A common Unix program whose primary purpose is the low-level copying and conversion of raw data.

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1answer
5k views

dd_rescue vs dcfldd vs dd

What are the main differences between dd_rescue, dcfldd, and dd? In what situations would you use one over the other? Why are there three different yet simliar programs?
14
votes
5answers
36k views

How to create VHD disk image from a Linux live system?

Once more, I have to resort at the experts here at SuperUser, as my other sources (mainly Google ;-)) didn't prove very helpful... So basically, I would like to create a VHD image of a physical disk ...
9
votes
7answers
3k views

How can I recover a crashed hard drive?

My hard drive from my MacBook crashed and died hard last week. I replaced the drive with a new one, and installed 10.6/Snow Leopard on it. The old drive is now in a usb enclosure, and I really need to ...
4
votes
2answers
496 views

Recovering Ubuntu after filesystem was overwritten using dd

I had an Ubuntu installation on my laptop, on an encrypted LVM (this was /dev/sda1). I was planning to write an Arch Linux image to my USB drive (/dev/sdc1), following this guide - ...
18
votes
2answers
48k views

creating a bootable USB from command line on linux

I have a CD that's created from an ISO file which I use to install a custom version of Ubuntu via plop linux. The cd works fine but I'd like to use a bootable USB drive instead. I used the command dd ...
6
votes
1answer
251 views

Is it possible to 'instantly' create arbitrary files?

I've seen the following trick to create large, empty files somewhat quickly: dd if=/dev/zero of=test.dat bs=1024 count=1024 However, this still takes some time when creating multi-GB files. I ...
3
votes
2answers
10k views

Rescuing a hdd with bad sectors: dd vs gddrescue

Somewhere on the internets I read that gddrescue is superior to dd at least in terms of being able to distinguish between the amount of disk reads performed on a troubled sector. Is this really the ...
1
vote
1answer
887 views

recover data after using dd command

Hi I have an Iomega HD for mac. I was writing a ubuntu server image to another drive but accidentally selected my 500GB Iomega with my files on it. The command I ran was: sudo dd ...
1
vote
4answers
272 views

Creating an image of my hard drive

I've been thinking of making an image of my laptop's hard drive for backup purposes. What would be the best way of doing this? I know about dd but is there a more user-friendly way, perhaps a GUI ...
19
votes
4answers
27k views

How can I find what /dev my DVD-drive is?

I'm on Mac OS X, have a DVD in the DVD-drive and can look at it in the Finder. I'd like to try to create an iso of it by using the dd command. But to do that I need to know what device to use as an ...
17
votes
4answers
36k views

Why does 'dd' not work for creating bootable USB?

Recently I wanted to create a bootable USB of Linux mint. I found that there was a lot of conflicting advice/experience about whether the 'dd' command could be used to create a bootable USB. I decided ...
21
votes
5answers
22k views

How Do I Find The Hardware Block Read Size for My Hard Drive?

I'm trying to figure out the optimal size for a large copy from my hard drive using dd. I'm trying to figure out what the best blocksize to use it, which I would assume is the hardware block size for ...
10
votes
3answers
20k views

How do I create an MBR on a USB stick using DD command line tool

Okay I'm trying to create a BOOTABLE Windows7 image on a USB key from a Mac running Lion. My image is .iso format. I tried: sudo dd if=/Users/myusername/Win7.iso of=/dev/disk1 bs=1m And this ...
19
votes
5answers
15k views

Why is my /dev/random so slow when using dd?

I am trying to semi-securely erase a bunch of hard drives. The following is working at 20-50Mb/s dd if=/dev/zero of=/dev/sda But dd if=/dev/random of=/dev/sda seems not to work. Also when I ...
6
votes
1answer
2k views

Compressing a file in place - does “gzip -c file | dd of=file” really work?

In the question How can I compress a file on Linux in-place, without using additional disk space?, one answer proposes to simply use gzip -c file | dd of=file I tried it (on Debian Linux), and it ...
3
votes
5answers
1k views

dd producing corrupt ISO images on Snow Leopard (whether invoked from a script or the shell)

Alright, I am probably being an idiot here, but I am writing an ISO-ripping util that is really just GUI slapped on top of dd, and I can't coax the thing to produce non-corrupt ISOs on Snow Leopard. ...
3
votes
3answers
10k views

dd clone hard drive: Input/Output Error though “chkdsk” says OK

I've used dd to clone hard drives before using 'dd' and a live cd, but have run into a problem. The issue: dd fails with an "Input/Output Error" on /dev/sda3 , even though windows "check disk" ...
2
votes
1answer
142 views

DDRescue - Did I do the wrong command which is causing it to take longer then expected

I am running the following command on a 500GB drive: ddrescue --force --direct /dev/sde2 /home/backups/sde2.img sde2_logfile.ddrescue However, the time has been almost 24hrs and all it has done so ...
2
votes
2answers
138 views

Move partition data with dd to the right

I need some help to get a dd command line that is moving my partition blockwise to the right. I stumbled upon an error when using tools to image some pcs and now I need to repartiition those machines ...
5
votes
1answer
3k views

Can I resume an interrupted disk image done with dd?

I am going to reinstall my system and I want to backup it first. There is an 80 GB HDD with Ubuntu and 750 GB HDD on which I want to put image. So, I run a live CD and use dd to transfer my sda to ...
4
votes
1answer
813 views

Can you successfully clone a Mac OS X boot volume directly to another larger volume with ddrescue?

Can you clone a Mac OS X boot volume (specifically a "Mac OS Extended, Journaled" a.k.a. JHFS+ volume) directly to another, larger volume using ddrescue or even dd, and have the target volume end up ...
6
votes
1answer
8k views

Why do we use cp to copy files and not dd? (in unix-derivatives)

For normal file copying in *nix, I've only ever seen people use cp (eg. cp /mnt/mydevice/myfile ~/myfile), but I eventually ran into dd, which appears to do the exact same thing (dd ...
3
votes
1answer
4k views

How do you create and partition a raw disk image?

I need to create a raw disk image for use in a virtual machine, but I need to create the partitions before creating the file system or installing the operating system. Can anyone describe a process ...
3
votes
3answers
7k views

Cloning an SD card onto a larger SD card

I'm using Ubuntu 12.04. I have an old 4GB SD card, and have just bought a new 16GB SD card. I would like to copy everything from my old 4GB SD card onto the new 16GB SD card. I was afraid that the ...
3
votes
3answers
386 views

Backing up to smaller drive

In a few hours I'll have a new 500GB Sony laptop, filled with the usual Sony rubbish which I'll promptly be replacing with Ubuntu or Crunchbang or something. However, first I want to make a full clone ...
2
votes
1answer
212 views

What happens if dd encounters errors while output of dd is being piped to gzip?

Suppose that dd if=/dev/sda bs=100M | gzip -c > somefile.img.gz is done. If errors occur in dd, do I get to see error messages in terminal, or do they get ignored? Also, suppose that dd ...
1
vote
2answers
429 views

dd - just copy partitions

I have a SanDisk Extreme SD card contaning my Homeserver runing on the RaspberryPI. I want to move this sytsem to another 4GB SD card using dd. But unfortunaltely when I make an image via dd it has ...
1
vote
1answer
797 views

Why does my dd backup of MacBook OS X fail to boot upon restore?

I created a backup of a MacBook hard drive (WD2500BEVS-88US) by hooking it up as a secondary drive on my linux system (Ubuntu 10.10). I used the following command: sudo dd if=/dev/sdc ...