Suggestion: A No-write Option, e.g. --scrub.

[Ralph Corderoy]

Hi,

I've just used dd(1) to repeatedly read an SD card until it got all the
way through without an I/O error.  Quite a bit of the run time was
reading what had already been successfully read because I was lazy, or
had a better way to use my time.

It occurred to me that ddrescue(1) would do a better job, but I wouldn't
want a copy created in an output file.  I skimmed
https://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html but
didn't see a way to do this, or a special meaning to an output file of
/dev/null.

A --scrub would be quite handy to read repeatedly until the media's
controller succeeds and re-maps the block internally.

-- 
Cheers, Ralph.