Subject: dd: document that bs overrides ibs and obs
Date: Wed, 29 Mar 2017 17:04:06 +0100
Package: coreutils
Version: 8.25-2+b1
Severity: minor
Dear Maintainer,
The man page for dd does not define an interaction between bs and its more
specific ibs and obs options. POSIX does mandate that bs, if specified,
shall override ibs and obs. Empirically I have determined that coreutils
dd implements POSIX behaviour, so I should like to suggest the man page
is updated to state that bs overrides ibs and/or obs.
POSIX man page at http://www.unix.com/man-page/posix/1posix/dd/ defines
the three options bs, ibs, and obs as follows:
ibs=expr
Specify the input block size, in bytes, by expr (default is 512).
obs=expr
Specify the output block size, in bytes, by expr (default is 512).
bs=expr
Set both input and output block sizes to expr bytes, superseding
ibs= and obs=. If no conversion other than sync, noerror, and
notrunc is specified, each input block shall be copied to the
output as a single block without aggregating short blocks.
Extracts from the current coreutils man page read as follows:
bs=BYTES
read and write up to BYTES bytes at a time
ibs=BYTES
read up to BYTES bytes at a time (default: 512)
obs=BYTES
write BYTES bytes at a time (default: 512)
I would like to suggest that the explanation is amended as follows:
bs=BYTES
read and write up to BYTES bytes at a time (default:
512); overrides ibs and obs
-- System Information:
Debian Release: stretch/sid
APT prefers stable
APT policy: (900, 'stable'), (800, 'testing'), (300, 'unstable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.8.0-2-amd64 (SMP w/1 CPU core)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages coreutils depends on:
ii libacl1 2.2.52-3
ii libattr1 1:2.4.47-2
ii libc6 2.24-8
ii libselinux1 2.6-3
coreutils recommends no packages.
coreutils suggests no packages.
-- no debconf information
Acknowledgement sent
to Pádraig Brady <[email protected]>:
Extra info received and forwarded to list. Copy sent to Michael Stone <[email protected]>.
(Thu, 30 Mar 2017 02:18:03 GMT) (full text, mbox, link).
Subject: Re: Bug#859021: dd: document that bs overrides ibs and obs
Date: Wed, 29 Mar 2017 19:06:46 -0700
On 29/03/17 09:04, Chris Davies wrote:
> Package: coreutils
> Version: 8.25-2+b1
> Severity: minor
>
> Dear Maintainer,
>
> The man page for dd does not define an interaction between bs and its more
> specific ibs and obs options. POSIX does mandate that bs, if specified,
> shall override ibs and obs. Empirically I have determined that coreutils
> dd implements POSIX behaviour, so I should like to suggest the man page
> is updated to state that bs overrides ibs and/or obs.
>
>
> POSIX man page at http://www.unix.com/man-page/posix/1posix/dd/ defines
> the three options bs, ibs, and obs as follows:
>
> ibs=expr
> Specify the input block size, in bytes, by expr (default is 512).
>
> obs=expr
> Specify the output block size, in bytes, by expr (default is 512).
>
> bs=expr
> Set both input and output block sizes to expr bytes, superseding
> ibs= and obs=. If no conversion other than sync, noerror, and
> notrunc is specified, each input block shall be copied to the
> output as a single block without aggregating short blocks.
>
>
> Extracts from the current coreutils man page read as follows:
>
> bs=BYTES
> read and write up to BYTES bytes at a time
>
> ibs=BYTES
> read up to BYTES bytes at a time (default: 512)
>
> obs=BYTES
> write BYTES bytes at a time (default: 512)
>
>
> I would like to suggest that the explanation is amended as follows:
>
> bs=BYTES
> read and write up to BYTES bytes at a time (default:
> 512); overrides ibs and obs
Done in your name upstream at:
http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=v8.27-15-gc1c558e
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