Informations about pipe data stream

The tool pv is part of debian, use package pv:

dd if=/dev/sr0 bs=2M | pv -s 8G | dd of=film.iso bs=2M

So, the 8G is uses for the progress.

The tool pipebench write some informations to stderr.

cat /dev/urandom | pipebench | cat - > /dev/null
h00m04.27s:   49.21 MB   11.71 MB/second (Sat May 13 12:42:41 2017)

Cpipe copy from stdin to stdout and measure the time to read and fill the buffer. You get some statistics to stderr.