dd is a traditional utility for binary data copies

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Exfat - Manjaro Linux - will not mount - [on hold]

I know this might be a big pain but heres the description of the problem i am having... Manjaro linux .0.8.10 linux kernel 3.17.0-1 64Gb microsd formatted to exfat by LG-G3 Android Using a 2.5" ...
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From a sparse file to a block device

I have a system image sparse file which actual size is only a few MBs but the "apparent size" is about 1GB. I'm trying to write it to a block device efficiently (without the holes). Here are some ...
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34 views

losetup /dev/loop0 disappears after some time

at the moment I do some tests with loop devices on Linux/Ubuntu. In a small test script I have the following commands: #!/bin/sh rm testfile.x dd if=/dev/zero of=testfile.x bs=1M count=1200 losetup ...
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How do I know if dd is still working?

I've not used dd all that much, but so far it's not failed me yet. Right now, I've had a dd going for over 12 hours - I'm writing an image back to the disk it came from - and I'm getting a little ...
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3answers
111 views

How can `dd` be used to right-shift data blocks?

Consider a 100MB raw block device as a simple example. That is 204800 blocks of 512 bytes each for a total of 102760448 bytes. The challenge is to shift the first 98MB (200704 blocks) so there is a ...
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1answer
32 views

Can I use dd to quickly resilver a ZFS mirror disk?

My ZFS pool consists of two mirrored disks. I have two more disks which I plan to use for rotating offsite backups. The first backup disk was added to the zpool and has nearly completed resilvering. ...
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1answer
2k 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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how to write dd command to replace backup image of root partition?

I have installed rhel6.5 in my pc. After that I have changed some configurations in file system. now I have taken backup image of /dev/sda1 which is a root partition of 15gb in size using the command ...
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Hard Drive reporting all 1's after parted

So I have a 3TB hard drive /dev/sdc that I am trying to create a partition on. Before this point, I had the issues described below, I transfered the drive to a Windows 7 computer and created a GPT on ...
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4answers
755 views

Why is writing SLOW on raw device, and FAST on filesystem (USB key)?

I have a USB key (PQI U822V-Speedy 32G) 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 ...
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Software RAID10 setup writes small files extremely slowly, is this normal?

I have a software RAID-10 setup on Linux 3.16.6-203.fc20.x86_64, with 1.2 metadata and the default chunk size (512K): $ cat /proc/mdstat md0 : active raid10 sdc1[4] sdb1[0] sdd1[2] sde1[3] ...
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1answer
39 views

mounting partition images made with dd

is there a way to mount and access a single partition on any mountpoint in my filesystem or must I use disk images and mount with offset? I made a partiton image with dd bs=4M if=/dev/sdb1 ...
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22 views

dd over smb to reformat ntfs as ext3

I've been told it's possible to use dd to reformat a portion of a Windows share drive from NTFS to ext3. I'd like to do this to be able to preserve permissions when using rsync for backups, but I ...
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3answers
40 views

Can I backup a 1TB drive onto a 750GB drive?

I want to backup a larger harddrive (1000GB), but sadly, I only have a smaller harddrive (750GB) available. In this particular case, I do not want to copy over the files, I want to backup the ...
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74 views

Write the same file multiple times to one file using dd

I am trying to create large dummy files on a drive using dd. I am currently doing this: #!/bin/bash writeFile(){ #$1 - destination directory/filename, $2 - source filepath $3 - blocksize, $4 - ...
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2answers
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How can I see processes being run by another instance of root on my Beaglebone

I am installing a Raspbian Linux image onto an sd card inserted into my BeagleBone Black. I will use this later in my Raspberry Pi. To do this, I am using the dd command from my MacBook Pro (via ...
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1answer
37 views

hexedit: change number of columns (bytes per line)

I am using hexedit to show/edit disk MBR (512 Bytes, copied with dd). When I open the file, hexedit displays the file as 9 columns, 4 bytes per column (36 bytes per line). That is very unfortunate. I ...
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1answer
64 views

What does the command pkill -USR1 -n -x dd mean exactly?

I am using dd to do a network transfer of a disk image to an sd card on my BeagleBone. Using pkill -USR1 -n -x dd in an ssh connection to this BeagleBone gives me a status update of the transfer ...
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1answer
22 views

How to make dd fail if it invalid skip value is specified?

When I invoke dd with an invalid value for skip it prints an error message and does nothing, but doesn't return with a value different from 0, e.g. $ cd /tmp $ mkdir xy $ cd xy $ truncate -s 2M ...
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393 views

Why is dd not protected against writing on the active disk ?

I use dd a lot. I live in a contant fear of making a mistake one day, for example writing on sda (computer disk) instead of sdb (USB disk) and then erasing everything I have on my computer. I know dd ...
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1k views

How to convert dd disk image to Clonezilla?

I have disk image from VirtualBox, it is a raw image, just like dd makes it, now I would like to restore the system to real machine using Clonezilla. However Clonezilla does not recognize the image ...
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3answers
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can 'dd' be used to clone to a smaller HDD, knowing that partitions will need editing?

I've used dd to clone disks like this: dd if=/dev/sdb of=/dev/sda bs=4096 conv=notrunc,noerror,sync And it's always worked fine. Any and all docs on 'dd' take pains to remind you that the target ...
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2answers
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How to parallelize dd?

I'm currently having trouble with dd invoked with a sparse file as input (if) and a file as output (of) with conv=sparse. dd seems to be using one core of the CPU (Intel(R) Core(TM) i7-3632QM CPU @ ...
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2answers
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why do people use “notrunc” when making an ISO from a DVD?

There are many articles on the web that describe a command-line to make an ISO image from a DVD-Video disc like this: dd if=/dev/sr0 of=mydvd.iso conv=noerror,sync,notrunc I'd like to uderstand why ...
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1answer
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Differences between dd in Mac OS X and Linux

When using Linux (Debian), I often use dd to copy a disk image to an SD card. I have written a script that throws an error if the device file specified in the "of" option is too large. This keeps me ...
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2answers
106 views

dd taking weeks

A few days ago, I got the message "Windows detected a hard disk problem". I got a new hard drive, and booted into Ubuntu using a live USB. I started cloning the failing disk using sudo dd ...
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How do I suppress dd output?

I have a bash script that creates some file using dd. The problem is dd throws a great amount of output that is going to mess with the output of my script. Searching around I've found a solution: dd ...
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1answer
40 views

dd, seek with one block size, write with another block size

Background Info: Copying some .bin files to an SD card (to be read by an embedded device, no filesystem) Commissioning the card requires some segments to be wiped (i.e. zero'd), and others to have ...
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1answer
88 views

Is it possible to use dd to clone only the part of the hard drive which is used?

if only 1/3 of a 300GB hard disk is used. Is it possible to use dd to clone the drive (but only the 100GB that is used)? dd if=/dev/sda of=clone.img
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1answer
109 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, which works with large files? dd works when I move the file contents towards the right, but not if I move the contents ...
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GNU Guix usb-install freezes at GRUB after boot

I wanted to try out the GNU usb install that was released with Guix 0.7. The problem is that when I try to boot from the USB, it freezes, with the word GRUB and a flashing type line. I followed the ...
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129 views

how to use dd to fill drive with 1's

Filling a drive with /dev/urandom seems to be very slow, so I created a file filled with FF: dd if=/dev/zero ibs=1k count=1000 | tr "\000" "\377" >ff.bin I'd like to fill the drive with copies ...
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3answers
353 views

dd write vs read performance

I have recently done some performance tests on a new server (using dd) and wonder why read performance is so much worse than write performance? Shouldn't it be another way around? file size was in ...
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Is this a correct way to back up one big drive to two smaller ones?

I have a pre-fail drive, and while I'm waiting for replacement I am trying to do full back up to two smaller drives. Given that drive is 3TG and ones I have are 1.5 and 2TB, is this a correct way to ...
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1answer
265 views

Partially overwrote /dev/sda, can I recover anything?

I was messing around with my new hard drive, which only contains some personal files, and to check its write speed, I typed: sudo dd if=/dev/zero of=/dev/sda, /dev/sda/ being the new 2 TB connected to ...
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735 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
80 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 > ...
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Is it possible to mount a gzip compressed dd image on the fly?

I like create an image backup for the first time I'm backing up a system. After this first time I use rsync to do incremental backups. My usual image backup is as follows: Mount and zero out the ...
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2answers
267 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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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 ...
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3answers
127 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 ...
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5answers
650 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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106 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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425 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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910 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. ...
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62 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
394 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
3k 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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7answers
1k views

How to write repeated free-form strings to a file, as fast as 'dd'?

dd can write repeating \0 bytes to a file very fast, but it can't write repeating arbitary strings. Is there a bash-shell method to write repeating arbitary strings equally as fast as 'dd' (including ...
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107 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 ...