Mailing the story:

pv (Pipe Viewer) - Shell pipeline element to meter data passing through. pv (Pipe Viewer) can be inserted into any normal pipeline between two processes to give a visual indication of how quickly data is passing through, how long it has taken, how near to completion it is, and an estimate of how long it will be until completion.To use it, insert it in a pipeline between two processes, with the appropriate options.