Filter wireshark output

Hi

I have a wireshark file saved (from my network) and I have to analyze the flows inside it.
The problem is that i have to analyze not the complete file (60.000 pkts!) but just a subset of it.
In other words i have to sample the wireshark.file.dump and for example from 60.000 pkts take randomly just 6.000 pkts.
Wireshark allows you to select or mark same pkts but by hand!!!! (very long time)
Is there any filter to build in order to take randomly just a part of the complete file?
Or is there any other tool that can analize libpcap file and take a subset?

thx in advance

Dedalus

alternatively u can write your own code for it using libcap library. Should not be that difficult. Do some research.

Hi Neminath

your advice is what i'm trying to do. I'm near the end. I'm using a small software that sniff pkts and I've added a randon counter in its callback function, in order to analize some pkts and skip the others.
I'm still testing it but seems like work.
Thanks

D.