Add a new command to dd(1): msgfmt. The command modifies the
output of the information summary returned by dd(1). This can be used
to specify messages in a more usable (or parseable) format like
human-readable values.

My intent is to re-use this for building image files and quick I/O
benchmarking.

Reviewed by tsutsui@ on tech-userlevel. See also
http://mail-index.netbsd.org/tech-userlevel/2010/12/03/msg004179.html

Some examples:

$ dd if=/dev/zero of=/dev/null bs=1m count=1 msgfmt=human
1+0 records in
1+0 records out
1048576 bytes (1,0 MB) transferred in 0.001 secs (1048576000 bytes/sec - 1,0 GB/sec)

$ dd if=/dev/zero of=/dev/null count=1 msgfmt='
> <speed>%E</speed>
> <time>%s</time>
> <bytes>%b</bytes>
> '
<speed>500 KB/sec</speed>
<time>0.001</time>
<bytes>512</bytes>