Shell script to monitor running services such as web/http, ssh, mail

Shell script to monitor running services such as web/http, ssh, mail etc. If service fails script will send an Email to ADMIN user

monitor-linux-service.bash

#!/bin/bash
# Shell script to monitor running services such as web/http, ssh, mail etc.
# If service fails it will send an Email to ADMIN user
# -------------------------------------------------------------------------
# Copyright (c) 2006 nixCraft project <http>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
# See URL for more info
# http://www.cyberciti.biz/tips/processing-the-delimited-files-using-cut-and-awk.html
# ---------------------------------------------------
# service port
ports="22 80 25"

# service names as per above ports
service="SSH WEB MAIL"

# No of services to monitor as per (above ports+1)
SCOUNTER=4

#Email id to send alert
ADMINEMAIL="admin@myispname.com"

# counter
c=1
echo "Running services status:"

# use sudo if you want i.e. sudo /bin/netstat
/bin/netstat -tulpn | grep -vE '^Active|Proto' | while read LINE
do
 sendMail=0
 # get active port name and use : as delimiter
 t=$(echo $LINE | awk '{ print $4}' | cut -d: -f2)
 [ "$t" == "" ] && t=-1 || :
 # get service name from $services and : as delimiter
 sname=$(echo $service | cut -d' ' -f$c)
 sstatus="$sname: No"
 # now compare port
 for i in $ports
 do
  if [ $i -eq $t ]; then
   sstatus="$sname: Ok"
    sendMail=1
  fi
 done
 # display service status as OK or NO
 echo "$sstatus"
 #next service please
 c=$( expr $c + 1 )
 [ "$sendMail" == "0" ] && echo $sstatus | mail -s "service down $sstatus" $ADMINEMAIL || :
 # break afer 3 services
 [ $c -ge $SCOUNTER ] && break || :
done
</http>