This is a script to check if the apache MaxClientsVhost limit has been hit, it's used on PuffinServer and a email is sent to root every day when the MaxClientsVhost limit is reached.

#!/bin/bash

# This script checks for the Apache MaxClientsVhost limit being hit
# It's run via /etc/logrrotate.d/apache2 just before thenlogs are rotated
# If an email address is passed to the script then the results will be sent 
# out by email.

# Location of the apache log file we are checking
LOGFILE=/var/log/apache2/error.log

# Name of the server this is running on
HOSTNAME=$(hostname -f)

# The lines are are grepping for 
GREP=$(grep MaxClientsVhost $LOGFILE | uniq -u)

# The subject line of the email 
SUBJECT="MaxClientsVhost limit hit on $HOSTNAME"

# Optional email address
EMAIL=$1

# check that the script is being run by root
if [[ "$(id -u)" != "0" ]] ; then
  echo "You must run $0 as root or via sudo" 
  exit 2
fi

# Check to see if any errors were found
if [[ $GREP ]]; then
  # Check for a email address 
  if [[ $1 ]]; then
    echo "$GREP" | mutt -s "$SUBJECT" $EMAIL
  # Display the results of the grep
  else [[ ! $1 ]]
    echo "Supply a email address on the command line to send the following results by email" 
    echo ""
    echo "$GREP"
  fi
else
   # We don't want any output if an email address is supplied 
   if [[ ! $EMAIL ]] ; then
     echo "No recent errors were found" 
   fi
fi

The script is called via /etc/logrotate.d/apache2 which contains:

/var/log/apache2/*.log {
        daily
        missingok
        rotate 28
        compress
        delaycompress
        notifempty
        create 640 root adm
        sharedscripts
        prerotate
                /usr/local/webarch/bin/maxclients root@localhost
        endscript
        postrotate
                /etc/init.d/apache2 reload > /dev/null
        endscript
}