Shell Programming and Scripting

I want a script that would do as:-

a) gives me packet capture account for each time it runs.
b) be able to run at a particular time for specific period time duration (1 min).
c) for each time it runs it saves the time / day.

Is there a way where i can capture the details as seen in the screen shot below where is says "packets captured"



I would appreciate if i can get help over this.So far in what i tried I'm able to get packets information (raw) like in raw dump format. I;m particular interested in knowing its count.

Thank you

seems homework. Give you some hints.

Code:

1. tcpdump  |grep "packers captured" 
   tcpdump  |awk '/packers captured/{print $1}' 
2. set by cronjob
3. man date

Code:

tcpdump -c 4 i eth0 | awk '/packets.captured/ {print $1}'

As i do this on command line i'm getting nothing on screen ?