Re: dd patch to output transfer rate, byte count, and time

[Paul Eggert]

address@hidden writes:

> Personally I don't think sending SIGUSR1 is a user friendly interface

I agree.  Also, its implementation isn't portable: it assumes that
stdio is reentrant, which isn't true in general.  This should get
fixed at some point.

But it's not just SIGUSR1.  I think this behavior:

  $ tar cf - . | dd of=/tmp/tape bs=1M
  9+1 records in
  9+1 records out
  10MB copied in 0.071009s (146MB/s)

is far more useful than the previous behavior, which omitted the last one.

Come to think of it, if we wanted to support progress-bar add-ons, the
output line should also contain a full byte count, as that's easier to
parse.  E.g., the output should look something like this instead:

  $ tar cf - . | dd of=/tmp/tape bs=1M
  9+1 records in
  9+1 records out
  10393600 bytes, 0.069786 seconds (10MB copied, 149MB/s)

> So personally I would have just added a --progress option.

Something like that might be nice, but I'd like to see a consistent
interface for dd, cp, mv, etc -- all the utilities that are commonly
used to copy large objects.