I have made some scripts that I use to monitor CPU temp & load average on a bunch of machines. I would like to monitor network throughput as well, preferably the number of packets sent & received (or maybe it should be bytes instead of packets?) per second, logged as an average once per minute. I looked breifly at ethereal, but I didn't see how to make a non-interactive report (maybe I missed it?). I use gnuplot to make a graph for the entire day, so the prefered output is a number (one for tx, one for rx) that can be catted to a file once per minute as a cron job.

Any suggestions?

try ntop.