dd is a traditional utility for binary data copies

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3answers
731 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 ...
1
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1answer
21 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 ...
4
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4answers
169 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 ...
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0answers
40 views

osx - dd command behaving weirdly [duplicate]

I've been using dd for a couple of years now, most of the time successfully. I usually use it to dd Linux images to USB drives. My workflow doing so is as such: convert .iso image to a .img format ...
4
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1answer
38 views

How to write to an .img file with two different partitions?

I have been working on building a Linux based OS for Raspberry-pi using buildroot. I am generating the required empty .img file using "dd" and "fdisk" utilities. I am creating two empty partitions ...
4
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2answers
53 views

What is actually the speed reported by dd?

I always thought that when doing: dd if=/dev/sdx of=/dev/sdy the report which is displayed once the command finishes, such as: 79304319+0 records in 79304319+0 records out 40603811328 bytes (41 ...
1
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1answer
36 views

How to clone an MTPFS partition of a mounted Android phone?

Using mtpfs I've mounted a Samsung Galaxy S5 and I need to make an image of its root partition. I want to use dd or the like, but nothing seems to be able to detect/reference an MTP and/or FUSE ...
38
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4answers
17k views

Is there a way to determine the optimal value for the bs parameter to dd?

On occasion I've seen comments online along the lines of "make sure you set 'bs=' because the default value will take too long," and my own extremely-unscientific experiences of, "well that seemed to ...
3
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1answer
40 views

Size difference between an iso file burnt to a cd and the file retrieved with dd

I have an iso file (foo.iso) that I burnt to a dvd with the command : growisofs -dvd-compat -Z /dev/cdrom=foo.iso I then tried the command dd if=/dev/cdrom of=foo2.iso However, foo2.iso is ...
14
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3answers
13k views

How to dd a remote disk using SSH on local machine and save to a local disk

How can I create a backup of a remote disk using SSH on my local machine and save it to a local disk? I've tried the following: ssh hostname@my.ip.address "sudo dd if=/dev/sdX " | \ dd ...
1
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1answer
54 views

cant run dd command on android device

The main objective is to send a splited file to an android and join it back up with a .sh script, the file is splited to 5MB parts but its total size is unknown (trying to make an universal script), ...
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0answers
27 views

Making an ISO of MBR + X amounts of partitions

I am trying to make an ISO of a Windows Backup disc that I "burned" to my microSD card, which I did in desperation due to lack of HDD storage at the time. Now I want to get it out of there and onto ...
30
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5answers
24k views

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 ...
0
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1answer
36 views

Hard Disk Clone Image Size

I've created an image backup for HDDA (partition) from HostA and saved on HostB ssh -c blowfish user@ip-or-hostname "dd if=/dev/sda1 | gzip -1 -" | dd of=sda1.gz conv=sync,noerror The HDD size is ...
1
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3answers
468 views

DD and Free Space

I have a partition (/dev/sda1) of 10 GB. Also have "dd" file of another 7 GB partition ( /dev/sdb1). When I execute the command as: dd if=sdb1.dd of=/dev/sda1 then everything goes fine but I ...
61
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7answers
11k views

dd vs cat — is dd still relevant these days?

I recently realized we can use cat as much as dd, and it's actually faster than dd I know that dd was useful in dealing with tapes where block size actually mattered in correctness, not just ...
2
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0answers
27 views

Can't figure out what all these sd drives are

So I created a WindowsXP install using an NTFS drive in VMPlayer and now I want to make an image of it using dd. Here is the diskpart info from Windows: Then I use Kali as a live-cd and I find like ...
3
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1answer
80 views

dd shows a random number of records in/out [duplicate]

I'm writing some images back to block devices, with dd, and getting very strange output I've never seen before. # xz -dc goren.img.xz | dd bs=1M of=/dev/storage2/goren 35+2475166 records in ...
3
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4answers
2k 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 ...
0
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2answers
61 views

Writing ISO file to USB

I need to write a windows7 iso file on my usb stick. I had been used to this task. I usually either use the dd tool, or unetbootin. Surprisingly both don't work today. With dd I did the following : ...
0
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1answer
26 views

How to image certain portions of hard drive only

I have a failed hard drive which I need to extract data from. My dd kung fu is failing me right now. I know that the drive is failing at sector 60515007 to 60517093 (512b per sector), and multiple ...
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6answers
7k views

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 ...
4
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1answer
276 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 - ...
3
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1answer
39 views

How to inspect the raw contents of a partition?

I'm trying to see the contents in raw bytes of a dummy partition /dev/sda3, which I've made to be 100MiB through gparted. I want to test writing and reading on that partition. Is there a tool that ...
9
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5answers
327 views

How to pad a file to a desired size?

I have a file that I want to pad until it reaches 16 MiB (16777216 bytes). Currently it is 16515072 bytes. The difference is 262144 bytes. How do I pad it? This doesn't seem to be working: cp ...
1
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4answers
98 views

Change only one bit in a file

I have to test a hash function and I want to change only a single bit of a specific file. I tried with the dd command. That works, but I can only change a whole byte and not just a bit. sudo dd ...
0
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0answers
35 views

What are the [internal] steps involved in making USB drive 'bootable'?

Whenever I have to install a new Linux distro, I create a bootable USB from the distro image using some specialized program like UNetBootin. Recently, I tried to do for Fedora using 'dd' command, but ...
2
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2answers
190 views

Multiple passes of wiping disk with `dd`

I want to use dd to overwrite a disk multiple times to destroy data beyond recovery. I know I could use dd if=/dev/zero/ of=/dev/sdx/ to do a pass with zeros, or dd if=/dev/null/ of=/dev/sdx/ to ...
4
votes
5answers
4k views

Fast Way to Randomize HD?

I've read about how to make hard drives secure for encryption, and one of the steps is to write random bits to the drive, in order to make the encrypted data indistinguishable from the rest of the ...
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0answers
237 views

USB Stick recognized but not mountable

I have a USB Stick which is recognized by my laptop but there is no partition to mount. The device is listed in /dev/ as sdb but no partition /dev/sdb1. fdisk -l also displays nothing about /dev/sdb. ...
2
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1answer
58 views

Syntax When Combining dd and pv

I am a linux newbie; so, sorry if this is obvious to you... sudo dd if=/dev/sda bs=64k | pv --size 1.5t | dd of=/dev/sdb Does the block size for dd go on the left side of this after the input as ...
1
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1answer
71 views

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 ...
21
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4answers
8k views

What does dd stand for?

I know very well what the command does, but man dd, info dd tell me: 'Convert and copy a file', as does GNU Coreutils. Google says its an abbreviation of everything between medicine and bad webchat ...
36
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3answers
5k views

When is dd suitable for copying data? (or, when are read() and write() partial)

Short version: In what circumstances is dd safe to use for copying data, safe meaning that there is no risk of corruption due to a partial read or write? Long version — preamble: dd is often used to ...
3
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2answers
3k 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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0answers
76 views

Overwritten superblock and dd backup files recovery

Good day, yesterday I tried to extend my swap partition ('cause suspend/hibernation didn't work) and I needed to decrease size of my debian linux disk (I don't ever remember if it was ext2/et3 or ...
4
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4answers
409 views

How to fill a file with a stream from /dev/urandom with a specified number of lines ?

I am trying to fill a file with a sequence of random 0 and 1s with a user-defined number of lines and number of characters per line. the first step is to get a random stream of 0 and 1s: cat ...
19
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4answers
5k views

Why does dd from /dev/random give different file sizes?

I am running the following command on an ubuntu system: dd if=/dev/random of=rand bs=1K count=2 However, every time I run it, I end up with a file of a different size. Why is this? How can I ...
6
votes
3answers
1k views

Linux/GParted can see partition table but dd bs=512 count=1 can't

I have an MBR formatted sd card and when connect to a Linux machine (xubuntu 12.04) it can mount a partition and parse the file system (as can GParted). However, when I try to read the MBR from the ...
1
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1answer
66 views

How can I cross compile the dd linux tool for arm?

I need to cross-compile a full version of dd because my device only has a busybox one that doesn't support many options. Where do I get the source for it? I've been looking on the kernel repo online ...
8
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5answers
715 views

Why specify block size when copying devices of a finite size?

In online tutorials it is often suggested to use the following command to copy a CDROM to an iso image: $ dd if=/dev/dvd of=foobar.iso bs=2048 Why must the byte size be specified? I notice that in ...
0
votes
1answer
175 views

extract number of bytes out of a file

Is it possible to extract a few number of bytes out of a file using dd ? The file is located on a secondary drive. I apologize if this is a simple question however I'm no pro at command line.
1
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1answer
76 views

dd'ing SDD, decreasing write speed

My hard drive is a SanDisk SSD. The drive is new. I've booted into ArchLinux Live System, with the intention of preparing the hard drive for full disk encryption. I've noticed a significant drop of ...
4
votes
2answers
168 views

How to delete part of a binary file without copying

I need to delete the first 2 bytes of a 6MB file. However, this is an embedded Linux with only 32 Mbytes RAM and less than 1 MB free flash memory. I tried using dd, as: 1 - # dd bs=1 skip=2 ...
32
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7answers
22k views

Best way to remove bytes from the start of a file?

Today I had to remove the first 1131 bytes from an 800MB mixed text / binary file, a filtered subversion dump I'm hacking for a new repository. What's the best way to do this? To start with I tried ...
3
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0answers
50 views

Have I destroyed data on drive?

I stupidly ran the following command on an external ext4 USB disk, typing /dev/sdb instead of /dev/sda which was the new disk I was setting up: dd if=/dev/zero of=/dev/sda bs=512 count=100 These ...
4
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2answers
453 views

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
169 views

How to create a new partitioning table on SD card from the command line ? [closed]

I have tried to mount a SD card on Linux Mint, I have found the right device file and tried: mount -t vfat /dev/sdb /mnt/zauberportal ,but it failed and I tried some variations like different types of ...
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2answers
30 views

MBR and data on pendrive

I have a pendrive (/dev/sdd). I ran fdisk -l and that shows me the drive and its partitions. After that I did: dd if=/dev/zero of=/dev/sdd bs=512 count=1 I deleted the MBR (so the partitions ...
0
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2answers
33 views

Cloning a drive larger than your own

I made this nice backup system to turn drives into vdi's and put them on our network share. Then the next day my boss walks in with 20 new machines to replace our old ones, they have 2TB drives. How ...