Shell Programming and Scripting

I have an interesting dilemma. I am trying make a script that is continuously scanning for new data. This script cannot be paused or stopped it needs to run constantly. I also want to periodically time stamp the output to make it easier to sort through. The trouble is that I can't think of a way to write a single script to do this.

I can however write two separate scripts to perform the function. The catch is that every time the time-stamp script goes to write the time-stamp it erases the contents of said file.

Can anyone think of a way around this because I am out of ideas.

What scripting language are you using or better yet please post your code. Thank you.

Script 1 this is the one that must run constantly. Pretty basic I know.

Code:

#! /bin/sh
actual=`date`
echo "Process ID for tcpdump launched $actual is $$" > /log/procID.log
tcpdump -i en0 -A -s 0 port 80 | grep Referer: > /log/tcpdump.log

Script 2 this is the one that just timestamps the log created by the first script

Code:

#! /bin/sh
count=1
actual=`date`
echo "Process ID for the timer launched $actual is $$" > /log/procID.log
while [ $count != 0 ]
do
timer=`date "+%H:%M:%S"`
echo "$timer" > /log/tcpdump.log
sleep 60
done

I may be doing this all wrong, my expertise is in computer repair / server setups. I don't know a whole lot about UNIX scripting. So if you see a simple way to merge these into a single script please tell me.

In the second script change from overwriting the file ">" to append ">>" and that should do it

Well that solved one problem but created another. Once the timer script timestamps the log the tcpdump script stops writing to it until the timer script is shutdown.

change both scripts so they append the file ">>" if the file does not exist it will create it. I tried in my machine and it worked just fine.

You are indeed correct now I just need to clean up the formatting a bit. Thanks