dd is a traditional utility for binary data copies

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8GB USB disk listed at only 512B or 10MB?

I made an Arch Linux ISO USB drive, and I'm trying to restore it using the directions from the Arch Linux wiki. After running: $ sudo dd count=1 bs=512 if=/dev/zero of=/dev/sde && sync ...
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1answer
33 views

Compare two files, while overriding second file's size

I am trying to verify a backup that I made using the following command: dd if=/dev/sda of=/dev/sdc2 I backed up the contents of /dev/sda (internal hard drive) to /dev/sdc2 (external backup drive, ...
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0answers
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Restore errors: “bad header/extent: invalid magic - magic 1701”

I'm testing these instructions to restore a backup image to an Intel Edison from a previous .img image. The backup line was: dd if=/dev/mmcblk0 of=sd/ubilinux_image.img I removed a file (to see if ...
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2answers
127 views

Why is dd reading from and writing to the same disk?

I've been using dd in Linux to overwrite an external USB hard drive. When I use the default block size of 512 bytes, with this command: # dd if=/dev/zero of=/dev/sdb throughout the whole ...
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3answers
375 views

Copy content from files X and Y to create file XY but XY content is all lowercase

What's the right command to copy the content from file X and File Y to create a new File XY with all letters being lowercase?
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104 views

dd speedup by async reads/writes

I was copying an SSD to an identical one today: dd if=/dev/sda of=/dev/sdb bs=4M They were connected by a SATA cable. While stracing dd I noticed that it was doing the "naive" thing: read 4M from ...
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1answer
155 views

How does cat 'know' the optimum block size to use?

From reading this, it seems that when copying data to a different hard drive, cat automatically uses the optimum block size (or very near it). I wonder how it determines the optimum block size, and ...
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3answers
204 views

Using dd to clone a disk while mounted - risks?

I want to clone a hard disk using dd. Because I want to keep a process on the machine alive continuously, I would like to do this while the filesystem is still mounted. I understand this is not the ...
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1answer
36 views

How to recover a node/content from a tarfile that's been overwritten

Disclaimer: I'm not very good at writing questions, and mine is a very specific scenario. So I'm just going to jump straight into the situation: I was browsing my filesystem, and somehow managed to ...
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1answer
60 views

Pretty print output of “kill -USR1”-ing dd

When dd is done it prints a three line summary about the number of read and written segments, the total size and average writing speed. While it does its work, dd is awfully quiet. Not too long ago ...
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1answer
89 views

USB key does not show up in /dev

We use a USB key system that are contain license files and are provided to unlock proprietary software that we used. The USB drives are small however and get lost easily, so I thought I'd clone them ...
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3answers
391 views

How do I DD over the network to an external HD?

I'm trying to clone a hard drive on my raspberry pi which is on the same network to an external harddrive of the computer I'm currently on. However I'm having issues piping the command correctly. I've ...
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2answers
76 views

Faster way to DD?

I am trying to DD a raw file to an SSD from a spin usb spin drive. I have tried compression (but it obviously has to expand before it can copy). I have watched the details of the arm7 gb ram device... ...
2
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1answer
313 views

How to fix BTRFS superblock error after resize/shrink (BTRFS: couldn't get super buffer head for bytenr 274877906944)

BTRFS RAID1 array with 2 500 GB hdds, no errors. This is the root filesystem, so there are 3 partitions on each drive: 1 = /boot (ext4), 2 = / (btrfs), 3 (swap) /boot is ext4 because upgrading the ...
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3answers
858 views

What does the two numbers mean respectively in dd's “a+b records” stats?

The first 2 lines in dd stats have the following format: a+b records in c+d records out Why 2 numeric values? What does this plus sign mean? It's usually a+0, but sometimes when I use bigger block ...
1
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1answer
94 views

How to prevent dd from freezing my system?

I want to fill the free space on my hard drive with a command like that : # dd if=/dev/zero of=z but it causes GNOME to freeze regularly for a few seconds. Even the mouse cursor is affected. How ...
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2answers
1k views

How to backup and restore to different hardware in Linux? [duplicate]

I am running Fedora 22 on a Dell Laptop. I plan on migrating to a desktop soon which will also run Fedora 22. What is the best way to go about backing up and restoring my laptop configuration to the ...
1
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1answer
41 views

Cloning and remounting sd card

I have a micro sd card that contains these partitions: Disk /dev/sdb: 29,7 GiB, 31914983424 bytes, 62333952 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / ...
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2answers
2k views

How to fix this I/O error on SD card?

EDIT: I tried with gparted, it didnt work. i found a SDFormatter, tool for windows that did the full erase. I have a SD card and want to install debian onto it. The dd process takes about 45 ...
1
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1answer
573 views

The dd command fails with an “Input/output” error while burning a USB stick

This question is somewhat related to the previous question I asked regarding the dd command, The dd command isn't appear to accomplish anything. I'm trying to burn the Ubuntu operating system ...
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3answers
88 views

The dd command isn't appear to accomplish anything [closed]

I'm currently trying to burn the Ubuntu operating system onto a USB flash drive of mine, so I can boot onto Ubuntu with my Chromebook. In order to do this, I executed the following dd command: sudo ...
2
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2answers
106 views

HDD cloning and non-matching checksums

I've been trying to clone a 1Tb HDD to a 1Tb SSD following the instructions here. I tried cloning it several times with both dd (painfully slow) and cat (far quicker) but when I came to do checksums ...
2
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1answer
163 views

Accidentally ejected sd card physically while dd

Full cat /proc/partitions + lsblk + fdisk -l output is here: http://pastebin.com/jYCCmwsU I just bought my new class10 16GB SDCard and I started to restore the Raspbian system for the Raspberry with ...
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2answers
390 views

HDD image file checksum does not match with device checksum

I have a 660297728 byte HDD image with MD5 hash f5a9d398e974617108d26c1654fe7bcb: root@T42# ls -l image -rw-rw-r-- 1 noc noc 660297728 Sep 29 19:00 image root@T42# md5sum image ...
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1answer
112 views

How can I zero the unused blocks on my filesystem in order to minimize the compressed disk image size? [duplicate]

If I dd my disk and compress the image with lzma or lzo the image is still big. The partition is 10GB used, 90GB available. But the image still around 20GB. I believe that is because I have copied ...
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1answer
102 views

change tape on the fly script

I have to write 17 Tb to tape: ssh some_host 'tar -cz /' | dd bs=20b of=/dev/tape of course 17 Tb doesn't fit to one tape so I need automatically change it when "no room" error occurs. I have ...
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2answers
77 views

How to redirect dd to pv? [duplicate]

This is my dd command which I need to modify: dd if=/tmp/nfs/image.dd of=/dev/sda bs=16k Now I would like to use pv to limit the speed of copying from NFS server. How can I achieve that? I know ...
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2answers
221 views

Can I mount a partition from a full drive image? [duplicate]

Note: While I agree that this question basically is a duplicate of the above question, I feel @alienth's answer (below) is more concise, so I suggest you take a look at it before going to the other ...
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2answers
155 views

Why is my dd slow when the blocksize is small?

According to articles on the web, mount with nobarrier will speed the disk up: Write small blocks of data to img (with barrier): SLOW # dd if=/dev/zero of=xfs.img bs=1024 count=20000 # mkfs.xfs ...
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2answers
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How do I Capture dd command output

I have a test script, which is used to estimate the filesize for a particular oracle export dumpfile. Content of the script is: mknod exp.pipe p dd if=exp.pipe of=/dev/null bs=1024 & exp ...
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5answers
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How to ignore write errors while zeroing a disk?

Say you want to zero-out a failing hard disk. You want to overwrite as much as possible with zeros. What you don't want is: the process aborts on the first write-error. How to do that? AFAICS, plain ...
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2answers
119 views

Creating a large file with random content: short-cut by copying?

Assume I want to create a large encrypted drive stored in a file using cryptsetup, the first step is to create a random file, assume this should be of size 3T: dd if=/dev/urandom of=$FILE bs=1G ...
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2answers
693 views

restore dd cloned sd card (No space left on device)

I used this command sudo dd bs=4M if=/dev/sdb1 | gzip > /home/username/image`date +%d%m%y`.gz to clone my 32gb sd card (there was linux installed for odroid U3) now I have tried to restore it on ...
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19answers
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What is the fastest way to send massive amounts of data between two computers?

This is a situation I am frequently in: I have a source server with a 320GB hard-drive inside of it, and 16GB of ram (exact specs available here, but as this is an issue I run into frequently on ...
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1answer
46 views

DD to a bigger partition

So I made a backup of /dev/sda1 (NTFS) using: sudo dd if=/dev/sda1 conv=sync,noerror bs=64K | gzip -c >/media/My\ Book/backup/Root20131215 In the meantime I increased the size of /dev/sda1 to ...
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1answer
455 views

Can I uncompress a zip file containing a disk image and then save that to an SD card all in one step?

I am under the following restrictions: I have a 1.0 GB .zip file on my computer which contains one file, a disk image of raspbian. When uncompressed, this file is 3.2 GB large and named ...
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2answers
858 views

Is it better to use cat, dd, pv or another procedure to copy a CD/DVD?

Background I'm copying some data CDs/DVDs to ISO files to use them later without the need of them in the drive. I'm looking on the Net for procedures and I found a lot: Use of cat to copy a ...
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0answers
57 views

testdisk foremost dd photorec after math help needed

Did i ask this question in the wrong place the first time? http://superuser.com/questions/957845/how-can-i-efficiently-view-validate-delete-1m-files-from-data-recovery I made such a long post about ...
0
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1answer
41 views

Broken disk size after incomplete dd operation

Once I was writing an ISO image into my USB disk using dd, I mistakenly pulled it out, and now it has only 10 MB of size. The correct size is 32 GB. Note that this smaller size is for the whole USB ...
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67 views

Write shrunken .img file to device file

I have a backup image of a device file /dev/sda3 that I created using: dd if=/dev/sda3 of=~/sda3.img. The image is very large, so I have re-sized it to remove empty space. My question is can I ...
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2answers
2k views

Interpreting dd Input/Output error

I tried to copy /dev/Storage/Storage (an LV under LVM) to an image file using a dd | pv | dd pipeline. dd reported an error, and I want to know whether dd finished copying my disk or stopped due to ...
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29 views

Backup full drive structure, skipping one partition content

I need to backup laptop drive. But in fact what matters is not data as in my data files kept on laptop but all systems, settings, lvm and in general whole disk structure - partitioning, UUIDs, LUKS ...
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3answers
382 views

Does dd copy everything, including all metadata and all “empty” blocks

Suddenly something was messed up with my partitions, or just one partition. I have a default Ubuntu installation, on a Kingston SSD, with the root file system encrypted with LUKS, (using AES I think). ...
3
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1answer
209 views

RAID mdadm virtual disk too small

sudo mdadm --build /dev/md0 --level=linear --raid-devices=3 /dev/loop0 /dev/sda1 /dev/sda2 After running the above command, /dev/md0 is smaller than /dev/loop0 + /dev/sda1 + /dev/sda2. Why is that ...
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1answer
73 views

using dd command for folder, but deleted items don't seem deleted [closed]

here is the image I used dd command to create a new floppy. First I tried it with a folder filled with naber.bin, test.bin, blabla.bin and boot.bin. And then i deleted all except boot.bin. ls -a ...
2
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3answers
373 views

How can I copy three partitions of my disk with a specific beginning and ending using dd?

Using the fdisk -l command I got the following answer: Device Boot Start End Blocks Id System /dev/sda1 * 2048 28266495 14132224 27 Hidden NTFS WinRE ...
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2answers
2k views

Patching a binary with dd

I have read this quote (below) several times, most recently here, and am continually puzzled at how dd can be used to patch anything let alone a compiler: The Unix system I used at school, 30 ...
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5answers
130 views

How one can re-read image with dd so it will match one you just wrote?

I have a ~1GB image that I'm writing to a 8GB SD card via the dd tool. I'd like to verify that it was written without corruption by reading it back and comparing its hash with original one. ...
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1answer
51 views

how to use dd to backup second linux hard drive from os x?

I have a MacBook with Linux installed on the primary hard drive. On an external USB 3.0 drive, I have OS X installed. The external drive has plenty of space so I would like to boot up OS X and make ...
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4answers
330 views

How can I convert two-valued text data to binary (bit-representation)

I have a text file with two (2) only possible characters (and maybe new lines \n). Example: ABBBAAAABBBBBABBABBBABBB (Size 24 bytes) How can I convert this to a binary file, meaning a bit ...