false ] ; then
      echo -n "$response "; echo -e "\e[32m[ok]\e[0m"
    fi
    # remove .temp file if exist 
    if [ -f $TEMPDIR/$filename ]; then rm -f $TEMPDIR/$filename; fi
  else
    # website down
    if [ "$QUIET" = false ] ; then echo -n "$response "; echo -e "\e[31m[DOWN]\e[0m"; fi
    if [ ! -f $TEMPDIR/$filename ]; then
        while read e; do
            # using mailx command
            echo "$p WEBSITE DOWN" | mailx -s "$1 WEBSITE DOWN ( $response )" $e
            # using mail command
            #mail -s "$p WEBSITE DOWN" "$EMAIL"
        done < $EMAILLISTFILE
        echo > $TEMPDIR/$filename
    fi
  fi
}

# main loop
while read p; do
  test $p
done < $LISTFILE