Re: [ANNOUNCE] GNU fileutils 4.1

[Matt Schalit]

Paul Eggert wrote:
> 
> > Date: Wed, 23 May 2001 18:15:08 -0700 (PDT)
> > From: Dave Dittrich <address@hidden>
> 
> > > I'm not sure, though, that dd is the right place for this; perhaps it
> > > would be better to have a separate tool?  dd tends to suffer from the
> > > kitchen-sink problem.  Maybe it's better to put this into md5sum
> > > instead?
> >
> > md5sum just reads stdin and checksums it.  It doesn't have any of the
> > other features of dd, like byte swapping, alternate output blocking
> > for efficiently filling streaming media buffers, etc.
> 
> But if you add one simple options to md5sum to control the location of
> the checksum output, and to make a copy to standard output, you can
> get all the above.  For example, you could do the following:
> 
>    dd if=/big/input/device ibs=whatever |
>    md5sum -C checksum.txt |
>    dd of=/big/output/device obs=whatever
> 
> where '-C FOO' means "put a copy of the checksums in FOO and output a
> copy of the input to standard output".



I think you snipped out and are not addressing the
essential point of his method which a gave a checksum
on every byte so that one bad byte could not invalidate an
entire hard drive.

I don't know where you get your md5sum.  I have
the latest GNU textutils installed and that

      md5sum --version == 2.0.13

and I don't have and -C filename.txt option.


I think your example would compute only one checksum,
but I can't check, so why not tell us, hmmmm?

Regards,
Matthew