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Tomáš Pečený
Asked: 2019-12-04 04:29:23 +0800 CST

Check after Copying

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Sometimes I copy a lot of data using the 

dd if=/dev/sda of=/dev/sdb
command. Recently, that copying made a bug that I have found only accidentally. Which command should I use to compare the original and the copy? The 

info diff

apparently does not show that such sort of parameters can be used with the diff command.

command-line partitioning

1 Answers

  1. assuming source and destination drives are identical size, compare md5sum of source and destination.

    md5sum /dev/source
md5sum /dev/dest

    this should also work if destination is an image file.

    If physical destination drive is larger than physical source drive (or file), you'll need to request MD5SUM of the destination, selecting the same number of blocks as copied.

    dd if=/dev/dest bs=n count=n | md5sum
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