Re: [Bug-ddrescue] Appending zeroes by seek is not working

[Antonio Diaz Diaz]

Pavel Roskin wrote:
> I hope you know that dd creates an empty file when it's asked to copy
> zero bytes, and least on GNU/Linux.
>
> dd if=/dev/zero of=foo bs=1M count=0 seek=1

In fact, unless 'conv=notrunc' is given, 'dd' truncates foo to zero 
bytes (or the size specified with 'seek'). And you do not want ddrescue 
to trucate outfile, right?

Your suggestion would also extend outfile when a position is given 
beyond the end of infile, what is not desired either.


> I don't see anything wrong with "Nothing to do", even without "Empty
> domain". Except that both imply that copying data is the main purpose
> of ddrescue and extending the file is a minor preparation job that can
> be omitted if not needed. If "ddrescue" was written with that
> mentality and nobody except me sees that as an unpleasant surprise, I
> guess I should just accept it and use dd for extending files without
> copying.

Right. Ddrescue is designed to copy data as safely as possible in the 
worst conditions, and in particular to only extend or write to the 
output file when there is something useful to copy. I guess dd is the 
right tool for extending files without copying.


Best regards,
Antonio.