Circular files in linux
I have tcpdump running as a background process, and I have routing daemon needing to analyses some of that output. What would be best for me is to have a log file that tcpdump writes to, which the daemon can analyse when it needs to. However since this is all being done on very small computers, I need to be able to keep the file size to something like 100 - 200 lines as well as update it with new information from tcpdump.
I have looked quite a bit for help on circular files, but I don't know how on earth I could go about creating one on my debian distro.
Have a look at the -W switch
That was very helpful, however I find it writes the raw packet to the file, and I want the routing daemon to read plain ascii output from tcpdump, not the raw packet.