Shell Programming and Scripting

I have a log file which keeps on updating. What I need to do is write a different script, which could moniter the log file continously, and email some stakeholders if some error has occured..

log file gets a message from various sources, and after getting/processing the message, prints an sucess or a Error whatever the case may be..

its like..

Code:

 
...
New Message
log...
log...
log...
<Messagefrom source1>
log..
log..
Insert Success
...
New Message
log...
log...
log...
<Message from source2>
log..
log..
Insert Error

Now I need to keep listening to this log file, and whenever a "source2" message comes and and "Insert Error" is printed, I need to do a process(send en email to stakeholders)

How can this be achieved in Unix Shell-Script.
Please help.

---------- Post updated at 01:58 AM ---------- Previous update was at 01:53 AM ----------

okay. is it something to do with Log-File rotation?

Assuming your log file is updated every time with 10 new lines, we are extracting the last ten lines and checking for the condition. You can use nawk instead of awk if the machine is Sun Solaris..

Code:

#!/bin/ksh

ERR_STATUS=$(tail -10 /path/to/inputfile.log | awk '$0 ~ /source2|Insert Error/{++i}(i==2){print "error ocured"}')
if [[ -n "$ERR_STATUS" ]]
then
	echo "Check log for Insert error" | mailx -s "Log - Insert Error" yourid@mail.com
fi