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Groups > linux.debian.user > #236752
| From | Michael Stone <mstone@debian.org> |
|---|---|
| Newsgroups | linux.debian.user |
| Subject | Re: Useful use of dd |
| Date | 2021-07-02 14:50 +0200 |
| Message-ID | <CwqMi-4tM-5@gated-at.bofh.it> (permalink) |
| References | <CwoAN-3dZ-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Jul 02, 2021 at 01:26:23PM +0300, Teemu Likonen wrote: >* 2021-07-02 09:49:23+0200, tomas@tuxteam.de wrote: > >> FWIW, I've found something which could be deemed to be an "useful use >> of dd" which somehow bears a hidden symmetry. As a replacement for >> `cat' whenever you need to put a name on the output file. > >For this new subject I will add another use: quickly create empty file >of specific size, for example 5 * 1024 bytes: > > $ dd of=empty obs=1024 seek=5 count=0 For this it is IMO more clear to use truncate: truncate -s 5k empty On Fri, Jul 02, 2021 at 07:31:24AM -0400, Greg Wooledge wrote: >On Fri, Jul 02, 2021 at 09:49:23AM +0200, tomas@tuxteam.de wrote: >> sudo dd of=/etc/hosts oflags=append > >This appears to be a typo for "oflag=append", which is a GNU extension, >not part of the standard POSIX dd. No wonder I didn't know about it. ;-) Because you've been asleep since the 80s when POSIX was relevant? :-D >The bullseye version of GNU coreutils dd also gives a warning message >with this particular flag: > >unicorn:~$ echo g | dd of=foo oflag=append >dd: you probably want conv=notrunc with oflag=append >0+1 records in >0+1 records out >2 bytes copied, 9.141e-05 s, 21.9 kB/s > >Not sure if that's unique to bullseye. But anyway, yes, the warning >is accurate; without conv=notrunc, my test file "foo" got overwritten >with just the "g". It's been like that for more than a decade, sarge in the debian timeline. The warning was added for obvious reasons. :-) (There is a narrow use case for append without notrunc, which is why it's a warning and not a fatal error.)
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Whole Disk Encryption + SSD piorunz <piorunz@gmx.com> - 2021-06-28 17:00 +0200
Re: Whole Disk Encryption + SSD Jochen Spieker <ml@well-adjusted.de> - 2021-06-28 18:00 +0200
Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-28 22:40 +0200
Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-29 00:00 +0200
Re: Whole Disk Encryption + SSD Stefan Monnier <monnier@iro.umontreal.ca> - 2021-06-29 02:00 +0200
Re: Whole Disk Encryption + SSD <tomas@tuxteam.de> - 2021-06-29 09:50 +0200
Re: Whole Disk Encryption + SSD Stefan Monnier <monnier@iro.umontreal.ca> - 2021-06-30 00:50 +0200
Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-30 01:00 +0200
Re: Whole Disk Encryption + SSD Jonathan Dowland <jon+debian-user@dow.land> - 2021-06-29 11:30 +0200
Re: Whole Disk Encryption + SSD piorunz <piorunz@gmx.com> - 2021-06-29 14:10 +0200
Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-30 02:20 +0200
Re: Whole Disk Encryption + SSD David Wright <deblis@lionunicorn.co.uk> - 2021-07-02 05:00 +0200
Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 05:50 +0200
Useless use of "dd" Teemu Likonen <tlikonen@iki.fi> - 2021-07-02 07:50 +0200
Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 09:50 +0200
Re: Useful use of dd [was: Useless use of "dd"] Teemu Likonen <tlikonen@iki.fi> - 2021-07-02 12:30 +0200
Re: Useful use of dd "Thomas Schmitt" <scdbackup@gmx.net> - 2021-07-02 13:00 +0200
Re: Useful use of dd <tomas@tuxteam.de> - 2021-07-02 13:20 +0200
Re: Useful use of dd Teemu Likonen <tlikonen@iki.fi> - 2021-07-02 13:30 +0200
Re: Useful use of dd David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 23:50 +0200
Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 13:20 +0200
Re: Useful use of dd Michael Stone <mstone@debian.org> - 2021-07-02 14:50 +0200
Re: Useful use of dd [was: Useless use of "dd"] Kushal Kumaran <kushal@locationd.net> - 2021-07-02 21:10 +0200
Creation of empty files [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 23:40 +0200
Re: Creation of empty files [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-03 00:00 +0200
Re: Creation of empty files [was: Useful use of dd] Michael Stone <mstone@debian.org> - 2021-07-03 15:50 +0200
Re: Creation of empty files [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-03 23:40 +0200
Re: Creation of empty files [was: Useful use of dd] Michael Stone <mstone@debian.org> - 2021-07-04 06:00 +0200
Re: Useful use of dd [was: Useless use of "dd"] Greg Wooledge <greg@wooledge.org> - 2021-07-02 13:40 +0200
Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 13:40 +0200
Re: Useful use of dd [was: Useless use of "dd"] David Wright <deblis@lionunicorn.co.uk> - 2021-07-02 17:10 +0200
Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 17:40 +0200
Re: Useful use of dd [was: Useless use of "dd"] Gunnar Gervin <dofeelok@gmail.com> - 2021-07-03 09:20 +0200
Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-03 09:30 +0200
Useless use of shell pipelines [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 23:40 +0200
Re: Useless use of shell pipelines [was: Useful use of dd] l0f4r0@tuta.io - 2021-07-03 10:30 +0200
Re: Useless use of shell pipelines [was: Useful use of dd] Greg Wooledge <greg@wooledge.org> - 2021-07-03 15:40 +0200
Re: Useless use of "dd" David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 21:40 +0200
Re: Whole Disk Encryption + SSD David Wright <deblis@lionunicorn.co.uk> - 2021-07-02 17:10 +0200
Re: Whole Disk Encryption + SSD Michael Stone <mstone@debian.org> - 2021-07-02 17:30 +0200
Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 20:40 +0200
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