Re: Some help with dd backing up into an iso

From	David Wright <deblis@lionunicorn.co.uk>
Newsgroups	linux.debian.user
Subject	Re: Some help with dd backing up into an iso
Date	2017-03-07 16:20 +0100
Message-ID	<tip47-X4-37@gated-at.bofh.it> (permalink)
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On Tue 07 Mar 2017 at 10:55:01 (+0200), Teemu Likonen wrote:
> tomas@tuxteam.de [2017-03-07 09:35:06+01] wrote:
> 
> > dd comes in handy whin you know how much to copy. So this idiom makes
> > sense
> >
> >   dd if=/dev/zero of=lotsofnull bs=1024 count=1024 # copy 1M of zeros
> 
> That particular thing can be made faster without transferring any data:
> 
>     $ dd obs=1M count=0 seek=1 of=file
>     0+0 records in
>     0+0 records out
>     0 bytes (0 B) copied, 1,1289e-05 s, 0,0 kB/s
> 
>     $ ls -lh file
>     -rw-r--r-- 1 dtw dtw 1,0M 2017-03-07 10:52:14 file

In which case, why did you write:

"I don't know about you but many people seem to think that dd is some
kind of special tool for reading and writing block device files. But
after all the devices are just files that can be read with normal
commands like cat or cp."

Those clunky parameters you've used explain one of the reasons
for its being special. Here's another: the OP could have ascertained
how long the (reckless) second copy was going to take by typing
kill -USR1 <pid-of-dd>   to see how much had been copied so far.

Cheers,
David.

Thread

Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-07 01:20 +0100
  Re: Some help with dd backing up into an iso Michael Lange <klappnase@freenet.de> - 2017-03-07 02:10 +0100
  Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-07 06:10 +0100
    Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-07 07:00 +0100
      Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 09:00 +0100
        Re: Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-07 18:30 +0100
          Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 20:20 +0100
            Re: Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-08 05:00 +0100
              Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-08 07:00 +0100
              Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-08 12:10 +0100
                MBR partitioning, and content after partition table but before first  partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-09 06:50 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Felix Miata <mrmazda@earthlink.net> - 2017-03-09 08:00 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-10 06:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-10 10:00 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-11 07:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-13 10:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-14 04:40 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David <bouncingcats@gmail.com> - 2017-03-14 11:40 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-15 03:50 +0100
                Re: MBR partitioning, and content after partition table but before  first partition The Wanderer <wanderer@fastmail.fm> - 2017-03-14 13:00 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-15 04:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Andy Smith <andy@strugglers.net> - 2017-03-15 04:40 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-15 13:00 +0100
                Re: MBR partitioning, and content after partition table but before first partition "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-09 08:30 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-09 15:40 +0100
    Re: Some help with dd backing up into an iso Teemu Likonen <tlikonen@iki.fi> - 2017-03-07 09:30 +0100
      Re: Some help with dd backing up into an iso <tomas@tuxteam.de> - 2017-03-07 09:40 +0100
        Re: Some help with dd backing up into an iso Teemu Likonen <tlikonen@iki.fi> - 2017-03-07 10:00 +0100
          Re: Some help with dd backing up into an iso <tomas@tuxteam.de> - 2017-03-07 10:10 +0100
          Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 16:20 +0100
      Re: Some help with dd backing up into an iso Jonathan Dowland <jmtd@debian.org> - 2017-03-07 11:10 +0100
      Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-08 06:00 +0100
  Re: Some help with dd backing up into an iso Mark Fletcher <mark27q1@gmail.com> - 2017-03-07 12:10 +0100
  Re: Some help with dd backing up into an iso Eduardo M KALINOWSKI <eduardo@kalinowski.com.br> - 2017-03-07 14:50 +0100
  Re: Some help with dd backing up into an iso Elimar Riesebieter <riesebie@lxtec.de> - 2017-03-07 15:20 +0100
  Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 16:20 +0100
    Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 18:10 +0100
      Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 19:00 +0100
        Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 20:30 +0100
          Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 21:30 +0100
            Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 22:10 +0100
              Re: Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-08 18:30 +0100
                Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-08 19:20 +0100

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