dd is an utility which is primarily used for low-level copying of data from storage devices.

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6 views

Is dd able to overwrite parts of a file?

I have a 1TB big file (disk-image from a damaged drive) and a 1.3MB small file (beginning of a disk-file). Using the contents of the small file, I want to overwrite portions of the big file. That is, ...
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1answer
31 views

How to use pv with dd?

I'm trying to use dd with pv to write an iso to a usb drive. I did: iso="myiso.iso"; dd if="$iso" bs=1M | pv --eta --size $(ls -l "$iso" | awk '{print $5}') --progress --bytes --rate --wait > ...
2
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2answers
38 views

dd to clone to smaller sdcard

One of my Raspberry Pi's is using a 4GB SDcard for the root/boot filesystem. As seen when mounted on another system: Disk /dev/sdc: 3904 MB, 3904897024 bytes 121 heads, 62 sectors/track, 1016 ...
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3answers
58 views

Full DD copy from hdd to hdd

UPDATE: 2 This seems a lot better than before (Thanks to Groxxda for the suggestions): sudo dd if=/dev/sdb bs=128K | pv -s 3000G | sudo dd of=/dev/sdc bs=128K ETA is about 9 hours for 3TB, whereas ...
2
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3answers
97 views

Why is dd running forever on a 8 GB drive

I have a filesystem handled by ZFS and it's about 8 GB. I tried to zero out the filesystem by running: dd if=/dev/zero of=/EMPTY bs=1M | true rm -f /EMPTY And normally on an ext4 filesystem, it ...
10
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5answers
600 views

Is it safe to take the drive image of the current working drive?

I have to backup my hard disk. I want to use dd and put the image on an external hdd. Can I do this using dd from the OS that resides on the hdd itself or do I have to boot from another device, for ...
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1answer
31 views

DD with a specific pattern

I was watching this Defcon video and around 4:30 he shows a custom pattern of drive wiping — the drive is filled with a constant text pattern. Whether he is joking or not, is this possible? How would ...
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3answers
382 views

1:1 copy with dd

I need to get a copy of an HDD that is a real 1:1, I mean not just the filesystem but also the geometry and the partition table and everything in between. if I'll just use dd if=/dev/sdb ...
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2answers
50 views

`dd` to specific location [closed]

dd is a great tool for copying and conversion. Is there any way by dd (or by any other way), to dump the first few bytes from a file to an unmounted partition? Something like this: dd if=hda2.pbr ...
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2answers
50 views

dd: 'bs', 'count' & 'seek'

I've read many guides and forum posts describing how to use dd, but one thing I've noticed is that people always use different values for the 'bs=', 'count=' and 'seek=' switches. Please can someone ...
3
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1answer
117 views

How to use SSH to make a dd copy of disk A from host B and save on disk B?

I want to make remote backups from disk A at will using SSH from computer B. I want to save the backups to disk B. How can I do this? I've tried using $ ssh hostname@my.ip.add.ress "sudo dd ...
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2answers
63 views

live dd over a mounted read-only root partiton

I'm trying to conceive a firmware update mechanism for a Linux-based embedded system without an additional initrd/initramfs/whatever. From within the running system which has a read-only mounted root ...
4
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3answers
72 views

Can I overwrite LUKS partition with it's decrypted content?

I have HDD with my data (partial backup of most important data available on other HDD), currently it's formatted as Ext4 over LVM over LUKS. I want to remove LUKS layer, but reformatting and data ...
2
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2answers
23 views

Backing up a partition

I am pretty new to linux. I mostly started learning after I purchased a couple of Raspberry Pis. I like to make backups of my images as I have often made the mistake of corrupting my data :). ...
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4answers
153 views

dd remove range of bytes

Given this file $ cat hello.txt hello doge world I would like to remove a range of bytes to end up with this $ cat hello.txt heorld I would like to do this with dd if possible. The reason is ...
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2answers
49 views

How to unpack dd file on Windows? [closed]

Is it possible to unpack files created with linux dd tool on Windows? I have tried that tool http://www.chrysocome.net/dd, but it crashes under Windows 7. Any ideas?
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1answer
80 views

dd and rm -r commands

For me, the following commands do exactly the same thing: dd if=/dev/zero of=/dev/sd1 dd if=/dev/null of=/dev/sd1 rm -r /dev/sd1/* meaning, the result of their application is the same. Or least, ...
4
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1answer
99 views

What does this dd command do exactly?

I have the an embedded device with this SD card: [root@(none) ~]# busybox fdisk -l Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes 4 heads, 16 sectors/track, 121008 cylinders Units = cylinders of 64 * ...
4
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1answer
91 views

Backup of a ubi file system with dd?

A have a root file system (file system - image containinf folder structure and content) on a flash drive. The flash drive uses UBI as the underlying file system file system - the way the data blocks ...
5
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1answer
194 views

Writing raw images safely to USB sticks

Trying lots of different linux, on all kinds of hardware I find my self typing commands like this quite often: sudo dd if=xubuntu-13.10-desktop-amd64.iso of=/dev/sdc bs=10240 Needless to say, ...
2
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4answers
276 views

Why is writing so slow on raw device, and so fast on filesystem (USB key)?

I have a USB key that I am trying to benchmark quick'n'dirty on Linux. I'm testing write bandwith. dd on raw partition I created a partition starting at sector 2048, then did a 4 GB sequential ...
3
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3answers
171 views

how do I do this: dd if=coolstuff.iso of=(ssh kev@mypi )

the card reader on my laptop doesn't want to work. can I use dd (or some other tool) to write an image to a networked disk. I am trying to replace one raspberry pi distro with another. The SD card ...
4
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2answers
251 views

Create random data with dd and get “partial read warning”. Is the data after the warning now really random?

I create a 1TB file with random data with dd if=/dev/urandom of=file bs=1M count=1000000. Now I check with kill -SIGUSR1 <PID> the progress and get the following: 691581+0 Datensätze ein ...
11
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3answers
541 views

Read the middle of a large file

I have a 1 TB file. I would like to read from byte 12345678901 to byte 19876543212 and put that on standard output on a machine with 100 MB RAM. I can easily write a perl script that does this. ...
2
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1answer
65 views

Equivalent of memmove on files: copy a range of bytes to an earlier position

What is an equivalent of memmove on files with the same input and output file? dd works when I move the file contents towards the right, but not if I move the contents left, since there's no handling ...
2
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1answer
45 views

dd command lost partition

When I used to image my USB, I used the dd command and saved that image to my Hard Disk my USB = sdb1 (4 GB) My partation = sda5 (775 GB free space) dd if=/dev/sdb1 of=/dev/sda5 operation ...
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2answers
145 views

How to write an alias function to make dd show progress bar?

According to this article, by replacing: $ dd if=/dev/sda of=/dev/sdb [additional options] with: $ pv -tpreb /dev/sda | dd of=/dev/sdb [additional options] one can augment the default dd ...
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2answers
67 views

dd command: Finding read/write throughput of a flash/SD?

I am running petalinux from sd card. And trying to find data copying rate from Sd card and from QSPI flash that is there on the Xilinx Zynq board. As suggested here , I am doing like this: ...
2
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1answer
70 views

How use tune2fs in with dd?

In this tutorial is written To regain unique UUIDs, use tune2fs /dev/sdbX -U random on every partition. Ok, but how can I use it with this command? dd if=/dev/sda of=/dev/sdb bs=4096 ...
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1answer
144 views

Why does a disk clone using dd take up more space on the target than the source image?

I'm doing some Android development on Ubuntu 11.10. I'm building a set of SD card and eMMC card Android images using a Bash script. Due to Android's idiosyncrasies, I have several file system images ...
2
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2answers
134 views

How to backup a running system?

I have a running Linux system, and I'd like to have a full backup of it using dd, which, in my limited knowledge is the only tool every system has. The distro doesn't matter mainly because I should ...
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0answers
30 views

For what are disk signatures being used for by GNU/Linux (distributions) / grub?

I am talking about disk signatures in context of the MBR. The area from 441 to 445 bytes. For what does the GNU/Linux kernel, GNU/Linux distributions usually use disk signatures for? I only found ...
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1answer
750 views

Copy MBR and boot partition to a smaller disk

I'm using a 32GB SD card for my raspberry pi. I have successfully transferred the operating system (Archlinux ARM) to a usb harddrive. Which means that I only need the boot partition on the SD card. ...
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1answer
77 views

How to change the disk signature of a raw image?

I am talking about disk signatures in context of the MBR. The area from 440 to 444 bytes. Let's say I got a bootable raw image (bootable in a virtual machine). How can I set the disk signature to a ...
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1answer
298 views

SSH remote backup script

I am trying to backup a remote server to my machine. I am trying something like ssh user@ip "dd if=/dev/sda" | dd of=~/backup.img But that obviously doesn't work. Other variants that don't work. ...
2
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2answers
510 views

How to clean journals in ext3/ext4 filesystem? [closed]

Some preamble: I'm taking bitwise copy of disk devices (via dd command) from twin hosts (i.e. with the same virtualized hardware layout and software packages, but with different history of usage). To ...
6
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4answers
2k views

'seek' argument in command dd

Can some explain me what is happening in the following lines? dd if=/dev/urandom bs=4096 seek=7 count=2 of=file_with_holes especially seek part is not clear Man pages says : seek=BLOCKS ...
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2answers
61 views

Debian: Create compressed Harddrive for copy

On my Debian system I have a box with certain configuration settings that I like but I've had to change them continuously. There have been times that I've gotten into a some-what irreversible ...
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0answers
284 views

How to restore a DD image file in my primary disk on new debian server

I have a dedicated Debian server at Online.net and I want to change the server by a more powerful (always Debian OS). For that, I have made an image on my old hard disk with this command: dd ...
3
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1answer
96 views

dd can't see partition but cfdisk and GParted can

I am working with an external HDD and trying to backup a logical partition within an extended partition using dd like this: sudo dd if=/dev/sdb6 of=partition6.dd it returns: dd: opening ...
5
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1answer
104 views

Partitions same size but different block [closed]

I tried to backup my partition using dd on another disk and I created a partition of the same size. When I finished the copy I had problems mounting the partition since I got bad geometry: block ...
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0answers
107 views

dd primary partition slow transfer rate

Can someone explain me why if backup ,using dd, a primary partition to a primary partition on other disk the transfer rate (MB/s) is significantly slower compared to the the rate I have if the ...
0
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3answers
138 views

bit-wise complement with dd?

When secure erasing a disk, how can I do a "bit-wise complement" with dd? (or with other UNIX tools?)
1
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1answer
30 views

Backup 'empty' parts of disk drive

I have a USB drive which has around 7MB of 'empty' space at its beginning. The first partition in MBR starts at 8225kB, according to Parted. How can I back up this space using something like dd? ...
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1answer
39 views

dd behavior, default writing and partitions

I am confused about the behavior of dd. Say we have some SD card called /dev/foo and this card has partitions /dev/foop0 and /dev/foop1. Using dd, I can set the of argument to /dev/foo and dd won't ...
2
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2answers
64 views

Backing up a partition: doesn't reflect the status properly

With an intent to check how backing up files/filesystems works, I created 3 part itions sda9, sda10 and sda11. Please see the structure below. (Please ignore sda10 for now as I have already run ...
3
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1answer
162 views

Attempt to test corruption of ZFS filesystem using dd fails

I'm trying to test error detection and recovery on a system with recently installed ZFS. I deliberately overwrite the start of one of the disks with dd but can't force any errors to be detected. Can ...
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1answer
116 views

Filesystem not showing correct size in Mac OSX

I installed a new HDD and transferred my old data to it by using dd on my old HDD and then dd again to the new HDD. However, when booting from the new HDD, it does not recognize the new, larger disk ...
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2answers
166 views

Hard disk drive disappeared

Yesterday I performed a hard-reset while Linux was booting. This led to a hard issue with the HDD (UNC while recovering journal). I had to use ddrescue instead of dd because dd crashed on I/O error. ...
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2answers
394 views

How to write to SD card with dd command?

Having some trouble with writing to my SD card, burning NOOBS (New Out Of Box Software) software to my SD card for Raspberry Pi. Attempted to use the following command as root: # dd bs=1M ...