Пакет pv: Информация

pv - Pipe Viewer - is a terminal-based tool for monitoring the
progress of data through a pipeline. It 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.

Additional support is available for multiple instances working
in tandem, to given a visual indicator of relative throughput
in a complex pipeline.