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bug#15680: dd: suggest iflag=fullblock ... but only if count > 1
From: |
Pádraig Brady |
Subject: |
bug#15680: dd: suggest iflag=fullblock ... but only if count > 1 |
Date: |
Tue, 22 Oct 2013 10:25:49 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 |
tag 15680 notabug
close 15680
stop
On 10/22/2013 07:47 AM, Bernhard Voelker wrote:
> dd(1) issues a nice warning about short reads ...
>
> src/dd if=/dev/random of=sample bs=1000 count=2
> src/dd: warning: partial read (128 bytes); suggest iflag=fullblock
> 0+2 records in
> 0+2 records out
> 256 bytes (256 B) copied, 0.000423371 s, 605 kB/s
>
> ... but only if count was > 1:
>
> src/dd if=/dev/random of=sample bs=1000 count=1
> 0+1 records in
> 0+1 records out
> 128 bytes (128 B) copied, 0.000270231 s, 474 kB/s
>
> Is this by intension or an off-by-one?
> I'd like to provide a patch in the latter case.
The various cases for warning were disucussed at:
http://bugs.gnu.org/7362
Also I mentioned this particular case with count at:
http://bugs.gnu.org/9734#18
Copying from there...
"Note the particular case where count=1 is not warned about,
as with a single read, one doesn't know if we're just at EOF.
Also it's probably a quite common idiom to, consume available data
up to $bs bytes."
thanks,
Pádraig.