Pipe Viewer

If you have ever copied data from one disk to another using dd, you will have noticed that dd has no progress bar, no ETA, no information at all until the process has completed. This can be troublesome if you are copying large partitions that are likely to take a few hours.

I found a little program called pv that solves that problem. pv allows you to see into the pipe and see what is going on with your copy process.

To use pv simply break the dd process into two parts, one reading the input, one writing the output, and pass the data through pv.

:!: BE VERY CAREFUL WHEN USING DD :!:
You can easily destroy all the data on your disk if used incorrectly.

user@host ~
$ dd if=/dev/sda of=/dev/sdb
user@host ~
$ dd if=/dev/sda | pv | dd of=/dev/sdb
225MB 0:00:12 [31.7MB/s] [==============>                    ] 43% ETA 0:00:10

pv can be used with other programs such as gzip, bzcat, nc and many more. Try replacing cat with pv in your current commands to see if you can view your current progress.

One thought on “Pipe Viewer

  1. This works great! It's also good to use for viewing the progress of zeroing out free space:
    dd if=/dev/zero | pv | dd of=delete bs=1M

    Thanks!

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