GNU bug report logs - #14846
doc: dd: improve ibs=BYTES description

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: jidanni <at> jidanni.org
To: bug-coreutils <at> gnu.org
Subject: dd how to skip one byte from reading the man page
Date: Fri, 12 Jul 2013 07:50:59 +0800

If the user tries to figure out how to skip one byte
just from reading the dd man page, and not info,

in order to finally figure out how to do

$ echo abc|dd ibs=1 skip=1
bc

it seems
       ibs=BYTES
              read up to BYTES bytes at a time (default: 512)
should be instead
       ibs=BYTES
              reset the input block size (default: 512)
or something...

Message #8 received at 14846 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: jidanni <at> jidanni.org
Cc: 14846 <at> debbugs.gnu.org
Subject: Re: bug#14846: dd how to skip one byte from reading the man page
Date: Fri, 12 Jul 2013 17:49:58 +0100

On 07/12/2013 12:50 AM, jidanni <at> jidanni.org wrote:
> If the user tries to figure out how to skip one byte
> just from reading the dd man page, and not info,
> 
> in order to finally figure out how to do
> 
> $ echo abc|dd ibs=1 skip=1
> bc
> 
> it seems
>        ibs=BYTES
>               read up to BYTES bytes at a time (default: 512)
> should be instead
>        ibs=BYTES
>               reset the input block size (default: 512)
> or something...

Hmm I suppose a more direct description is more accurate.


BTW, note the skip_bytes flag which can be used to more
efficiently skip odd sizes:

$ echo abc | dd iflag=skip_bytes skip=1 status=none
bc

$ echo abc | strace -e read dd iflag=skip_bytes skip=1 status=none
read(0, "a", 1)                         = 1
read(0, "bc\n", 512)                    = 3
read(0, "", 512)                        = 0
bc

cheers,
Pádraig.

Message #11 received at 14846 <at> debbugs.gnu.org (full text, mbox):

From: Assaf Gordon <assafgordon <at> gmail.com>
Cc: 14846 <at> debbugs.gnu.org
Subject: Re: bug#14846: dd how to skip one byte from reading the man page
Date: Sun, 21 Oct 2018 15:20:06 -0600

tags 14846 notabug
severity 14846 wishlist
retitle 14846 doc: dd: improve ibs=BYTES description
stop

(triaging old bugs)

On 12/07/13 10:49 AM, Pádraig Brady wrote:
> On 07/12/2013 12:50 AM, jidanni <at> jidanni.org wrote:
>>
>> it seems
>>         ibs=BYTES
>>                read up to BYTES bytes at a time (default: 512)
>> should be instead
>>         ibs=BYTES
>>                reset the input block size (default: 512)
>> or something...
> 
> Hmm I suppose a more direct description is more accurate.
> 

Marking as "wishlist".

Patches welcomed.


-assaf

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