Commands using dd (167)

  • I wanted to create a copy of my whole laptop disk on an lvm disk of the same size. First I created the logical volume: lvcreate -L120G -nlaptop mylvms SOURCE: dd if=/dev/sda bs=16065b | netcat ip-target 1234 TARGET: nc -l -p 1234 | dd of=/dev/mapper/mylvms-laptop bs=16065b to follow its process you issue the following command in a different terminal STATS: on target in a different terminal: watch -n60 -- kill -USR1 $(pgrep dd) (see http://www.commandlinefu.com/commands/view/4356/output-stats-from-a-running-dd-command-to-see-its-progress)


    6
    SOURCE: dd if=/dev/sda bs=16065b | netcat ip-target 1234 TARGET: netcat -l -p 1234 | dd of=/dev/mapper/laptop bs=16065b STATS on target: watch -n60 -- kill -USR1 $(pgrep dd)
    bw · 2009-12-16 10:51:06 1
  • The above command will send 4GB of data from one host to the next over the network, without consuming any unnecessary disk on either the client nor the host. This is a quick and dirty way to benchmark network speed without wasting any time or disk space. Of course, change the byte size and count as necessary. This command also doesn't rely on any extra 3rd party utilities, as dd, ssh, cat, /dev/zero and /dev/null are installed on all major Unix-like operating systems. Show Sample Output


    6
    dd if=/dev/zero bs=4096 count=1048576 | ssh [email protected] 'cat > /dev/null'
    atoponce · 2010-06-08 18:49:51 5
  • An easy method to generate ISOs from CD/DVD media.


    6
    dd if=/dev/cdrom of=~/cdrom_image.iso
    o0110o · 2012-07-10 06:03:25 6
  • This example will close the pipe after transferring 100MB at a speed of 3MB per second.


    6
    cat /dev/urandom | pv -L 3m | dd bs=1M count=100 iflag=fullblock > /dev/null
    bugmenot · 2012-07-29 00:42:16 2
  • This is just a proof of concept: A FILE WHICH CAN AUTOMOUNT ITSELF through a SIMPLY ENCODED script. It takes advantage of the OFFSET option of mount, and uses it as a password (see that 9191? just change it to something similar, around 9k). It works fine, mounts, gets modified, updated, and can be moved by just copying it. USAGE: SEE SAMPLE OUTPUT The file is composed of three parts: a) The legible script (about 242 bytes) b) A random text fill to reach the OFFSET size (equals PASSWORD minus 242) c) The actual filesystem Logically, (a)+(b) = PASSWORD, that means OFFSET, and mount uses that option. PLEASE NOTE: THIS IS NOT AN ENCRYPTED FILESYSTEM. To improve it, it can be mounted with a better encryption script and used with encfs or cryptfs. The idea was just to test the concept... with one line :) It applies the original idea of http://www.commandlinefu.com/commands/view/7382/command-for-john-cons for encrypting the file. The embedded bash script can be grown, of course, and the offset recalculation goes fine. I have my own version with bash --init-file to startup a bashrc with a well-defined environment, aliases, variables. Show Sample Output


    6
    dd if=/dev/zero of=T bs=1024 count=10240;mkfs.ext3 -q T;E=$(echo 'read O;mount -o loop,offset=$O F /mnt;'|base64|tr -d '\n');echo "E=\$(echo $E|base64 -d);eval \$E;exit;">F;cat <(dd if=/dev/zero bs=$(echo 9191-$(stat -c%s F)|bc) count=1) <(cat T;rm T)>>F
    rodolfoap · 2013-01-31 01:38:30 5
  • This shell snippet reads a single keypress from stdin and stores it in the $KEY variable. You do NOT have to press the enter key! The key is NOT echoed to stdout! This is useful for implementing simple text menus in scripts and similar things.


    5
    stty cbreak -echo; KEY=$(dd bs=1 count=1 2>/dev/null); stty -cbreak echo
    inof · 2009-06-09 13:15:49 4

  • 5
    dd bs=1 seek=2TB if=/dev/null of=ext3.test
    Superhuman · 2009-09-03 08:35:20 0
  • This command clone the first partition of the primary master IDE drive to the second partition of the primary slave IDE drive (!!! back up all data before trying anything like this !!!)


    5
    sudo dd if=/dev/hda1 of=/dev/hdb2
    0disse0 · 2009-09-05 09:16:52 0
  • You can use this to directly dump from machine A (with dvd drive) to machine B (without dvd drive) . I used this to copy dvd using my friend's machine to my netbook. Above command is to be issued on machine B. Advantages : 1) No wasting time dumping first to machine A and then copying to Machine B. 2) You dont need to use space on Machine A. In fact, this will work even when Machine A doesnt have enough hdd space to dump the DVD. Use -C ssh option on slow networks (enables compression). you can replace "dd if=/dev/dvd" with any ripping command as long as it spews the iso to stdout.


    5
    ssh [email protected]_A dd if=/dev/dvd0 > dvddump.iso
    kamathln · 2009-09-11 18:08:36 5
  • A bit different from some of the other submissions. Has bold and uses all c printable characters. Change the bs=value to speed up and increase the sizes of the bold and non-bold strings.


    5
    echo -ne "\e[32m" ; while true ; do echo -ne "\e[$(($RANDOM % 2 + 1))m" ; tr -c "[:print:]" " " < /dev/urandom | dd count=1 bs=50 2> /dev/null ; done
    psykotron · 2009-12-19 19:05:04 1

  • 5
    dd if=/dev/zero of=foo.txt bs=1M count=1
    EBAH · 2010-10-20 09:36:34 0
  • Install a basic FreeBSD system on a distant server. I use this to install FreeBSD on servers that can only boot a Linux rescue system. This sytem loads on ram when booted, so it is possible to install freely. You can even install on ZFS root !


    5
    dd if=mfsbsd.iso | ssh distant.server dd of=/dev/sda
    gormux · 2010-12-23 09:34:33 3
  • usage: mem memcache-command [arguments] where memcache-command might be: set add get[s] append prepend replace delete incr decr cas stats verbosity version notes: exptime argument is set to 0 (no expire) flags argument is set to 1 (arbitrary)


    5
    mem(){ { case $1 in st*|[vgid]*) printf "%s " "[email protected]";; *) dd if=$3 2>&1|sed '$!d;/^0/d;s/ .*//;s/^/'"$1"' '"$2"' 1 0 /; r '"$3"'' 2>/dev/null;;esac;printf "\r\nquit\r\n";}|nc -n 127.0.0.1 11211; }
    argv · 2011-06-17 06:39:07 2

  • 5
    sudo dd if=/dev/sdc bs=4096 | pv -s `sudo mount /dev/sdc /media/sdc && du -sb /media/sdc/ |awk '{print $1}' && sudo umount /media/sdc`| sudo dd bs=4096 of=~/USB_BLACK_BACKUP.IMG
    juanmi · 2013-02-06 09:29:10 2
  • This is similar to how you would generate a file with all zeros dd if=/dev/zero of=allzeros bs=1024 count=2k


    4
    tr '\000' '\377' < /dev/zero | dd of=allones bs=1024 count=2k
    azeey · 2009-12-08 16:05:28 1
  • This is a more accurate way to watch the progress of a dd process. The $DDPID=$! is needed so that you don't get the PID of the sleep. The sleep 1 is needed because in my testing at least, if you run kill -USR1 against dd too quickly, it will kill it off instead of display the status. So you need to wait a second, probably so that it can configure itself to trap the USR1 signal. Show Sample Output


    4
    dd if=fromfile of=tofile & DDPID=$! ; sleep 1 ; while kill -USR1 $DDPID ; do sleep 5; done
    deltaray · 2010-01-12 15:01:44 1
  • Useful for testing purposes


    4
    dd if=/dev/zero of=testfile bs=1024 count=5000
    mpathi · 2011-03-25 09:08:50 0
  • the speed is about 500MB/s on my machine. i think it's fast enough to output not too many bytes. while a C program may output 1GB per sencond on my machine. if the size is not the power of 512,you may change the bs and count in dd. Show Sample Output


    4
    tr '\0' '\377' < /dev/zero|dd count=$((<bytes>/512))
    cfy · 2011-04-05 14:26:02 0
  • create an iso from your cd/dvd-rom device . You need to umount /dev/cdrom before using the cli Show Sample Output


    4
    dd if=/dev/cdrom of=~/cd_image.iso
    eastwind · 2011-09-24 15:27:04 3
  • Your platform may not have pv by default. If you are using Homebew on OSX, simply 'brew install pv'. Show Sample Output


    4
    pv -tpreb /dev/sda | dd of=/dev/sdb bs=1M
    sc0ttyd · 2013-08-19 23:04:15 1

  • 3
    dd if=/dev/random of=bigfile bs=1024 count=102400
    amiga500 · 2009-02-17 05:41:20 2
  • See: http://imgur.com/JgjK2.png for example. Do some serious benchmarking from the commandline. This will write to a file with the time it took to compress n bytes to the file (increasing by 1). Run: gnuplot -persist <(echo "plot 'lzma' with lines, 'gzip' with lines, 'bzip2' with lines") To see it in graph form.


    3
    for a in bzip2 lzma gzip;do echo -n>$a;for b in $(seq 0 256);do dd if=/dev/zero of=$b.zero bs=$b count=1;c=$(date +%s%N);$a $b.zero;d=$(date +%s%N);total=$(echo $d-$c|bc);echo $total>>$a;rm $b.zero *.bz2 *.lzma *.gz;done;done
    matthewbauer · 2009-10-20 01:00:51 2
  • The following command will clone usb stick inside /dev/sdc to /dev/sdd Double check you got the correct usb sticks (origional-clone)with fdisk -l.


    3
    dd if=/dev/sdc of=/dev/sdd conv=notrunc & while killall -USR1 dd; do sleep 5; done
    bw · 2010-01-12 14:09:40 3
  • Note: Replace 200000 with drive bytes/512, and /dev/sdx with the destination drive/partition. ;) Note: You may need to install pipebench, this is easy with "sudo apt-get install pipebench" on Ubuntu. The reason I hunted around for the pieces to make up this command is that I wanted to specifically flip all of the bits on a new HDD, before running an Extended SMART Self-Test (actually, the second pass, as I've already done one while factory-zeroed) to ensure there are no physical faults waiting to compromise my valuable data. There were several sites that came up in a Google search which had a zero-fill command with progress indicator, and one or two with a fill-with-ones command, but none that I could find with these two things combined (I had to shuffle around the dd command(s) to get this to happen without wasting speed on an md5sum as well). For reference, these are the other useful-looking commands I found in my search: Zero-fill drive "/dev/sdx", with progress indicator and md5 verification (run sudo fdisk -l to get total disk bytes, then divide by 512 and enter the resulting value into this command for a full wipe) dd if=/dev/zero bs=512 count=<size/512> | pipebench | sudo tee /dev/sdx | md5sum And this command for creating a file filled with ones is my other main source (besides the above command and man pages, that is - I may be a Linux newbie but I do read!): tr '\000' '\377' < /dev/zero | dd of=allones bs=1024 count=2k Hope someone finds this useful! :) Cheers, - Gliktch Show Sample Output


    3
    tr '\000' '\377' < /dev/zero | dd bs=512 count=200000 status=noxfer | pipebench | sudo dd of=/dev/sdx
    Gliktch · 2010-08-31 15:38:27 1
  • Adjust "sleep X" to your needs. *NOTE: First sleep is required because bash doesn't have a "post-test" syntax (do XXX while). Show Sample Output


    3
    dd if=/path/to/inputfile of=/path/to/outputfile & pid=$! && sleep X && while kill -USR1 $pid; do sleep X; done
    cyrusza · 2010-12-02 15:07:18 3
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Copy a file using dd and watch its progress
This is a more accurate way to watch the progress of a dd process. The $DDPID=$! is needed so that you don't get the PID of the sleep. The sleep 1 is needed because in my testing at least, if you run kill -USR1 against dd too quickly, it will kill it off instead of display the status. So you need to wait a second, probably so that it can configure itself to trap the USR1 signal.

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