[Toybox] dd in toybox?

[scsijon]

On 09/07/19 16:56, Rob Landley wrote:
> On 7/8/19 10:41 PM, scsijon wrote:
>> I was wondering if you would consider adding parts of ddfldd
>> (https://linuxx.info/dcfldd/, https://linux.die.net/man/1/dcfldd and
>> http://dcfldd.sourceforge.net/) rather than having just the ordinary dd 'bits'
>> to your dd implementation if possible?
> 
> What specific feature(s) are you asking for?
> 
>> I know it's not new, but the extra
>> operands "pattern, textpattern and errlog" at least seem to be somewhat more
>> than just clearly usefull, with maybe the pair "hash and hashwindow" also if
>> possible.
> 
> Um...
> 
>> dcfldd is a newer version of dccifd, is functionally the same, but in parallel
>> able to calculate checksum using hashing algorithms are MD5, SHA-1 and SHA-2,
>> while it extends partially (by subscription).
> 
> This differs from piping it through sha1sum how? Never having used this, it's
> not immediately obvious how or why to...
> 
>> Or do you have some other way we can deal with these combined
>> functions easily?
> 
> Pipelines? This is why Doug McIlroy suggested the pipe operator somewhere around
> 1973?
> 
>    yes "hello" | dd
> 
>> And as usual, i'll state that i'm not a coder nowadays, just a builder with a 3d
>> perspective outlook, I can't give you a patch, just an idea for someone to work
>> with. :-)}
> 
> Could you give me some usage examples?
> 

ok, this is the usual example given for it,

dcfldd if=/dev/source hash=md5,sha512 hashwindow=1G md5log=md5.txt 
sha512log=sha512.txt \hashconv=after bs=512 conv=noerror,sync split=1G 
splitformat=aa of=image.dd

and all done without external pipe, etc. overheads.

My normal use though, is for fixing and changing formats in .iso  and 
.img files, saves a total rebuild of an iso just to fix a typo, a bane 
in my life at least (if not also for others) when a iso and img.gz are 
just about ready for a release which is why I would like pattern and 
textpattern added.

> Rob
>