this script checks the existence of a char sequence in the last X number of lines of a files and plays a wave file if a match is made.

logchecker.sh

#!/bin/bash
#this script checks the existence of a char sequence in the last X number of lines of a files and plays a wave file if a match is made.
# sh logchecker.sh <number of lines to tail at one go> <logfile> <char sequence> <wav file to play>
while [ 1 -gt 0 ]; do
	tail -n $1 $2 | grep -e "$3"
	if [ $? -lt 1 ]; then 
		aplay $4 ;
		exit ;
	fi
	sleep 10; #check interval 
done