Linux monitor & react to event in log file

gistfile1.sh

# Linux. Act upon an event in a log file
# www.fduran.com

apt-get upgrade; apt-get install inotify-tools

# create file myalert.sh:
# example finding Exception in tomcat log and sending email

#!/bin/bash
while inotifywait -e modify /path/to/file.log; do
  if tail -n1 /path/to/file.log | grep Exception; then
    # your action here
    echo "Exception in tomcat" |mail -s "Exception alert" email@example.com
  fi
done 

# run with: bash myalert.sh > /dev/null 2>&1 & 
# test with:

echo "Exception" >> /path/to/file.log