file watcher job

Shell Programming and Scripting
1

Hello,
I am trying to create a file watcher script to check for a file until certain time and throw a message. can some one please help me if there is script handy ??

Thanks,
Sateesh

2 
certain_time=200708031200
while [ $(date +%Y%m%d%H%M) -lt $certain_time ]
do
   watch_file ## replace with whatever watching you want to do
done
printf "%s\n" "Throwing a message"