Comment 36 for bug 64067

Well, consider that some folks want a GUI-oriented progress bar, and some want
text-only. Some are happy to incur the cost of a curses library, others want
the minimal footprint and are happy with less eye candy. We've hashed out all
of this, over the years, and came to the conclusion that if there is to be any
such thing associated with GNU cp (and mv, and dd, and maybe others, like
install), then the mechanism must be sufficiently generic to work with an
independent program that would be in charge of displaying the progress meter.
Then, the core copying code needn't be polluted with code that some will never
want or use. Here's a proposed implementation from 2004:
http://thread.gmane.org/gmane.comp.gnu.coreutils.bugs/1663